Ω
People who eat baked or broiled fish on a weekly basis may be improving their brain health and reducing their risk of developing mild cognitive impairment (MCI) and Alzheimer's disease, according to a study presented today at the annual meeting of the Radiological Society of North America (RSNA).
"This is the first study to establish a direct relationship between fish consumption, brain structure and Alzheimer's risk," said Cyrus Raji, M.D., Ph.D., from the University of Pittsburgh Medical Center and the University of Pittsburgh School of Medicine. "The results showed that people who consumed baked or broiled fish at least one time per week had better preservation of gray matter volume on MRI in brain areas at risk for Alzheimer's disease."
Alzheimer's disease is an incurable, progressive brain disease that slowly destroys memory and cognitive skills. According to the National Institute on Aging, as many as 5.1 million Americans may have Alzheimer's disease. In MCI, memory loss is present but to a lesser extent than in Alzheimer's disease. People with MCI often go on to develop Alzheimer's disease.
For the study, 260 cognitively normal individuals were selected from the Cardiovascular Health Study. Information on fish consumption was gathered using the National Cancer Institute Food Frequency Questionnaire. There were 163 patients who consumed fish on a weekly basis, and the majority ate fish one to four times per week. Each patient underwent 3-D volumetric MRI of the brain. Voxel-based morphometry, a brain mapping technique that measures gray matter volume, was used to model the relationship between weekly fish consumption at baseline and brain structure 10 years later. The data were then analyzed to determine if gray matter volume preservation associated with fish consumption reduced risk for Alzheimer's disease. The study controlled for age, gender, education, race, obesity, physical activity, and the presence or absence of apolipoprotein E4 (ApoE4), a gene that increases the risk of developing Alzheimer's.
Gray matter volume is crucial to brain health. When it remains higher, brain health is being maintained. Decreases in gray matter volume indicate that brain cells are shrinking.
The findings showed that consumption of baked or broiled fish on a weekly basis was positively associated with gray matter volumes in several areas of the brain. Greater hippocampal, posterior cingulate and orbital frontal cortex volumes in relation to fish consumption reduced the risk for five-year decline to MCI or Alzheimer's by almost five-fold.
"Consuming baked or broiled fish promotes stronger neurons in the brain's gray matter by making them larger and healthier," Dr. Raji said. "This simple lifestyle choice increases the brain's resistance to Alzheimer's disease and lowers risk for the disorder."
The results also demonstrated increased levels of cognition in people who ate baked or broiled fish.
"Working memory, which allows people to focus on tasks and commit information to short-term memory, is one of the most important cognitive domains," Dr. Raji said. "Working memory is destroyed by Alzheimer's disease. We found higher levels of working memory in people who ate baked or broiled fish on a weekly basis, even when accounting for other factors, such as education, age, gender and physical activity."
Eating fried fish, on the other hand, was not shown to increase brain volume or protect against cognitive decline.
More on Alzheimer's:
According to statistics from the National Institute on Aging, Alzheimer’s disease is the most common form of dementia in older people. Alzheimer’s is a progressive brain disease; it is irreversible and causes a decline in memory and cognitive skills.
Alzheimer’s disease is the seventh leading cause of death in the United States. It is the only cause of death among the top 10 that cannot be prevented, cured or even significantly arrested. Two-thirds of people over the age of 65 who have the disease are women. This is a startling statistic, and one that requires increased attention and research.
“Clearly, this is an illness of women more than men,” said Victor Henderson, MD, MS, Professor of Epidemiology and Neurology and Neurological Sciences at Stanford University. “In part, it has to do with the fact that women live longer than men. There are real differences in longevity.”
Researchers have long studied the relationship between the hormone estrogen and Alzheimer's disease, but the results have been inconclusive thus far. “There are other risk factors that may come into play,” said Henderson, “which can further explain why women may be predisposed to Alzheimer’s disease.” Some of these factors include: family history, genetics, and some evidence suggests heart disease.
One of the first signs of Alzheimer’s disease may be forgetfulness and difficulty remembering newly learned information. But the disease gradually gets worse. According to the National Alzheimer’s Association in Chicago, other symptoms develop over time and may include:
• Challenges in planning or problem solving.
• Difficulty completing familiar tasks at home, at work, or at leisure.
• Confusion with time or place.
• Trouble understanding visual images and spatial relationships.
• New problems with words in speech or writing.
• Misplacing objects and losing the ability to retrace steps.
• Decreased or poor judgment.
• Withdrawal from work or social activities.
• Changes in mood and personality.
Wednesday, November 30, 2011
Anti-inflammatory polyphenols in apple peels
Ω
Here's another reason why "an apple a day keeps the doctor away"—according to new research findings published in the Journal of Leukocyte Biology, oral ingestion of apple polyphenols (antioxidants found in apple peels) can suppress T cell activation to prevent colitis in mice. This study is the first to show a role for T cells in polyphenol-mediated protection against an autoimmune disease and could lead to new therapies and treatments for people with disorders related to bowel inflammation, such as ulcerative colitis, Crohn's disease and colitis-associated colorectal cancer.
"Many people with colitis use some form of dietary supplement to complement conventional therapies, but most of the information on the health effects of complementary medicine remains anecdotal. Also, little is known about exactly how these therapies work, if they work at all," said David W. Pascual, Ph.D., a researcher involved in the work from the Department of Immunology and Infectious Diseases at Montana State University in Bozeman, Montana. "Our results show that a natural product found in apple peels can suppress colonic inflammation by antagonizing inflammatory T cells to enhance resistance against autoimmune disease."
To make this discovery, scientists used a chemically induced model of colitis with Dextran sulfate sodium (DSS), researchers administered an oral placebo to one group of mice, and the other group of mice was given an oral dose of apple polyphenols every day during the course of the disease. Results showed that mice treated orally with apple polyphenols were protected from colitis. Importantly, scientists also found that the treated mice had fewer activated T cells in their colons. In mice lacking T cells, apple polyphenols were unable to protect against colitis or suppress proinflammatory cytokine expression, indicating apple polyphenols protect against colitis via the suppression of T cell activation and/or recruitment.
"It appears that the old adage rings true in more ways than one," said John Wherry, Ph.D., Deputy Editor of the Journal of Leukocyte Biology, "In addition to the obvious health benefits of the nutrients and fiber in fruits and vegetables, this study indicates that even something as relatively common as the apple contains other healthy ingredients that can have serious therapeutic value."
Ω
Here's another reason why "an apple a day keeps the doctor away"—according to new research findings published in the Journal of Leukocyte Biology, oral ingestion of apple polyphenols (antioxidants found in apple peels) can suppress T cell activation to prevent colitis in mice. This study is the first to show a role for T cells in polyphenol-mediated protection against an autoimmune disease and could lead to new therapies and treatments for people with disorders related to bowel inflammation, such as ulcerative colitis, Crohn's disease and colitis-associated colorectal cancer.
"Many people with colitis use some form of dietary supplement to complement conventional therapies, but most of the information on the health effects of complementary medicine remains anecdotal. Also, little is known about exactly how these therapies work, if they work at all," said David W. Pascual, Ph.D., a researcher involved in the work from the Department of Immunology and Infectious Diseases at Montana State University in Bozeman, Montana. "Our results show that a natural product found in apple peels can suppress colonic inflammation by antagonizing inflammatory T cells to enhance resistance against autoimmune disease."
To make this discovery, scientists used a chemically induced model of colitis with Dextran sulfate sodium (DSS), researchers administered an oral placebo to one group of mice, and the other group of mice was given an oral dose of apple polyphenols every day during the course of the disease. Results showed that mice treated orally with apple polyphenols were protected from colitis. Importantly, scientists also found that the treated mice had fewer activated T cells in their colons. In mice lacking T cells, apple polyphenols were unable to protect against colitis or suppress proinflammatory cytokine expression, indicating apple polyphenols protect against colitis via the suppression of T cell activation and/or recruitment.
"It appears that the old adage rings true in more ways than one," said John Wherry, Ph.D., Deputy Editor of the Journal of Leukocyte Biology, "In addition to the obvious health benefits of the nutrients and fiber in fruits and vegetables, this study indicates that even something as relatively common as the apple contains other healthy ingredients that can have serious therapeutic value."
Ω
Tuesday, November 29, 2011
Frequent 'heading' in soccer can lead to brain injury and cognitive impairment
Ω
Using advanced imaging techniques and cognitive tests, researchers at Albert Einstein College of Medicine of Yeshiva University and Montefiore Medical Center , the University Hospital and academic medical center for Einstein, have shown that repeatedly heading a soccer ball increases the risk for brain injury and cognitive impairment. The imaging portion of the findings was presented today at the annual meeting of the Radiological Society of North America (RSNA) in Chicago.
The researchers used diffusion tensor imaging (DTI), an advanced MRI-based imaging technique, on 38 amateur soccer players (average age: 30.8 years) who had all played the sport since childhood. They were asked to recall the number of times they headed the ball during the past year. (Heading is when players deliberately hit or field the soccer ball with their head.) Researchers ranked the players based on heading frequency and then compared the brain images of the most frequent headers with those of the remaining players. They found that frequent headers showed brain injury similar to that seen in patients with concussion, also known as mild traumatic brain injury (TBI).
The findings are especially concerning given that soccer is the world's most popular sport with popularity growing in the U.S., especially among children. Of the 18 million Americans who play soccer, 78 percent are under the age of eighteen. Soccer balls are known to travel at speeds as high as 34 miles per hour during recreational play, and more than twice that during professional play.
After confirming the potentially damaging impact of frequent heading, "Our goal was to determine if there is a threshold level for heading frequency that, when surpassed, resulted in detectable brain injury," said lead author Michael Lipton, M.D., Ph.D. , associate director of Einstein's Gruss Magnetic Resonance Research Center and medical director of MRI services at Montefiore. Further analysis revealed a threshold level of approximately 1,000 to 1,500 heads per year. Once players in the study exceeded that number, researchers observed significant injury.
"While heading a ball 1,000 or 1,500 times a year may seem high to those who don't participate in the sport, it only amounts to a few times a day for a regular player," observed Dr. Lipton, who is also associate professor of radiology, of psychiatry and behavioral sciences ), and of the Dominick P. Purpura Department of Neuroscience at Einstein.
"Heading a soccer ball is not an impact of a magnitude that will lacerate nerve fibers in the brain," said Dr. Lipton. "But repetitive heading may set off a cascade of responses that can lead to degeneration of brain cells."
Researchers identified five areas, in the frontal lobe (behind the forehead) and in the temporo-occipital region (the bottom-rear areas) of the brain that were affected by frequent heading – areas that are responsible for attention, memory, executive functioning and higher-order visual functions. In a related study, Dr. Lipton and colleague Molly Zimmerman, Ph.D. , assistant professor in the Saul R. Korey Department of Neurology at Einstein, gave the same 38 amateur soccer players tests designed to assess their neuropsychological function. Players with the highest annual heading frequency performed worse on tests of verbal memory and psychomotor speed (activities that require mind-body coordination, like throwing a ball) relative to their peers.
"These two studies present compelling evidence that brain injury and cognitive impairment can result from heading a soccer ball with high frequency," Dr. Lipton said. "These are findings that should be taken into consideration in planning future research to develop approaches to protect soccer players."
Heading is an essential part of soccer and is unlikely to be eliminated from practice or play.
As there appears to be a safe range for heading frequency, additional research can help refine this number, which can then be used to establish heading guidelines. As in other sports, the frequency of potentially harmful actions in practice and games could be monitored and restricted based on confirmed unsafe exposure thresholds.
"In the past, pitchers in Little League Baseball sustained shoulder injuries at a rate that was alarming," Dr. Lipton noted. "But ongoing research has helped shape various approaches, including limits on the amount of pitching a child performs, which have substantially reduced the incidence of these injuries."
"Brain injury due to heading in children, if we confirm that it occurs, may not show up on our radar because the impairment will not be immediate and can easily be attributed to other causes like ADHD or learning disabilities," continued Dr. Lipton. "We, including the agencies that supervise and encourage soccer play, need to do the further research to precisely define the impact of excessive heading on children and adults in order to develop parameters within which soccer play will be safe over the long term."
Using advanced imaging techniques and cognitive tests, researchers at Albert Einstein College of Medicine of Yeshiva University and Montefiore Medical Center , the University Hospital and academic medical center for Einstein, have shown that repeatedly heading a soccer ball increases the risk for brain injury and cognitive impairment. The imaging portion of the findings was presented today at the annual meeting of the Radiological Society of North America (RSNA) in Chicago.
The researchers used diffusion tensor imaging (DTI), an advanced MRI-based imaging technique, on 38 amateur soccer players (average age: 30.8 years) who had all played the sport since childhood. They were asked to recall the number of times they headed the ball during the past year. (Heading is when players deliberately hit or field the soccer ball with their head.) Researchers ranked the players based on heading frequency and then compared the brain images of the most frequent headers with those of the remaining players. They found that frequent headers showed brain injury similar to that seen in patients with concussion, also known as mild traumatic brain injury (TBI).
The findings are especially concerning given that soccer is the world's most popular sport with popularity growing in the U.S., especially among children. Of the 18 million Americans who play soccer, 78 percent are under the age of eighteen. Soccer balls are known to travel at speeds as high as 34 miles per hour during recreational play, and more than twice that during professional play.
After confirming the potentially damaging impact of frequent heading, "Our goal was to determine if there is a threshold level for heading frequency that, when surpassed, resulted in detectable brain injury," said lead author Michael Lipton, M.D., Ph.D. , associate director of Einstein's Gruss Magnetic Resonance Research Center and medical director of MRI services at Montefiore. Further analysis revealed a threshold level of approximately 1,000 to 1,500 heads per year. Once players in the study exceeded that number, researchers observed significant injury.
"While heading a ball 1,000 or 1,500 times a year may seem high to those who don't participate in the sport, it only amounts to a few times a day for a regular player," observed Dr. Lipton, who is also associate professor of radiology, of psychiatry and behavioral sciences ), and of the Dominick P. Purpura Department of Neuroscience at Einstein.
"Heading a soccer ball is not an impact of a magnitude that will lacerate nerve fibers in the brain," said Dr. Lipton. "But repetitive heading may set off a cascade of responses that can lead to degeneration of brain cells."
Researchers identified five areas, in the frontal lobe (behind the forehead) and in the temporo-occipital region (the bottom-rear areas) of the brain that were affected by frequent heading – areas that are responsible for attention, memory, executive functioning and higher-order visual functions. In a related study, Dr. Lipton and colleague Molly Zimmerman, Ph.D. , assistant professor in the Saul R. Korey Department of Neurology at Einstein, gave the same 38 amateur soccer players tests designed to assess their neuropsychological function. Players with the highest annual heading frequency performed worse on tests of verbal memory and psychomotor speed (activities that require mind-body coordination, like throwing a ball) relative to their peers.
"These two studies present compelling evidence that brain injury and cognitive impairment can result from heading a soccer ball with high frequency," Dr. Lipton said. "These are findings that should be taken into consideration in planning future research to develop approaches to protect soccer players."
Heading is an essential part of soccer and is unlikely to be eliminated from practice or play.
As there appears to be a safe range for heading frequency, additional research can help refine this number, which can then be used to establish heading guidelines. As in other sports, the frequency of potentially harmful actions in practice and games could be monitored and restricted based on confirmed unsafe exposure thresholds.
"In the past, pitchers in Little League Baseball sustained shoulder injuries at a rate that was alarming," Dr. Lipton noted. "But ongoing research has helped shape various approaches, including limits on the amount of pitching a child performs, which have substantially reduced the incidence of these injuries."
"Brain injury due to heading in children, if we confirm that it occurs, may not show up on our radar because the impairment will not be immediate and can easily be attributed to other causes like ADHD or learning disabilities," continued Dr. Lipton. "We, including the agencies that supervise and encourage soccer play, need to do the further research to precisely define the impact of excessive heading on children and adults in order to develop parameters within which soccer play will be safe over the long term."
Mediterranean Diet and Exercise Can Reduce Sleep Apnea Symptoms
Ω
Eating a Mediterranean diet combined with physical activity can help to improve some of the symptoms of sleep apnea, according to new research. The study, which is published online in the European Respiratory Journal, looked at the impact a Mediterranean diet can have on obese people with sleep apnea, compared to those on a prudent diet.
Obstructive sleep apnea syndrome (OSAS) causes frequent pauses of breathing to occur during sleep, which disrupts a person's normal sleeping pattern. It is one of the most prevalent sleep-related breathing disorders with approximately 2-4% of the adult population experiencing the condition. This percentage increases up to 20-40% with obesity, and weight loss is often an essential part of the recommended treatment plan.
The researchers, from the University of Crete in Greece, examined 40 obese patients suffering from OSAS. Twenty patients were given a prudent diet to follow, while the other 20 followed a Mediterranean diet. Both groups were also encouraged to increase their physical activity, mainly involving walking for at least 30 minutes each day.
In both groups, the patients also received continuous positive airway pressure (CPAP) therapy which involves wearing a mask that generates an air stream, keeping the upper airway open during sleep.
The researchers monitored the patients during a sleep study, known as polysomnography. This involved monitoring several markers for OSAS, including electrical activity in the brain, eye movements and snoring. The patients were examined at the start of the study and again 6 months later.
The results showed that people following the Mediterranean diet had a reduced number of disturbances, known as apneas, during the rapid eye movement (REM) stage of sleep, which usually accounts for approximately 25% of total sleep during the night.
The findings also revealed that people following the Mediterranean diet also showed a greater adherence to the calorie restricted diet, an increase in physical activity and a greater decrease in abdominal fat.
The results of this small sample did show an improvement during one stage of sleep for people with sleep apnea, however it did not show an overall improvement in severity of the condition. The authors suggest that further studies in a larger sample are required to fully understand the benefits of this diet.
Christopher Papandreou, lead author for the research, said: "This is the first study examining the impact of the Mediterranean diet in combination with physical activity on OSAS via changes in the human body. Our results showed that the number of disturbances during REM sleep was reduced more in the Mediterranean diet group than the other group. Recent reports have related an increase in disturbances during REM sleep with the risk of developing significant systemic consequences like diabetes type II. However, its clinical significance remains unclear. Finally, more studies are needed to examine the effect of the above diet on this sleep-related breathing disorder taking into account its anti-inflammatory and antioxidant properties."
Eating a Mediterranean diet combined with physical activity can help to improve some of the symptoms of sleep apnea, according to new research. The study, which is published online in the European Respiratory Journal, looked at the impact a Mediterranean diet can have on obese people with sleep apnea, compared to those on a prudent diet.
Obstructive sleep apnea syndrome (OSAS) causes frequent pauses of breathing to occur during sleep, which disrupts a person's normal sleeping pattern. It is one of the most prevalent sleep-related breathing disorders with approximately 2-4% of the adult population experiencing the condition. This percentage increases up to 20-40% with obesity, and weight loss is often an essential part of the recommended treatment plan.
The researchers, from the University of Crete in Greece, examined 40 obese patients suffering from OSAS. Twenty patients were given a prudent diet to follow, while the other 20 followed a Mediterranean diet. Both groups were also encouraged to increase their physical activity, mainly involving walking for at least 30 minutes each day.
In both groups, the patients also received continuous positive airway pressure (CPAP) therapy which involves wearing a mask that generates an air stream, keeping the upper airway open during sleep.
The researchers monitored the patients during a sleep study, known as polysomnography. This involved monitoring several markers for OSAS, including electrical activity in the brain, eye movements and snoring. The patients were examined at the start of the study and again 6 months later.
The results showed that people following the Mediterranean diet had a reduced number of disturbances, known as apneas, during the rapid eye movement (REM) stage of sleep, which usually accounts for approximately 25% of total sleep during the night.
The findings also revealed that people following the Mediterranean diet also showed a greater adherence to the calorie restricted diet, an increase in physical activity and a greater decrease in abdominal fat.
The results of this small sample did show an improvement during one stage of sleep for people with sleep apnea, however it did not show an overall improvement in severity of the condition. The authors suggest that further studies in a larger sample are required to fully understand the benefits of this diet.
Christopher Papandreou, lead author for the research, said: "This is the first study examining the impact of the Mediterranean diet in combination with physical activity on OSAS via changes in the human body. Our results showed that the number of disturbances during REM sleep was reduced more in the Mediterranean diet group than the other group. Recent reports have related an increase in disturbances during REM sleep with the risk of developing significant systemic consequences like diabetes type II. However, its clinical significance remains unclear. Finally, more studies are needed to examine the effect of the above diet on this sleep-related breathing disorder taking into account its anti-inflammatory and antioxidant properties."
Wednesday, November 23, 2011
Exercise helps us to eat a healthy diet
Ω
A healthy diet and the right amount of exercise are key players in treating and preventing obesity but we still know little about the relationship both factors have with each other. A new study now reveals that an increase in physical activity is linked to an improvement in diet quality.
Many questions arise when trying to lose weight. Would it be better to start on a diet and then do exercise, or the other way around? And how much does one compensate the other?
The data from epidemiological studies suggest that tendencies towards a healthy diet and the right amount of physical exercise often come hand in hand. Furthermore, an increase in physical activity is usually linked to a parallel improvement in diet quality.
Exercise also brings benefits such as an increase in sensitivity to physiological signs of fullness. This not only means that appetite can be controlled better but it also modifies hedonic responses to food stimuli. Therefore, benefits can be classified as those that occur in the short term (of metabolic predominance) and those that are seen in the long term (of behavioural predominance).
According to Alonso Alonso, "physical exercise seems to encourage a healthy diet. In fact, when exercise is added to a weight-loss diet, treatment of obesity is more successful and the diet is adhered to in the long run."
The authors of the study state how important it is for social policy to encourage and facilitate sport and physical exercise amongst the population. This should be present in both schools and our urban environment or daily lives through the use of public transport or availability of pedestrianised areas and sports facilities.
Exercise modifies the brain
Eating and physical activity are behaviours and are therefore influenced by cognitive processes that are a result of activity in different areas of the brain. Previous studies have already assessed changes in the brain and cognitive functions in relation to exercise: regular physical exercise causes changes in the working and structure of the brain.
The experts point out that these changes seem to have a certain specificity. The Harvard researcher supports the notion that "regular exercise improves output in tests that measure the state of the brain's executive functions and increases the amount of grey matter and prefrontal connections."
Inhibitory control is one of the executive functions of the brain and is basically the ability to suppress inadequate and non-conforming answers to an aim (the opposite of this would be impulsiveness), which makes modification or self-regulations of a behaviour possible.
With regards to losing weight and sustaining weight loss in the long run, various recent studies suggest that executive functions such as inhibitory control and optimal functioning of the brain's prefrontal areas could be the key to success. This success is mainly the fruit of a behavioural change. Inhibitory control could also help to prevent weight gain in healthy people.
The researcher outlines that "in time, exercise produces a potentiating effect of executive functions including the ability for inhibitory control, which can help us to resist the many temptations that we are faced with everyday in a society where food, especially hypercaloric food, is more and more omnipresent."
A healthy diet and the right amount of exercise are key players in treating and preventing obesity but we still know little about the relationship both factors have with each other. A new study now reveals that an increase in physical activity is linked to an improvement in diet quality.
Many questions arise when trying to lose weight. Would it be better to start on a diet and then do exercise, or the other way around? And how much does one compensate the other?
The data from epidemiological studies suggest that tendencies towards a healthy diet and the right amount of physical exercise often come hand in hand. Furthermore, an increase in physical activity is usually linked to a parallel improvement in diet quality.
Exercise also brings benefits such as an increase in sensitivity to physiological signs of fullness. This not only means that appetite can be controlled better but it also modifies hedonic responses to food stimuli. Therefore, benefits can be classified as those that occur in the short term (of metabolic predominance) and those that are seen in the long term (of behavioural predominance).
According to Alonso Alonso, "physical exercise seems to encourage a healthy diet. In fact, when exercise is added to a weight-loss diet, treatment of obesity is more successful and the diet is adhered to in the long run."
The authors of the study state how important it is for social policy to encourage and facilitate sport and physical exercise amongst the population. This should be present in both schools and our urban environment or daily lives through the use of public transport or availability of pedestrianised areas and sports facilities.
Exercise modifies the brain
Eating and physical activity are behaviours and are therefore influenced by cognitive processes that are a result of activity in different areas of the brain. Previous studies have already assessed changes in the brain and cognitive functions in relation to exercise: regular physical exercise causes changes in the working and structure of the brain.
The experts point out that these changes seem to have a certain specificity. The Harvard researcher supports the notion that "regular exercise improves output in tests that measure the state of the brain's executive functions and increases the amount of grey matter and prefrontal connections."
Inhibitory control is one of the executive functions of the brain and is basically the ability to suppress inadequate and non-conforming answers to an aim (the opposite of this would be impulsiveness), which makes modification or self-regulations of a behaviour possible.
With regards to losing weight and sustaining weight loss in the long run, various recent studies suggest that executive functions such as inhibitory control and optimal functioning of the brain's prefrontal areas could be the key to success. This success is mainly the fruit of a behavioural change. Inhibitory control could also help to prevent weight gain in healthy people.
The researcher outlines that "in time, exercise produces a potentiating effect of executive functions including the ability for inhibitory control, which can help us to resist the many temptations that we are faced with everyday in a society where food, especially hypercaloric food, is more and more omnipresent."
The scoop on the dangers of snow shoveling
Ω
Urban legend warns shoveling snow causes heart attacks, and the legend seems all too accurate, especially for male wintery excavators with a family history of premature cardiovascular disease. However, until recently this warning was based on anecdotal reports.
Two of the most important cardiology associations in the US include snow -shoveling on their websites as a high risk physical activity, but all the citation references indicate that this warning was based one or two incidents.
“We thought that this evidence should not be enough to convince us that snow -shoveling is potentially dangerous, ” says Adrian Baranchuk, a professor in Queen’s School of Medicine and a cardiologist at Kingston General Hospital.
Dr. Baranchuk and his team retrospectively reviewed KGH patient records from the two previous winter seasons and discovered that of the 500 patients who came to the hospital with heart problems during this period, 7 per cent (35 patients) had started experiencing symptoms while shoveling snow.
“That is a huge number,” says Dr. Baranchuk. “7 per cent of anything in medicine is a significant proportion. Also, if we take into account that we may have missed some patients who did not mention that they were shoveling snow around the time that the episode occurred, that number could easily double.”
The team also identified three main factors that put individuals at a high risk when shoveling snow. The number one factor was gender (31 of the 35 patients were male), the second was a family history of premature coronary artery disease (20 of the 35 patients), and the third was smoking (16 out of 35 patients). The second two factors may carry much more weight than the first, however, since the team could not correct for high rate of snow shoveling among men in their sample.
A history of regularly taking four or more cardiac medications was found to be preventative.
Urban legend warns shoveling snow causes heart attacks, and the legend seems all too accurate, especially for male wintery excavators with a family history of premature cardiovascular disease. However, until recently this warning was based on anecdotal reports.
Two of the most important cardiology associations in the US include snow -shoveling on their websites as a high risk physical activity, but all the citation references indicate that this warning was based one or two incidents.
“We thought that this evidence should not be enough to convince us that snow -shoveling is potentially dangerous, ” says Adrian Baranchuk, a professor in Queen’s School of Medicine and a cardiologist at Kingston General Hospital.
Dr. Baranchuk and his team retrospectively reviewed KGH patient records from the two previous winter seasons and discovered that of the 500 patients who came to the hospital with heart problems during this period, 7 per cent (35 patients) had started experiencing symptoms while shoveling snow.
“That is a huge number,” says Dr. Baranchuk. “7 per cent of anything in medicine is a significant proportion. Also, if we take into account that we may have missed some patients who did not mention that they were shoveling snow around the time that the episode occurred, that number could easily double.”
The team also identified three main factors that put individuals at a high risk when shoveling snow. The number one factor was gender (31 of the 35 patients were male), the second was a family history of premature coronary artery disease (20 of the 35 patients), and the third was smoking (16 out of 35 patients). The second two factors may carry much more weight than the first, however, since the team could not correct for high rate of snow shoveling among men in their sample.
A history of regularly taking four or more cardiac medications was found to be preventative.
Thanksgiving: BPA for Families Using Canned Foods
Ω
A new report released today by the Breast Cancer Fund documents the presence of the toxic chemical bisphenol A (BPA) in canned foods used to prepare a typical Thanksgiving meal.
Plus, Myths and Facts about BPA in Canned Foods and Recipes for a BPA-Free Thanksgiving at www.breastcancerfund.org/thanksgiving
A new report released today by the Breast Cancer Fund documents the presence of the toxic chemical bisphenol A (BPA) in canned foods used to prepare a typical Thanksgiving meal.
The report, "BPA in Thanksgiving Canned Food," tested Campbell's Cream of Mushroom Soup, Campbell's Turkey Gravy, Carnation Evaporated Milk (by Nestle), Del Monte Fresh Cut Sweet Corn (Cream Style), Green Giant Cut Green Beans (by General Mills), Libby's Pumpkin (by Nestle), and Ocean Spray Jellied Cranberry Sauce. Single servings of almost half of the products tested had levels of BPA comparable to levels that laboratory studies have linked to adverse health effects.
"Preparing your Thanksgiving dinner with these products can deliver a concerning level of BPA," said Jeanne Rizzo, president and CEO of the Breast Cancer Fund. "How many more Thanksgivings will families have to worry about this uninvited guest before manufacturers finally decide to take it out of cans?"
BPA is used to make, among other things, the epoxy-resin linings of metal food cans. The lining forms a barrier between the metal and the food which helps to prevent bacterial contamination. However, the toxic chemical can leach from the resin and make its way into food. BPA has been linked in laboratory studies to adverse health effects such as breast and prostate cancer, infertility, early puberty in girls, type-2 diabetes, obesity and attention deficit hyperactivity disorder.
For this report, the Breast Cancer Fund sent 28 canned food items—four cans of each product tested—to Anresco Laboratories, an independent testing laboratory in San Francisco. The testing revealed tremendous variability among cans of the same product made by the same company, which is consistent with other product testing data.
For instance, BPA levels in Del Monte creamed corn ranged from non-detectable to 221 parts per billion, and levels in Campbell's Turkey Gravy ranged from 5 to 125 ppb. According to scientists at the Breast Cancer Fund, these inconsistencies might be explained by variations in the canning processes across facilities and batches, as well as storage and transportation conditions.
"Consumers have no way of assessing BPA levels just by looking at cans on supermarket shelves," said Gretchen Lee Salter, policy manager at the Breast Cancer Fund. "The findings of this report highlight the urgent need to remove BPA from food packaging so that shoppers can be confident that the food they are purchasing is safe for their families—not only on Thanksgiving, but every day."
The tests detected no BPA in any of the four cans of Ocean Spray Cranberry Sauce. The company has stated that while it does use BPA in its cans, independent tests also indicate no leaching of BPA into the food.
"We know from recent research that a BPA meal creates a spike of this estrogenic chemical in the blood," said William Goodson, M.D., a breast cancer surgeon and senior clinical research scientist at California Pacific Medical Center Research Institute, who in September published a study showing that BPA causes non-cancerous cells to grow and survive like cancer cells. "Natural hormones work by spikes, so this is exactly what you don't want, especially in young kids, who shouldn't have any estrogenic spikes at all."
As part of the Breast Cancer Fund's Cans Not Cancer campaign, consumers have sent more than 50,000 letters to canned food manufacturers urging them to get BPA out of canned foods and replaced with a safer alternative, and many are beginning to pay attention. A number of companies including some of the can manufacturers featured in this report, such as General Mills and Nestle, have announced that they are working toward alternatives to BPA in canned foods. However, not all of the manufacturers are disclosing the alternative they are exploring. It is imperative that manufacturers are transparent about these alternatives and ensure they are safe.
At the public policy level, 11 states have banned BPA from baby bottles and sippy cups, and three of those states have also banned it from infant formula and baby food. The Breast Cancer Fund is also supporting pending federal legislation authored by Rep. Ed Markey, D-Mass., that would ban BPA from all food and beverage containers including canned foods.
The immediate solution for those preparing Thanksgiving dinner is to seek alternatives to canned foods. Visit www.breastcancerfund.org/thanksgiving for easy recipes for a can-free Thanksgiving meal.
Also available at www.breastcancerfund.org/thanksgiving are the full report and Myths and Facts about BPA in Canned Foods, combating the common industry arguments in favor of BPA.
Tuesday, November 22, 2011
Coffee may protect against endometrial cancer
Ω
Long-term coffee consumption may be associated with a reduced risk for endometrial cancer, according to a recent study in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.
Edward Giovannucci, M.D., Sc.D., professor of nutrition and epidemiology at the Harvard School of Public Health, said coffee is emerging as a protective agent in cancers that are linked to obesity, estrogen and insulin.
"Coffee has already been shown to be protective against diabetes due to its effect on insulin," said Giovannucci, a senior researcher on the study. "So we hypothesized that we'd see a reduction in some cancers as well."
Giovannucci, along with Youjin Je, a doctoral candidate in his lab, and colleagues observed cumulative coffee intake in relation to endometrial cancer in 67,470 women who enrolled in the Nurses' Health Study.
During the course of 26 years of follow-up, researchers documented 672 cases of endometrial cancer.
Drinking more than four cups of coffee per day was linked with a 25 percent reduced risk for endometrial cancer. Drinking between two and three cups per day was linked with a 7 percent reduced risk.
A similar link was seen in decaffeinated coffee, where drinking more than two cups per day was linked with a 22 percent reduced risk for endometrial cancer.
Giovannucci said he hopes this study will lead to further inquiries about the effect of coffee on cancer because in this and similar studies, coffee intake is self-selected and not randomized.
"Coffee has long been linked with smoking, and if you drink coffee and smoke, the positive effects of coffee are going to be more than outweighed by the negative effects of smoking," said Giovannucci. "However, laboratory testing has found that coffee has much more antioxidants than most vegetables and fruits."
Long-term coffee consumption may be associated with a reduced risk for endometrial cancer, according to a recent study in Cancer Epidemiology, Biomarkers & Prevention, a journal of the American Association for Cancer Research.
Edward Giovannucci, M.D., Sc.D., professor of nutrition and epidemiology at the Harvard School of Public Health, said coffee is emerging as a protective agent in cancers that are linked to obesity, estrogen and insulin.
"Coffee has already been shown to be protective against diabetes due to its effect on insulin," said Giovannucci, a senior researcher on the study. "So we hypothesized that we'd see a reduction in some cancers as well."
Giovannucci, along with Youjin Je, a doctoral candidate in his lab, and colleagues observed cumulative coffee intake in relation to endometrial cancer in 67,470 women who enrolled in the Nurses' Health Study.
During the course of 26 years of follow-up, researchers documented 672 cases of endometrial cancer.
Drinking more than four cups of coffee per day was linked with a 25 percent reduced risk for endometrial cancer. Drinking between two and three cups per day was linked with a 7 percent reduced risk.
A similar link was seen in decaffeinated coffee, where drinking more than two cups per day was linked with a 22 percent reduced risk for endometrial cancer.
Giovannucci said he hopes this study will lead to further inquiries about the effect of coffee on cancer because in this and similar studies, coffee intake is self-selected and not randomized.
"Coffee has long been linked with smoking, and if you drink coffee and smoke, the positive effects of coffee are going to be more than outweighed by the negative effects of smoking," said Giovannucci. "However, laboratory testing has found that coffee has much more antioxidants than most vegetables and fruits."
Consuming canned soup linked to greatly elevated levels of the chemical BPA
Ω
BPA, found in soup can lining, associated with adverse health effects in humans
A new study from researchers at the Harvard School of Public Health (HSPH) has found that a group of volunteers who consumed a serving of canned soup each day for five days had a more than 1,000% increase in urinary bisphenol A (BPA) concentrations compared with when the same individuals consumed fresh soup daily for five days. The study is one of the first to quantify BPA levels in humans after ingestion of canned foods.
The findings were published online November 22, 2011, in the Journal of the Medical Association (JAMA) and will appear in the November 23/30 print issue.
"Previous studies have linked elevated BPA levels with adverse health effects. The next step was to figure out how people are getting exposed to BPA. We've known for a while that drinking beverages that have been stored in certain hard plastics can increase the amount of BPA in your body. This study suggests that canned foods may be an even greater concern, especially given their wide use," said Jenny Carwile, a doctoral student in the Department of Epidemiology at HSPH and lead author of the study.
Exposure to the endocrine-disrupting chemical BPA, used in the lining of metal food and beverage cans, has been shown to interfere with reproductive development in animals and has been linked with cardiovascular disease, diabetes, and obesity in humans. In addition to the lining of food and beverage cans, BPA is also found in polycarbonate bottles (identified by the recycling number 7) and dentistry composites and sealants.
The researchers, led by Carwile and Karin Michels, associate professor in the Department of Epidemiology, set out to quantify whether canned-soup consumption would increase urinary BPA concentrations relative to eating fresh soup.
They recruited student and staff volunteers from HSPH. One group consumed a 12-ounce serving of vegetarian canned soup each day for five days; another group consumed 12 ounces of vegetarian fresh soup (prepared without canned ingredients) daily for five days. After a two-day "washout" period, the groups reversed their assignments.
Urine samples of the 75 volunteers taken during the testing showed that consumption of a serving of canned soup daily was associated with a 1,221% increase in BPA compared to levels in urine collected after consumption of fresh soup.
The researchers note that the elevation in urinary BPA concentrations may be temporary and that further research is needed to quantify its duration.
"The magnitude of the rise in urinary BPA we observed after just one serving of soup was unexpected and may be of concern among individuals who regularly consume foods from cans or drink several canned beverages daily. It may be advisable for manufacturers to consider eliminating BPA from can linings," said Michels, senior author of the study.
BPA, found in soup can lining, associated with adverse health effects in humans
A new study from researchers at the Harvard School of Public Health (HSPH) has found that a group of volunteers who consumed a serving of canned soup each day for five days had a more than 1,000% increase in urinary bisphenol A (BPA) concentrations compared with when the same individuals consumed fresh soup daily for five days. The study is one of the first to quantify BPA levels in humans after ingestion of canned foods.
The findings were published online November 22, 2011, in the Journal of the Medical Association (JAMA) and will appear in the November 23/30 print issue.
"Previous studies have linked elevated BPA levels with adverse health effects. The next step was to figure out how people are getting exposed to BPA. We've known for a while that drinking beverages that have been stored in certain hard plastics can increase the amount of BPA in your body. This study suggests that canned foods may be an even greater concern, especially given their wide use," said Jenny Carwile, a doctoral student in the Department of Epidemiology at HSPH and lead author of the study.
Exposure to the endocrine-disrupting chemical BPA, used in the lining of metal food and beverage cans, has been shown to interfere with reproductive development in animals and has been linked with cardiovascular disease, diabetes, and obesity in humans. In addition to the lining of food and beverage cans, BPA is also found in polycarbonate bottles (identified by the recycling number 7) and dentistry composites and sealants.
The researchers, led by Carwile and Karin Michels, associate professor in the Department of Epidemiology, set out to quantify whether canned-soup consumption would increase urinary BPA concentrations relative to eating fresh soup.
They recruited student and staff volunteers from HSPH. One group consumed a 12-ounce serving of vegetarian canned soup each day for five days; another group consumed 12 ounces of vegetarian fresh soup (prepared without canned ingredients) daily for five days. After a two-day "washout" period, the groups reversed their assignments.
Urine samples of the 75 volunteers taken during the testing showed that consumption of a serving of canned soup daily was associated with a 1,221% increase in BPA compared to levels in urine collected after consumption of fresh soup.
The researchers note that the elevation in urinary BPA concentrations may be temporary and that further research is needed to quantify its duration.
"The magnitude of the rise in urinary BPA we observed after just one serving of soup was unexpected and may be of concern among individuals who regularly consume foods from cans or drink several canned beverages daily. It may be advisable for manufacturers to consider eliminating BPA from can linings," said Michels, senior author of the study.
Low salt intake as bad as high
Ω
For years doctors have warned that too much salt is bad for your heart. Now a new McMaster University study suggests that both high and low levels of salt intake may put people with heart disease or diabetes at increased risk of cardiovascular complications.
The study, published in the Journal of the American Medical Association (JAMA) today, found that moderate salt intake was associated with the lowest risk of cardiovascular events, while a higher intake of sodium was associated with an increased risk of stroke, heart attack and other cardiovascular events and a low intake was associated with an increased risk of cardiovascular death and hospitalization for congestive heart failure.
The research, conducted by investigators in the Michael G. DeGroote School of Medicine at McMaster University and the Population Health Research Institute (PHRI) at McMaster and Hamilton Health Sciences, was co-led by Dr. Martin O'Donnell, an associate clinical professor of medicine, and Dr. Salim Yusuf, a professor of medicine and executive director of the PHRI.
"This research addresses an important population health issue – the association between salt intake and cardiovascular disease," said O'Donnell, who is also appointed at the Health Research Board Clinical Research Facility, National University of Ireland.
"In general, previous observational studies have either reported a positive association, no association or an inverse association between sodium intake and heart disease and stroke. This has resulted in a lot of controversy. Our study is the first to report a J-shaped association between sodium intake and cardiovascular disease, which may explain why previous studies have found different results."
For the McMaster observational study, the researchers examined 28,880 people at increased risk of heart disease from clinical trials conducted between 2001 and 2008. The researchers estimated 24-hour urinary sodium and potassium excretion from a morning fasting urine sample. Follow-up found more than 4,500 cardiovascular events occurred, making this one of the largest studies examining the relationship between sodium excretion (a surrogate measure of sodium consumption), as well as potassium excretion and cardiovascular events. Extensive and careful statistical analytic methods were used to determine the association of urinary sodium and potassium with cardiovascular events, in particular heart attack, stroke, hospitalization for congestive heart failure and death.
Compared with moderate sodium excretion (between 4 to 5.99 grams per day), the researchers found that sodium excretion of greater than seven grams per day was associated with an increased risk of all cardiovascular events, and sodium excretion of less than three grams per day was associated with an increased risk of cardiovascular death and hospitalization for congestive heart failure.
The findings call into question current guidelines for salt intake, which recommend less than 2.3 grams (or 2,300 mg) per day. The guidelines are mostly based on previous clinical trials that found blood pressure is lowered modestly when sodium intake is reduced to this level (which was also found in the present study). However, there are no large studies looking at whether such low levels of sodium intake reduce the incidence of heart attacks and stroke.
Clarifying the optimal daily intake of sodium is particularly important in patients with established heart disease, as they may be especially vulnerable to the cardiovascular effects of very high- and low-salt intake and are most likely to receive recommendations on restricting sodium in their diets, the authors concluded.
"Our study confirms the association between high-sodium intake and cardiovascular disease. Our findings highlight the importance of reducing salt intake in those consuming high-salt diets and the need for reducing sodium content in manufactured foods that are high in salt," said Yusuf, who is also vice-president of research, Hamilton Health Sciences.
"However, for those with moderate (average) intake, whether further reduction of salt in the diet will be beneficial is an open question. We believe that large clinical trials are the most reliable way to determine if reducing sodium intake to lower levels is of benefit."
For years doctors have warned that too much salt is bad for your heart. Now a new McMaster University study suggests that both high and low levels of salt intake may put people with heart disease or diabetes at increased risk of cardiovascular complications.
The study, published in the Journal of the American Medical Association (JAMA) today, found that moderate salt intake was associated with the lowest risk of cardiovascular events, while a higher intake of sodium was associated with an increased risk of stroke, heart attack and other cardiovascular events and a low intake was associated with an increased risk of cardiovascular death and hospitalization for congestive heart failure.
The research, conducted by investigators in the Michael G. DeGroote School of Medicine at McMaster University and the Population Health Research Institute (PHRI) at McMaster and Hamilton Health Sciences, was co-led by Dr. Martin O'Donnell, an associate clinical professor of medicine, and Dr. Salim Yusuf, a professor of medicine and executive director of the PHRI.
"This research addresses an important population health issue – the association between salt intake and cardiovascular disease," said O'Donnell, who is also appointed at the Health Research Board Clinical Research Facility, National University of Ireland.
"In general, previous observational studies have either reported a positive association, no association or an inverse association between sodium intake and heart disease and stroke. This has resulted in a lot of controversy. Our study is the first to report a J-shaped association between sodium intake and cardiovascular disease, which may explain why previous studies have found different results."
For the McMaster observational study, the researchers examined 28,880 people at increased risk of heart disease from clinical trials conducted between 2001 and 2008. The researchers estimated 24-hour urinary sodium and potassium excretion from a morning fasting urine sample. Follow-up found more than 4,500 cardiovascular events occurred, making this one of the largest studies examining the relationship between sodium excretion (a surrogate measure of sodium consumption), as well as potassium excretion and cardiovascular events. Extensive and careful statistical analytic methods were used to determine the association of urinary sodium and potassium with cardiovascular events, in particular heart attack, stroke, hospitalization for congestive heart failure and death.
Compared with moderate sodium excretion (between 4 to 5.99 grams per day), the researchers found that sodium excretion of greater than seven grams per day was associated with an increased risk of all cardiovascular events, and sodium excretion of less than three grams per day was associated with an increased risk of cardiovascular death and hospitalization for congestive heart failure.
The findings call into question current guidelines for salt intake, which recommend less than 2.3 grams (or 2,300 mg) per day. The guidelines are mostly based on previous clinical trials that found blood pressure is lowered modestly when sodium intake is reduced to this level (which was also found in the present study). However, there are no large studies looking at whether such low levels of sodium intake reduce the incidence of heart attacks and stroke.
Clarifying the optimal daily intake of sodium is particularly important in patients with established heart disease, as they may be especially vulnerable to the cardiovascular effects of very high- and low-salt intake and are most likely to receive recommendations on restricting sodium in their diets, the authors concluded.
"Our study confirms the association between high-sodium intake and cardiovascular disease. Our findings highlight the importance of reducing salt intake in those consuming high-salt diets and the need for reducing sodium content in manufactured foods that are high in salt," said Yusuf, who is also vice-president of research, Hamilton Health Sciences.
"However, for those with moderate (average) intake, whether further reduction of salt in the diet will be beneficial is an open question. We believe that large clinical trials are the most reliable way to determine if reducing sodium intake to lower levels is of benefit."
L-arginine: fit, young, athletic men - no advantage
Ω
Popular supplement goes under the microscope, reveals no metabolic or hormonal enhancement for athletes at rest
One of the most recent, popular supplements for athletes looking to boost performance comes in the form of a naturally-occurring amino acid called L-arginine.
The reason for its popularity is twofold says Scott Forbes, a doctoral student in exercise physiology. "First, L-arginine is a precursor for nitric oxide that is known to improve blood flow, which in turn may aid the delivery of important nutrients to working muscles and assist with metabolic waste product removal. Secondly, L-arginine has been shown to increase growth hormone levels in the blood."
The benefits of growth hormone are diverse, including increasing the use of fat as a fuel as well as insulin and insulin-growth factor-1 (IGF-1) levels. However, most of the research conducted on L-arginine has been in a clinical setting and the benefits for physically active individuals are not as established. In some cases they are conflicting.
"One of the reasons for this is that the amount an individual has to consume has not been clearly established and this information is rarely provided by the manufacturers of such products," explains Forbes, a doctoral student in exercise physiology.
For Forbes it was a theory worth testing – and he wanted to test two different L-arginine doses on healthy, athletic men – the group most likely to purchase this readily-available supplement.
"L-arginine is interesting for a few reasons," says Forbes. "It can increase growth hormone response, and so can increase muscle mass. Also it has an impact on insulin, which is another anabolic hormone. A recent hot topic has been about nitric oxide as a vasodilator. The theory is that if you can vasodilate your arteries you can potentially enhance blood flow to the muscles and enhance nutrient delivery and waste product removal."
L-arginine is also often prescribed for older adults with cardiovascular disease, endothelial dysfunction or hypertension for its vasodilation properties and is rarely studied in younger, more vigorous populations.
For this study, Forbes recruited 14, active, physically fit men (age: 25±5yrs; weight: 78.0±8.5kg; height: 179.4±4.7cm), who were free of nutritional supplements, to examine a low and high dose of oral L-arginine on blood L-arginine, markers of nitric oxide, growth hormone, insulin, and insulin-like growth factor-1. In the double-blind, randomized, placebo-controlled study participants were first pre-screened, completing a one-day food record which was analyzed for carbohydrates, protein and fat consumption and caloric intake, then required to follow a modified diet to regulate intake of food and water prior to being dosed with L-arginine.
"After a 10-hour overnight fast, and no breakfast, we gave them a different dose of L-arginine – either .075 g per kilogram of body mass for the low dose, .15 g per kg of body mass for the high dose, or a placebo," says Forbes.
Blood samples were drawn with the athlete at rest, every half hour for three hours after the L-arginine or placebo dose. The reason explains Forbes, is that "Previous studies show that two hours after consumption L-arginine tends to reach baseline again."
What Forbes found was that in healthy, young, physically active males the two different doses significantly elevated L-arginine concentrations in the blood at rest, and both a low dose and a high dose were equally effective in doing so, but neither dose promoted a significant increase in nitric oxide, growth hormone, insulin, or insulin-like growth factor-1.
So, according to the study, it appears that L-arginine's impact depends on one's current health status: the more healthy and athletic the person, the less they'll benefit from it.
Now that he's established how L-arginine impacts the fit, young body at rest, he's embarked on two more studies – one with strength-trained athletes and one with aerobically-trained athletes – cyclists in this case – to look at the impacts of L-arginine on the body during exercise. "This time we're looking at the effects of supplements under two extremes: aerobic and strength exercise.
"There's a lot of money in nutritional supplements," he adds. "The industry might not be too happy when they see the results at rest, but who knows, it may be different with exercise."
Forbes has completed both of the exercise studies and hopes to publish the results in the near future.
Popular supplement goes under the microscope, reveals no metabolic or hormonal enhancement for athletes at rest
One of the most recent, popular supplements for athletes looking to boost performance comes in the form of a naturally-occurring amino acid called L-arginine.
The reason for its popularity is twofold says Scott Forbes, a doctoral student in exercise physiology. "First, L-arginine is a precursor for nitric oxide that is known to improve blood flow, which in turn may aid the delivery of important nutrients to working muscles and assist with metabolic waste product removal. Secondly, L-arginine has been shown to increase growth hormone levels in the blood."
The benefits of growth hormone are diverse, including increasing the use of fat as a fuel as well as insulin and insulin-growth factor-1 (IGF-1) levels. However, most of the research conducted on L-arginine has been in a clinical setting and the benefits for physically active individuals are not as established. In some cases they are conflicting.
"One of the reasons for this is that the amount an individual has to consume has not been clearly established and this information is rarely provided by the manufacturers of such products," explains Forbes, a doctoral student in exercise physiology.
For Forbes it was a theory worth testing – and he wanted to test two different L-arginine doses on healthy, athletic men – the group most likely to purchase this readily-available supplement.
"L-arginine is interesting for a few reasons," says Forbes. "It can increase growth hormone response, and so can increase muscle mass. Also it has an impact on insulin, which is another anabolic hormone. A recent hot topic has been about nitric oxide as a vasodilator. The theory is that if you can vasodilate your arteries you can potentially enhance blood flow to the muscles and enhance nutrient delivery and waste product removal."
L-arginine is also often prescribed for older adults with cardiovascular disease, endothelial dysfunction or hypertension for its vasodilation properties and is rarely studied in younger, more vigorous populations.
For this study, Forbes recruited 14, active, physically fit men (age: 25±5yrs; weight: 78.0±8.5kg; height: 179.4±4.7cm), who were free of nutritional supplements, to examine a low and high dose of oral L-arginine on blood L-arginine, markers of nitric oxide, growth hormone, insulin, and insulin-like growth factor-1. In the double-blind, randomized, placebo-controlled study participants were first pre-screened, completing a one-day food record which was analyzed for carbohydrates, protein and fat consumption and caloric intake, then required to follow a modified diet to regulate intake of food and water prior to being dosed with L-arginine.
"After a 10-hour overnight fast, and no breakfast, we gave them a different dose of L-arginine – either .075 g per kilogram of body mass for the low dose, .15 g per kg of body mass for the high dose, or a placebo," says Forbes.
Blood samples were drawn with the athlete at rest, every half hour for three hours after the L-arginine or placebo dose. The reason explains Forbes, is that "Previous studies show that two hours after consumption L-arginine tends to reach baseline again."
What Forbes found was that in healthy, young, physically active males the two different doses significantly elevated L-arginine concentrations in the blood at rest, and both a low dose and a high dose were equally effective in doing so, but neither dose promoted a significant increase in nitric oxide, growth hormone, insulin, or insulin-like growth factor-1.
So, according to the study, it appears that L-arginine's impact depends on one's current health status: the more healthy and athletic the person, the less they'll benefit from it.
Now that he's established how L-arginine impacts the fit, young body at rest, he's embarked on two more studies – one with strength-trained athletes and one with aerobically-trained athletes – cyclists in this case – to look at the impacts of L-arginine on the body during exercise. "This time we're looking at the effects of supplements under two extremes: aerobic and strength exercise.
"There's a lot of money in nutritional supplements," he adds. "The industry might not be too happy when they see the results at rest, but who knows, it may be different with exercise."
Forbes has completed both of the exercise studies and hopes to publish the results in the near future.
PHYSICAL ACTIVITY IMPACTS OVERALL QUALITY OF SLEEP
Ω
People sleep significantly better and feel more alert during the day if they get at least 150 minutes of exercise a week, a new study concludes.
A nationally representative sample of more than 2,600 men and women, ages 18-85, found that 150 minutes of moderate to vigorous activity a week, which is the national guideline, provided a 65 percent improvement in sleep quality. People also said they felt less sleepy during the day, compared to those with less physical activity.
The study, out in the December issue of the journal Mental Health and Physical Activity, lends more evidence to mounting research showing the importance of exercise to a number of health factors. Among adults in the United States, about 35 to 40 percent of the population has problems with falling asleep or with daytime sleepiness.
“We were using the physical activity guidelines set forth for cardiovascular health, but it appears that those guidelines might have a spillover effect to other areas of health,” said Brad Cardinal, a professor of exercise science at Oregon State University and one of the study’s authors.
“Increasingly, the scientific evidence is encouraging as regular physical activity may serve as a non-pharmaceutical alternative to improve sleep.”
After controlling for age, BMI (Body Mass Index), health status, smoking status, and depression, the relative risk of often feeling overly sleepy during the day compared to never feeling overly sleepy during the day decreased by 65 percent for participants meeting physical activity guidelines.
Similar results were also found for having leg cramps while sleeping (68 percent less likely) and having difficulty concentrating when tired (45 percent decrease).
Paul Loprinzi, an assistant professor at Bellarmine University is lead author of the study, which was conducted while he was a doctoral student in Cardinal’s lab at OSU. He said it is the first study to examine the relationship between accelerometer-measured physical activity and sleep while utilizing a nationally representative sample of adults of all ages.
‘Our findings demonstrate a link between regular physical activity and perceptions of sleepiness during the day, which suggests that participation in physical activity on a regular basis may positively influence an individual's productivity at work, or in the case of a student, influence their ability to pay attention in class,” he said.
Cardinal said past studies linking physical activity and sleep used only self-reports of exercise. The danger with this is that many people tend to overestimate the amount of activity they do, he said.
He added that the take-away for consumers is to remember that exercise has a number of health benefits, and that can include helping feel alert and awake.
“Physical activity may not just be good for the waistline and heart, but it also can help you sleep,” Cardinal said. “There are trade-offs. It may be easier when you are tired to skip the workout and go to sleep, but it may be beneficial for your long-term health to make the hard decision and get your exercise.”
People sleep significantly better and feel more alert during the day if they get at least 150 minutes of exercise a week, a new study concludes.
A nationally representative sample of more than 2,600 men and women, ages 18-85, found that 150 minutes of moderate to vigorous activity a week, which is the national guideline, provided a 65 percent improvement in sleep quality. People also said they felt less sleepy during the day, compared to those with less physical activity.
The study, out in the December issue of the journal Mental Health and Physical Activity, lends more evidence to mounting research showing the importance of exercise to a number of health factors. Among adults in the United States, about 35 to 40 percent of the population has problems with falling asleep or with daytime sleepiness.
“We were using the physical activity guidelines set forth for cardiovascular health, but it appears that those guidelines might have a spillover effect to other areas of health,” said Brad Cardinal, a professor of exercise science at Oregon State University and one of the study’s authors.
“Increasingly, the scientific evidence is encouraging as regular physical activity may serve as a non-pharmaceutical alternative to improve sleep.”
After controlling for age, BMI (Body Mass Index), health status, smoking status, and depression, the relative risk of often feeling overly sleepy during the day compared to never feeling overly sleepy during the day decreased by 65 percent for participants meeting physical activity guidelines.
Similar results were also found for having leg cramps while sleeping (68 percent less likely) and having difficulty concentrating when tired (45 percent decrease).
Paul Loprinzi, an assistant professor at Bellarmine University is lead author of the study, which was conducted while he was a doctoral student in Cardinal’s lab at OSU. He said it is the first study to examine the relationship between accelerometer-measured physical activity and sleep while utilizing a nationally representative sample of adults of all ages.
‘Our findings demonstrate a link between regular physical activity and perceptions of sleepiness during the day, which suggests that participation in physical activity on a regular basis may positively influence an individual's productivity at work, or in the case of a student, influence their ability to pay attention in class,” he said.
Cardinal said past studies linking physical activity and sleep used only self-reports of exercise. The danger with this is that many people tend to overestimate the amount of activity they do, he said.
He added that the take-away for consumers is to remember that exercise has a number of health benefits, and that can include helping feel alert and awake.
“Physical activity may not just be good for the waistline and heart, but it also can help you sleep,” Cardinal said. “There are trade-offs. It may be easier when you are tired to skip the workout and go to sleep, but it may be beneficial for your long-term health to make the hard decision and get your exercise.”
Thursday, November 17, 2011
Taking Supplements = Taking Risks
Ω
The lack of evidence on multivitamin health benefits is no impediment to their widespread popularity, with over half the U.S. population popping such pills. This translates into a $27 billion industry, which lures consumers with the illusory promise of better health. But shocking new research suggests taking multivitamins might have the opposite effect -- not simply on the metabolic level, but on a metaphysical one: promoting a false sense of invulnerability that actually leads users to engage in riskier behaviors.
Taiwanese researchers conducted an experiment in which they gave placebos to 82 adults (45 women, 37 men, average age 31). Half of this group was led to believe that the placebo they were taking was a multivitamin. After one week, all participants took surveys regarding their inclinations towards various healthy vs. less healthy behaviors. The results were astounding. Those subjects thinking they were taking multivitamins registered a 44% higher tendency to engage in hedonistic activities (e.g., casual sex, sunbathing, partying, binge drinking), as well as a 61% increased preference for all-you-can-eat buffets over healthy meals. Compared to the placebo group, the "multivitamin" group not only reported exercising 14% less, they were 66% more likely to walk the shortest distance to their goal over a given time.
The authors conclude that people relying on a multivitamin pay a hidden price, believing they have greater invulnerability and so adopt lazy, riskier behaviors that may actually lead to the exact opposite health outcomes they desire. With regard to direct health impact, a "state-of-the-science" NIH panel found insufficient evidence to recommend multivitamin usage, while the National Cancer Institute actually found that men who take more than seven multivitamins a week are a third more likely to experience advanced prostate cancer. The American Heart Association urges people to forgo antioxidant supplements in favor of fruit and vegetables to minimize cardiovascular disease risk.
Antioxidant pills may even block certain metabolic benefits of exercise.
In a recent German study, 40 young male volunteers engaged in about an hour and a half of intense exercise -- running, cycling, weight-lifting -- five days a week.As expected, the regimen yielded various health benefits, including improved ability to control blood sugar, thus reducing diabetes risk.But when the men took antioxidant supplements -- 400 IU of vitamin E and 1,000 mg of vitamin C -- there was NO improvement in insulin sensitivity.Why? The pills seem to displace the body's own natural antioxidant systems, which otherwise neutralize the oxidative damage caused by oxygen radicals produced during exercise.
These findings add to the mountain of evidence that reliance on supplements either offers no benefits or even poses specific health risks. For example, athletes and others take glucosamine to relieve joint pain, but research shows most commercial supplements are ineffective, while the safety of large doses remains uncertain
The lack of evidence on multivitamin health benefits is no impediment to their widespread popularity, with over half the U.S. population popping such pills. This translates into a $27 billion industry, which lures consumers with the illusory promise of better health. But shocking new research suggests taking multivitamins might have the opposite effect -- not simply on the metabolic level, but on a metaphysical one: promoting a false sense of invulnerability that actually leads users to engage in riskier behaviors.
Taiwanese researchers conducted an experiment in which they gave placebos to 82 adults (45 women, 37 men, average age 31). Half of this group was led to believe that the placebo they were taking was a multivitamin. After one week, all participants took surveys regarding their inclinations towards various healthy vs. less healthy behaviors. The results were astounding. Those subjects thinking they were taking multivitamins registered a 44% higher tendency to engage in hedonistic activities (e.g., casual sex, sunbathing, partying, binge drinking), as well as a 61% increased preference for all-you-can-eat buffets over healthy meals. Compared to the placebo group, the "multivitamin" group not only reported exercising 14% less, they were 66% more likely to walk the shortest distance to their goal over a given time.
The authors conclude that people relying on a multivitamin pay a hidden price, believing they have greater invulnerability and so adopt lazy, riskier behaviors that may actually lead to the exact opposite health outcomes they desire. With regard to direct health impact, a "state-of-the-science" NIH panel found insufficient evidence to recommend multivitamin usage, while the National Cancer Institute actually found that men who take more than seven multivitamins a week are a third more likely to experience advanced prostate cancer. The American Heart Association urges people to forgo antioxidant supplements in favor of fruit and vegetables to minimize cardiovascular disease risk.
Antioxidant pills may even block certain metabolic benefits of exercise.
In a recent German study, 40 young male volunteers engaged in about an hour and a half of intense exercise -- running, cycling, weight-lifting -- five days a week.As expected, the regimen yielded various health benefits, including improved ability to control blood sugar, thus reducing diabetes risk.But when the men took antioxidant supplements -- 400 IU of vitamin E and 1,000 mg of vitamin C -- there was NO improvement in insulin sensitivity.Why? The pills seem to displace the body's own natural antioxidant systems, which otherwise neutralize the oxidative damage caused by oxygen radicals produced during exercise.
These findings add to the mountain of evidence that reliance on supplements either offers no benefits or even poses specific health risks. For example, athletes and others take glucosamine to relieve joint pain, but research shows most commercial supplements are ineffective, while the safety of large doses remains uncertain
Study Affirms ‘Mediterranean Diet’ Improves Heart Health
Ω
A team of Johns Hopkins researchers has uncovered further evidence of the benefits of a balanced diet that replaces white bread and pasta carbohydrates with unsaturated fat from avocados, olive oil and nuts — foods typical of the so-called “Mediterranean diet.”
In a report prepared for the American Heart Association’s scientific sessions in Orlando next week, the Johns Hopkins investigators say swapping out certain foods can improve heart health in those at risk for cardiovascular disease, even if the dietary changes aren’t coupled with weight loss.
“The introduction of the right kind of fat into a healthy diet is another tool to reduce the risk of future heart disease,” says Meghana Gadgil, M.D., M.P.H., a postdoctoral fellow in the Division of General Internal Medicine at the Johns Hopkins University School of Medicine who will be presenting the research.
Gadgil and her colleagues analyzed data from the OmniHeart Trial, which studied the cardiovascular effects of three different balanced diets on 164 people with mild hypertension but no diabetes. The researchers compared the body’s ability to regulate blood sugar and maintain healthy insulin levels while on a carbohydrate-rich diet, a protein-rich diet and a diet rich in unsaturated fats. People whose bodies fail to effectively use insulin usually develop type 2 diabetes, which is a major risk factor for heart disease.
The researchers found that a generally balanced diet higher in unsaturated fats such as those in avocados, olive oil and nuts improves insulin use significantly more than a diet high in carbohydrates, particularly such refined carbs as white bread and pasta. The preferred diet is very similar to the Mediterranean diet, inspired by the foods of southern Italy and Greece and emphasizing healthy fats, fruits and vegetables.
Each participant in the study was fed each of the three diets for six weeks in a row, with two to four weeks off in between. Blood samples were collected after fasting periods in weeks four and six of each diet, and used to monitor insulin and glucose levels. The study was designed to keep participants at their starting weights. “A lot of studies have looked at how the body becomes better at using insulin when you lose weight,” Gadgil says. “We kept the weight stable so we could isolate the effects of the macronutrients. What we found is that you can begin to see a beneficial impact on heart health even before weight loss.”
Other Hopkins resea
A team of Johns Hopkins researchers has uncovered further evidence of the benefits of a balanced diet that replaces white bread and pasta carbohydrates with unsaturated fat from avocados, olive oil and nuts — foods typical of the so-called “Mediterranean diet.”
In a report prepared for the American Heart Association’s scientific sessions in Orlando next week, the Johns Hopkins investigators say swapping out certain foods can improve heart health in those at risk for cardiovascular disease, even if the dietary changes aren’t coupled with weight loss.
“The introduction of the right kind of fat into a healthy diet is another tool to reduce the risk of future heart disease,” says Meghana Gadgil, M.D., M.P.H., a postdoctoral fellow in the Division of General Internal Medicine at the Johns Hopkins University School of Medicine who will be presenting the research.
Gadgil and her colleagues analyzed data from the OmniHeart Trial, which studied the cardiovascular effects of three different balanced diets on 164 people with mild hypertension but no diabetes. The researchers compared the body’s ability to regulate blood sugar and maintain healthy insulin levels while on a carbohydrate-rich diet, a protein-rich diet and a diet rich in unsaturated fats. People whose bodies fail to effectively use insulin usually develop type 2 diabetes, which is a major risk factor for heart disease.
The researchers found that a generally balanced diet higher in unsaturated fats such as those in avocados, olive oil and nuts improves insulin use significantly more than a diet high in carbohydrates, particularly such refined carbs as white bread and pasta. The preferred diet is very similar to the Mediterranean diet, inspired by the foods of southern Italy and Greece and emphasizing healthy fats, fruits and vegetables.
Each participant in the study was fed each of the three diets for six weeks in a row, with two to four weeks off in between. Blood samples were collected after fasting periods in weeks four and six of each diet, and used to monitor insulin and glucose levels. The study was designed to keep participants at their starting weights. “A lot of studies have looked at how the body becomes better at using insulin when you lose weight,” Gadgil says. “We kept the weight stable so we could isolate the effects of the macronutrients. What we found is that you can begin to see a beneficial impact on heart health even before weight loss.”
Other Hopkins resea
Tuesday, November 15, 2011
Moderate drinking and cardiovascular health: beer
Ω
A study conducted by research laboratories at Fondazione 'Giovanni Paolo II' in Italy shows that beer, like wine, can reduce the risk of cardiovascular disease
Beer could stand up alongside wine regarding positive effects on cardiovascular health. This is the conclusion of a study conducted by Research Laboratories at the Fondazione di Ricerca e Cura "Giovanni Paolo II", in Campobasso, Italy. Both for wine and beer the key is moderate and regular drinking.
The research, published today on line by the European Journal of Epidemiology, using the statistic approach of meta-analysis, pooled different scientific studies conducted worldwide in previous years to achieve a general result. This way it has been possible to examine data concerning over 200,000 people, for whom alcohol drinking habits were associated with cardiovascular disease.
Results confirm what was already known about wine: a moderate consumption (approximately two glasses per day for men and one for women) can lower the risk of cardiovascular disease, up to 31% less when comparing to non drinkers. What this research adds are new data on beer. For the first time, in fact, evidence about dose-dependent effect is shown for this beverage. Maximum protection is observed, for a beer containing 5% of alcohol, with a consumption of slightly more than an English pint a day.
"In our research – explains Simona Costanzo, first author of the paper - we considered wine and beer separately: you first observe a reduction in cardiovascular risk with low to moderate drinking. Then, with an increasing consumption, you can see that the advantage disappears, until the risk gets higher. The interesting part of our research is that, among the studies selected for this meta-analysis, there were 12 in which wine and beer consumption could be compared directly. Using these data we were able to observe that the risk curves for the two beverages are closely overlapping".
But beer as well as wine, drinkers, should be cautious before toasting too much at these results. "What we are talking about – says Augusto Di Castelnuovo, head of the Statistic Unit of Research Laboratories and a pioneer in alcohol epidemiological studies - is moderate and regular drinking. I think we will never stress enough this concept. Wine or beer are part of a lifestyle. One glass can pair with healthy foods, eaten at proper time, maybe together with family of friends. There is no place for binge drinking or any other form of heavy consumption.
"The data reported in our meta-analysis – Di Castelnuovo emphasizes- cannot be extrapolated to everybody. In young women still in their fertile age, as an example, alcohol can slightly raise the risk for some kind of cancer. This could counterbalance the positive effect on cardiovascular disease and reduce the overall benefit of alcoholic beverages on health".
In the similarity between wine and beer regarding positive effects on cardiovascular health there is a still unanswered question: the evidence we are observing derives from alcohol alone or from other substances contained in beverages? Wine and beer are different in composition, except for alcohol, so we could think this is the main player. But they both contain polyphenols, albeit different ones. Researchers at Fondazione "Giovanni Paolo II" underline how this is something to look at more closely in the future.
"A research like this - comments Giovanni de Gaetano, director of Research Laboratories at Fondazione "Giovanni Paolo II" – is part of a concept that our group strongly pursues: to look at people's real life. Health and disease are conditions deriving from our lifestyle. New therapies, new drugs, are extremely important. But a healthy life, with a strong attitude toward prevention, is the key element of the medicine in the years to come".
A study conducted by research laboratories at Fondazione 'Giovanni Paolo II' in Italy shows that beer, like wine, can reduce the risk of cardiovascular disease
Beer could stand up alongside wine regarding positive effects on cardiovascular health. This is the conclusion of a study conducted by Research Laboratories at the Fondazione di Ricerca e Cura "Giovanni Paolo II", in Campobasso, Italy. Both for wine and beer the key is moderate and regular drinking.
The research, published today on line by the European Journal of Epidemiology, using the statistic approach of meta-analysis, pooled different scientific studies conducted worldwide in previous years to achieve a general result. This way it has been possible to examine data concerning over 200,000 people, for whom alcohol drinking habits were associated with cardiovascular disease.
Results confirm what was already known about wine: a moderate consumption (approximately two glasses per day for men and one for women) can lower the risk of cardiovascular disease, up to 31% less when comparing to non drinkers. What this research adds are new data on beer. For the first time, in fact, evidence about dose-dependent effect is shown for this beverage. Maximum protection is observed, for a beer containing 5% of alcohol, with a consumption of slightly more than an English pint a day.
"In our research – explains Simona Costanzo, first author of the paper - we considered wine and beer separately: you first observe a reduction in cardiovascular risk with low to moderate drinking. Then, with an increasing consumption, you can see that the advantage disappears, until the risk gets higher. The interesting part of our research is that, among the studies selected for this meta-analysis, there were 12 in which wine and beer consumption could be compared directly. Using these data we were able to observe that the risk curves for the two beverages are closely overlapping".
But beer as well as wine, drinkers, should be cautious before toasting too much at these results. "What we are talking about – says Augusto Di Castelnuovo, head of the Statistic Unit of Research Laboratories and a pioneer in alcohol epidemiological studies - is moderate and regular drinking. I think we will never stress enough this concept. Wine or beer are part of a lifestyle. One glass can pair with healthy foods, eaten at proper time, maybe together with family of friends. There is no place for binge drinking or any other form of heavy consumption.
"The data reported in our meta-analysis – Di Castelnuovo emphasizes- cannot be extrapolated to everybody. In young women still in their fertile age, as an example, alcohol can slightly raise the risk for some kind of cancer. This could counterbalance the positive effect on cardiovascular disease and reduce the overall benefit of alcoholic beverages on health".
In the similarity between wine and beer regarding positive effects on cardiovascular health there is a still unanswered question: the evidence we are observing derives from alcohol alone or from other substances contained in beverages? Wine and beer are different in composition, except for alcohol, so we could think this is the main player. But they both contain polyphenols, albeit different ones. Researchers at Fondazione "Giovanni Paolo II" underline how this is something to look at more closely in the future.
"A research like this - comments Giovanni de Gaetano, director of Research Laboratories at Fondazione "Giovanni Paolo II" – is part of a concept that our group strongly pursues: to look at people's real life. Health and disease are conditions deriving from our lifestyle. New therapies, new drugs, are extremely important. But a healthy life, with a strong attitude toward prevention, is the key element of the medicine in the years to come".
Monday, November 14, 2011
Sugar-sweetened beverages may increase cardiovascular risk in women
Ω
Drinking two or more sugar-sweetened beverages a day may expand a woman's waistline and increase her risk of heart disease and diabetes, according to research presented at the American Heart Association's Scientific Sessions 2011.
In this study, researchers compared middle-aged and older women who drank two or more sugar-sweetened beverages a day, such as carbonated sodas or flavored waters with added sugar, to women who drank one or less daily. Women consuming two or more beverages per day were nearly four times as likely to develop high triglycerides, and were significantly more likely to increase their waist sizes and to develop impaired fasting glucose levels. The same associations were not observed in men.
"Women who drank more than two sugar-sweetened drinks a day had increasing waist sizes, but weren't necessarily gaining weight," said Christina Shay, Ph.D., lead author of the study and assistant professor at the University of Oklahoma Health Sciences Center in Oklahoma City. "These women also developed high triglycerides and women with normal blood glucose levels more frequently went from having a low risk to a high risk of developing diabetes over time."
The Multi-Ethnic Study of Atherosclerosis (MESA) included food frequency surveys in 4,166 African-American, Caucasian, Chinese-Americans and Hispanic adults 45 to 84 years old. At the beginning of the study the participants didn't have cardiovascular disease.
Researchers assessed risk factors in three follow-up exams spanning five years starting in 2002. Participants were monitored for weight gain, increases in waist circumference, low levels of high density lipoproteins (HDL "good" cholesterol), high levels of low density lipoproteins (LDL "bad" cholesterol), high triglycerides, impaired fasting glucose levels, and type 2 diabetes.
"Most people assume that individuals who consume a lot of sugar-sweetened drinks have an increase in obesity, which in turn, increases their risk for heart disease and diabetes," said Shay, formerly of Northwestern University's Department of Preventive Medicine in Chicago, where the study was conducted. "Although this does occur, this study showed that risk factors for heart disease and stroke developed even when the women didn't gain weight."
Women may have a greater chance for developing cardiovascular disease risk factors from sugar-sweetened drinks because they require fewer calories than men which makes each calorie count more towards cardiovascular risk in women, Shay said.
Researchers have yet to determine exactly how sugar-sweetened beverages influence cardiovascular risk factors such as high triglycerides in individuals who do not gain weight, Shay said, but further work is planned to try and figure that out.
Drinking two or more sugar-sweetened beverages a day may expand a woman's waistline and increase her risk of heart disease and diabetes, according to research presented at the American Heart Association's Scientific Sessions 2011.
In this study, researchers compared middle-aged and older women who drank two or more sugar-sweetened beverages a day, such as carbonated sodas or flavored waters with added sugar, to women who drank one or less daily. Women consuming two or more beverages per day were nearly four times as likely to develop high triglycerides, and were significantly more likely to increase their waist sizes and to develop impaired fasting glucose levels. The same associations were not observed in men.
"Women who drank more than two sugar-sweetened drinks a day had increasing waist sizes, but weren't necessarily gaining weight," said Christina Shay, Ph.D., lead author of the study and assistant professor at the University of Oklahoma Health Sciences Center in Oklahoma City. "These women also developed high triglycerides and women with normal blood glucose levels more frequently went from having a low risk to a high risk of developing diabetes over time."
The Multi-Ethnic Study of Atherosclerosis (MESA) included food frequency surveys in 4,166 African-American, Caucasian, Chinese-Americans and Hispanic adults 45 to 84 years old. At the beginning of the study the participants didn't have cardiovascular disease.
Researchers assessed risk factors in three follow-up exams spanning five years starting in 2002. Participants were monitored for weight gain, increases in waist circumference, low levels of high density lipoproteins (HDL "good" cholesterol), high levels of low density lipoproteins (LDL "bad" cholesterol), high triglycerides, impaired fasting glucose levels, and type 2 diabetes.
"Most people assume that individuals who consume a lot of sugar-sweetened drinks have an increase in obesity, which in turn, increases their risk for heart disease and diabetes," said Shay, formerly of Northwestern University's Department of Preventive Medicine in Chicago, where the study was conducted. "Although this does occur, this study showed that risk factors for heart disease and stroke developed even when the women didn't gain weight."
Women may have a greater chance for developing cardiovascular disease risk factors from sugar-sweetened drinks because they require fewer calories than men which makes each calorie count more towards cardiovascular risk in women, Shay said.
Researchers have yet to determine exactly how sugar-sweetened beverages influence cardiovascular risk factors such as high triglycerides in individuals who do not gain weight, Shay said, but further work is planned to try and figure that out.
Aerobic Fitness May Reduce Brain Aging
Ω
New findings suggest exercise may help maintain cognitive abilities of seniors
Physically fit seniors show fewer age-related changes in their brains, according to new research presented at Neuroscience 2011, the annual meeting of the Society for Neuroscience and the world’s largest source of emerging news about brain science and health. The findings underscore the importance of exercise for maintaining brain health throughout life.
"Our findings suggest that a high level of aerobic fitness may help diminish the changes in brain structure that occur as we get older," said senior author Gene Alexander, PhD, of the University of Arizona.
As people age, some regions of the brain — including those responsible for attention and memory functions — begin to lose volume or shrink. To see how physical fitness affects brain aging and age-associated declines in cognition, Alexander and colleagues scanned the brains of 58 men and 65 women (ages 50 to 89 years) and evaluated their performance walking on an inclined treadmill.
The more physically fit a participant was, the less age-related brain changes they showed. In particular, exercise endurance and breathing efficiency offered the best combination of fitness measures in predicting patterns of brain aging. Individuals with higher levels of aerobic fitness also outperformed their less physically fit counterparts on tests measuring memory, executive function, and information processing.
"Identifying the fitness indices that are the best predictors of brain aging and cognitive performance may help improve exercise-based interventions — ones that could delay or prevent changes in the brain that lead to age-related cognitive decline," Alexander said.
Ω
New findings suggest exercise may help maintain cognitive abilities of seniors
Physically fit seniors show fewer age-related changes in their brains, according to new research presented at Neuroscience 2011, the annual meeting of the Society for Neuroscience and the world’s largest source of emerging news about brain science and health. The findings underscore the importance of exercise for maintaining brain health throughout life.
"Our findings suggest that a high level of aerobic fitness may help diminish the changes in brain structure that occur as we get older," said senior author Gene Alexander, PhD, of the University of Arizona.
As people age, some regions of the brain — including those responsible for attention and memory functions — begin to lose volume or shrink. To see how physical fitness affects brain aging and age-associated declines in cognition, Alexander and colleagues scanned the brains of 58 men and 65 women (ages 50 to 89 years) and evaluated their performance walking on an inclined treadmill.
The more physically fit a participant was, the less age-related brain changes they showed. In particular, exercise endurance and breathing efficiency offered the best combination of fitness measures in predicting patterns of brain aging. Individuals with higher levels of aerobic fitness also outperformed their less physically fit counterparts on tests measuring memory, executive function, and information processing.
"Identifying the fitness indices that are the best predictors of brain aging and cognitive performance may help improve exercise-based interventions — ones that could delay or prevent changes in the brain that lead to age-related cognitive decline," Alexander said.
Ω
Adolescent alcohol consumption and breast cancer
Ω
Alcohol consumption by adolescents may increase breast cancer risk in those with a family history of the disease
Breast cancer patients often wonder what their daughters might do to reduce their risk of also developing cancer. Are there dietary intakes or behaviors that can be modified by their daughters to lower their own chances of getting the disease? A new study published early online in CANCER, a peer-reviewed journal of the American Cancer Society, sought information relevant to this question.
Dr. Catherine Berkey, a biostatistician at Brigham & Women's Hospital and Harvard Medical School in Boston, led a team that investigated childhood and adolescent risk factors for benign breast disease among girls with a family history of breast cancer. Benign breast disease, a large class of breast ailments that can cause breast lumps or breast pain, is a known risk factor for breast cancer. The authors found that among adolescent girls with a family history of breast cancer (or maternal benign breast disease), there was a significant association between amount of alcohol consumed and further increased risk of getting benign breast disease as young women.
The investigators analyzed information from the Growing Up Today Study (GUTS, founded by co-author Dr. Graham Colditz), which includes females who were aged nine to 15 years old in 1996 and who completed annual questionnaires from 1996 to 2001, then again in 2003, 2005, and 2007. Participants provided information regarding alcohol consumption, age at first menstrual period, height, and body mass index.
In the final two surveys, the participants (who were aged 18 to 27 years at the time) reported whether they had ever been diagnosed with benign breast disease. A total of 67 reported receiving this diagnosis (confirmed by breast biopsy), while another 6,741 reported they had never been diagnosed with the disease. Also, participants' mothers reported their own cases of benign breast disease and breast cancer, as well as breast cancer in their sisters and mothers (maternal aunts and maternal grandmothers of the participants).
Young women whose mothers or aunts had breast cancer were more than twice as likely to be diagnosed with benign breast disease compared to young women with no family history. Young women whose mothers had benign breast disease also saw their own risk (for benign breast disease) nearly double. More importantly, among adolescent girls having a mother, aunt, or grandmother with breast cancer, the more alcohol the girls consumed, the more likely they were to develop benign breast disease as young women. The same held true for girls whose mothers had benign breast disease. These findings are consistent with previous studies (on older women) showing that drinking by adult women increases their risk of breast cancer.
"Our study suggests that adolescent females already at higher risk for breast cancer, in light of their family history, should be aware that avoiding alcohol may reduce their risk for benign breast disease as young women, which might be accompanied by reduced breast cancer risk later in life" said Dr. Berkey.
Furthermore, girls with a family history who had the most rapid height growth spurt were at increased risk, whereas in girls with no family history, height and body shape impacted their chances of developing benign breast disease. These findings suggest that risk factors for breast cancer may differ between women with a family history of breast cancer and women without a family history.
Alcohol consumption by adolescents may increase breast cancer risk in those with a family history of the disease
Breast cancer patients often wonder what their daughters might do to reduce their risk of also developing cancer. Are there dietary intakes or behaviors that can be modified by their daughters to lower their own chances of getting the disease? A new study published early online in CANCER, a peer-reviewed journal of the American Cancer Society, sought information relevant to this question.
Dr. Catherine Berkey, a biostatistician at Brigham & Women's Hospital and Harvard Medical School in Boston, led a team that investigated childhood and adolescent risk factors for benign breast disease among girls with a family history of breast cancer. Benign breast disease, a large class of breast ailments that can cause breast lumps or breast pain, is a known risk factor for breast cancer. The authors found that among adolescent girls with a family history of breast cancer (or maternal benign breast disease), there was a significant association between amount of alcohol consumed and further increased risk of getting benign breast disease as young women.
The investigators analyzed information from the Growing Up Today Study (GUTS, founded by co-author Dr. Graham Colditz), which includes females who were aged nine to 15 years old in 1996 and who completed annual questionnaires from 1996 to 2001, then again in 2003, 2005, and 2007. Participants provided information regarding alcohol consumption, age at first menstrual period, height, and body mass index.
In the final two surveys, the participants (who were aged 18 to 27 years at the time) reported whether they had ever been diagnosed with benign breast disease. A total of 67 reported receiving this diagnosis (confirmed by breast biopsy), while another 6,741 reported they had never been diagnosed with the disease. Also, participants' mothers reported their own cases of benign breast disease and breast cancer, as well as breast cancer in their sisters and mothers (maternal aunts and maternal grandmothers of the participants).
Young women whose mothers or aunts had breast cancer were more than twice as likely to be diagnosed with benign breast disease compared to young women with no family history. Young women whose mothers had benign breast disease also saw their own risk (for benign breast disease) nearly double. More importantly, among adolescent girls having a mother, aunt, or grandmother with breast cancer, the more alcohol the girls consumed, the more likely they were to develop benign breast disease as young women. The same held true for girls whose mothers had benign breast disease. These findings are consistent with previous studies (on older women) showing that drinking by adult women increases their risk of breast cancer.
"Our study suggests that adolescent females already at higher risk for breast cancer, in light of their family history, should be aware that avoiding alcohol may reduce their risk for benign breast disease as young women, which might be accompanied by reduced breast cancer risk later in life" said Dr. Berkey.
Furthermore, girls with a family history who had the most rapid height growth spurt were at increased risk, whereas in girls with no family history, height and body shape impacted their chances of developing benign breast disease. These findings suggest that risk factors for breast cancer may differ between women with a family history of breast cancer and women without a family history.
Saturday, November 12, 2011
Jon's Health Tips - Latest Health Research
Recent reports discuss the benefits of:
Pomegranate juice (lowers cholesterol and blood pressure}
Fish (reduces the risk of diabetes)
Omega 3 (Reduces Anxiety And Inflammation)
Slow eating (reduces food intake)
Vitamin D (Light-skinned people who avoid the sun are twice as likely to suffer from vitamin D deficiency as those who do not)
More on Vitamin D (fights chronic digestive conditions)
Vegetarian diet, physical activity (protect against diabetes)
Physical activity (lower risk of depression in old age)
Nuts (decreases feelings of hunger, makes people feel happier and improves heart health)
Mediterranean diet and exercise (can reduce sleep apnea symptoms)
Resveratrol (metabolisms change for the better. In fact, the effects appear to be as as severe calorie restriction)
Probiotics (effective in combating antibiotic-associated diarrhea)
Fiber (lower risk of heart disease and type-2 diabetes)
Previous Reports
October 29
October 7
September 19
August 26
August 11
July 22
June 25
June 4
May 21
May 7
April 13
March 29
March 2
Pomegranate juice (lowers cholesterol and blood pressure}
Fish (reduces the risk of diabetes)
Omega 3 (Reduces Anxiety And Inflammation)
Slow eating (reduces food intake)
Vitamin D (Light-skinned people who avoid the sun are twice as likely to suffer from vitamin D deficiency as those who do not)
More on Vitamin D (fights chronic digestive conditions)
Vegetarian diet, physical activity (protect against diabetes)
Physical activity (lower risk of depression in old age)
Nuts (decreases feelings of hunger, makes people feel happier and improves heart health)
Mediterranean diet and exercise (can reduce sleep apnea symptoms)
Resveratrol (metabolisms change for the better. In fact, the effects appear to be as as severe calorie restriction)
Probiotics (effective in combating antibiotic-associated diarrhea)
Fiber (lower risk of heart disease and type-2 diabetes)
Previous Reports
October 29
October 7
September 19
August 26
August 11
July 22
June 25
June 4
May 21
May 7
April 13
March 29
March 2
Health Effects of Green and White Tea
Ω
In doing research on the above, I came across this Wikipedia article.
I immediately
1. Wrote this note
2. Went off to brew more white tea, which I will drink with some orange juice.
Read the article!
In doing research on the above, I came across this Wikipedia article.
I immediately
1. Wrote this note
2. Went off to brew more white tea, which I will drink with some orange juice.
Read the article!
Friday, November 11, 2011
Pomegranate juice lowers kidney disease patients' cholesterol, blood pressure, and the need for blood pressure medications
Ω
Lilach Shema, PhD (Western Galilee Medical Center in Israel) and colleagues investigated the long-term effects of drinking pomegranate juice on heart disease risk factors -- such as high cholesterol and blood pressure -- in kidney disease patients. Pomegranate juice is rich in antioxidants and has been touted as having a variety of health benefits.
The researchers randomized 101 dialysis patients to receive about three-and-a-half ounces of pomegranate juice or placebo, three times a week. After one year, the number of blood pressure drugs patients took decreased in 22% of patients drinking pomegranate juice compared to 7.7% in the placebo group, while an increase was documented in 12.2% of patients drinking pomegranate juice compared to 34.6% in the placebo group. Patients who drank pomegranate juice also had healthier blood pressure and cholesterol levels and less plaque build-up in their arteries. These results suggest that drinking pomegranate juice might decrease the high rates of illness and death among kidney disease patients.
Lilach Shema, PhD (Western Galilee Medical Center in Israel) and colleagues investigated the long-term effects of drinking pomegranate juice on heart disease risk factors -- such as high cholesterol and blood pressure -- in kidney disease patients. Pomegranate juice is rich in antioxidants and has been touted as having a variety of health benefits.
The researchers randomized 101 dialysis patients to receive about three-and-a-half ounces of pomegranate juice or placebo, three times a week. After one year, the number of blood pressure drugs patients took decreased in 22% of patients drinking pomegranate juice compared to 7.7% in the placebo group, while an increase was documented in 12.2% of patients drinking pomegranate juice compared to 34.6% in the placebo group. Patients who drank pomegranate juice also had healthier blood pressure and cholesterol levels and less plaque build-up in their arteries. These results suggest that drinking pomegranate juice might decrease the high rates of illness and death among kidney disease patients.
Eating fish can reduce the risk of diabetes
Ω
A study analyzes the dietary patterns of the adult Spanish population with high cardiovascular risk. The results reveal a high consumption of both red meat and fish. However, whilst eating lots of cured meats is associated with greater weight gain and a higher obesity rate, the consumption of fish is linked to lower glucose concentrations and a smaller risk of developing diabetes.
A study analyzes the dietary patterns of the adult Spanish population with high cardiovascular risk. The results reveal a high consumption of both red meat and fish. However, whilst eating lots of cured meats is associated with greater weight gain and a higher obesity rate, the consumption of fish is linked to lower glucose concentrations and a smaller risk of developing diabetes.
More Fiber, but Not Necessarily Less Fat, Good for Teen Diets
Ω
A diet high in fiber -- but not necessarily one low in saturated fat or cholesterol -- is tied to a lower risk of heart disease and type-2 diabetes in teenagers, according to new findings from Michigan State University.
A study led by Joseph Carlson of MSU's Division of Sports and Cardiovascular Nutrition suggests to reduce metabolic syndrome -- a collection of risk factors including high blood pressure and a large waistline -- it is more important to emphasize diets including fiber-rich, nutrient-dense, plant-based foods than focus on restricting foods high in cholesterol or saturated fat.
The research is published in Journal of the American Dietetic Association.
"What we found is that as fiber intake increases, the risk for metabolic syndrome decreases," said Carlson, a registered dietitian and associate professor at MSU. "High-fiber, nutrient-dense foods are packed with heart healthy vitamins, minerals and chemicals that can positively affect many cardiovascular risk factors.
"It may be better to focus on including these foods than to focus, as is commonly done, on excluding foods high in saturated fat."
That does not mean, however, that teens should have carte blanche in eating foods high in saturated fat and cholesterol, Carlson said.
"It is well established that saturated fat can raise bad cholesterol," he said. "What this data suggest is the importance of including foods high in dietary fiber."
With the high availability of processed foods today, Carlson said, it is possible for teens to eat a diet that is low in saturated fat and cholesterol but that also is low in fiber and nutrient-rich, plant-based foods. Recent national data indicates up to 30 percent of teens' dietary intake comes from beverages and sugar-rich snacks.
Due to low intakes of fruits, vegetables, whole grains and beans, the total dietary fiber intake in teens is about 13 grams per day, well below the recommendation of 26 grams and 38 grams for female and male adolescents, respectively.
In addition, obesity and other key risk factors associated with metabolic syndrome are on the rise in youth; more than 70 percent of teens in the study had at least one of the five risk factors used to assess metabolic syndrome: high blood pressure, high levels of sugar and fat in the blood, low levels of good cholesterol and a large waistline (a person having three or more of the factors are classified as having the syndrome).
"One of the takeaways is that our study reinforced the current dietary recommendations for dietary fiber intake by including a variety of plant-based foods," Carlson said. "A strategy of emphasizing fiber-rich foods may improve adherence to dietary recommendations."
The next step, he said, is to figure out the best methods to boost dietary fiber intakes to levels that will improve or sustain a desirable cardiovascular risk factor status. For example, if a person daily has three servings of fruit and vegetables (12 grams of fiber), one serving of beans (seven grams), and three servings of whole grain, they will be at about 30 grams of dietary fiber.
"The trick is getting people in the groove finding the foods that they both enjoy and are convenient," Carlson said.
As part of the cross-sectional study, Carlson and his team focused on data collected as part of the National Health and Nutrition Examination Survey done from 1999-2002. They analyzed the diets of more than 2,100 boys and girls ages 12 to 19, looking at whether the teens had three or more conditions that make up metabolic syndrome.
The study found there was a three-fold increase in the number of children that had metabolic syndrome when the group of children receiving the least fiber was compared with the group receiving the most. There was not a significant relationship with either saturated fat or cholesterol intake.
A diet high in fiber -- but not necessarily one low in saturated fat or cholesterol -- is tied to a lower risk of heart disease and type-2 diabetes in teenagers, according to new findings from Michigan State University.
A study led by Joseph Carlson of MSU's Division of Sports and Cardiovascular Nutrition suggests to reduce metabolic syndrome -- a collection of risk factors including high blood pressure and a large waistline -- it is more important to emphasize diets including fiber-rich, nutrient-dense, plant-based foods than focus on restricting foods high in cholesterol or saturated fat.
The research is published in Journal of the American Dietetic Association.
"What we found is that as fiber intake increases, the risk for metabolic syndrome decreases," said Carlson, a registered dietitian and associate professor at MSU. "High-fiber, nutrient-dense foods are packed with heart healthy vitamins, minerals and chemicals that can positively affect many cardiovascular risk factors.
"It may be better to focus on including these foods than to focus, as is commonly done, on excluding foods high in saturated fat."
That does not mean, however, that teens should have carte blanche in eating foods high in saturated fat and cholesterol, Carlson said.
"It is well established that saturated fat can raise bad cholesterol," he said. "What this data suggest is the importance of including foods high in dietary fiber."
With the high availability of processed foods today, Carlson said, it is possible for teens to eat a diet that is low in saturated fat and cholesterol but that also is low in fiber and nutrient-rich, plant-based foods. Recent national data indicates up to 30 percent of teens' dietary intake comes from beverages and sugar-rich snacks.
Due to low intakes of fruits, vegetables, whole grains and beans, the total dietary fiber intake in teens is about 13 grams per day, well below the recommendation of 26 grams and 38 grams for female and male adolescents, respectively.
In addition, obesity and other key risk factors associated with metabolic syndrome are on the rise in youth; more than 70 percent of teens in the study had at least one of the five risk factors used to assess metabolic syndrome: high blood pressure, high levels of sugar and fat in the blood, low levels of good cholesterol and a large waistline (a person having three or more of the factors are classified as having the syndrome).
"One of the takeaways is that our study reinforced the current dietary recommendations for dietary fiber intake by including a variety of plant-based foods," Carlson said. "A strategy of emphasizing fiber-rich foods may improve adherence to dietary recommendations."
The next step, he said, is to figure out the best methods to boost dietary fiber intakes to levels that will improve or sustain a desirable cardiovascular risk factor status. For example, if a person daily has three servings of fruit and vegetables (12 grams of fiber), one serving of beans (seven grams), and three servings of whole grain, they will be at about 30 grams of dietary fiber.
"The trick is getting people in the groove finding the foods that they both enjoy and are convenient," Carlson said.
As part of the cross-sectional study, Carlson and his team focused on data collected as part of the National Health and Nutrition Examination Survey done from 1999-2002. They analyzed the diets of more than 2,100 boys and girls ages 12 to 19, looking at whether the teens had three or more conditions that make up metabolic syndrome.
The study found there was a three-fold increase in the number of children that had metabolic syndrome when the group of children receiving the least fiber was compared with the group receiving the most. There was not a significant relationship with either saturated fat or cholesterol intake.
Thursday, November 10, 2011
Reduction in risk of coronary heart disease from alcohol consumption
Ω
In a prospective, observational study of approximately 150,000 Norwegians, the investigators found that alcohol consumption was associated with a large decrease in the risk of death from coronary artery disease. For men, the fully adjusted hazard ratio for cardiac death was 0.52 (in other words, only about 1/2 the risk of dying) when comparing subjects reporting more than one drink/week in comparison with those reporting never or rarely drinking; for women, it was 0.62 (only about 3/5 the risk of dying). There was little change in the hazard ratio when HDL-cholesterol (HDL) was added to the model, suggesting that very little of the lower risk of heart disease was due to an increase in HDL from alcohol consumption.
Forum members considered this a well-done analysis. They were surprised at the very low amounts of alcohol intake reported by the subjects, with only 16% of males and about 8% of females reporting more than one drink/week. It is possible that the low levels of drinking, or perhaps over-adjustment in the multivariable analysis, led to the lack of effect of HDL. Most other studies have shown a much larger proportion of the effect of alcohol on heart disease risk to be associated with an increase in HDL.
In a prospective, observational study of approximately 150,000 Norwegians, the investigators found that alcohol consumption was associated with a large decrease in the risk of death from coronary artery disease. For men, the fully adjusted hazard ratio for cardiac death was 0.52 (in other words, only about 1/2 the risk of dying) when comparing subjects reporting more than one drink/week in comparison with those reporting never or rarely drinking; for women, it was 0.62 (only about 3/5 the risk of dying). There was little change in the hazard ratio when HDL-cholesterol (HDL) was added to the model, suggesting that very little of the lower risk of heart disease was due to an increase in HDL from alcohol consumption.
Forum members considered this a well-done analysis. They were surprised at the very low amounts of alcohol intake reported by the subjects, with only 16% of males and about 8% of females reporting more than one drink/week. It is possible that the low levels of drinking, or perhaps over-adjustment in the multivariable analysis, led to the lack of effect of HDL. Most other studies have shown a much larger proportion of the effect of alcohol on heart disease risk to be associated with an increase in HDL.
Wednesday, November 9, 2011
OMEGA-3 Reduces Anxiety And Inflammation
Ω
A recent study gauging the impact of consuming more fish oil showed a marked reduction both in inflammation and, surprisingly, in anxiety among a cohort of healthy young people.
The research, supported by the Ohio State University Center for Clinical and Translational Science (CCTS), was conducted by a team of scientists that has spent more than three decades investigating links between psychological stress and immunity.
“The findings suggest that if young people can get improvements from dietary supplements, then the elderly and people at high risk for certain diseases might benefit even more,” said Janice Kiecolt-Glaser, professor of psychiatry and author of the study, which was published this month in the journal Brain, Behavior and Immunity.
“The more we understand about the complex interplay between inflammation and immunity, the closer we’ll get to figuring out which lifestyle choices and changes have the biggest impact on long term health.”
Omega-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have long been considered as positive additives to the diet.
Earlier research suggested that the compounds might play a role in reducing the level of cytokines in the body, compounds that promote inflammation, and perhaps even reduce depression.
Psychological stress has repeatedly been shown to increase cytokine production so the researchers wondered if increasing omega-3 might mitigate that process, reducing inflammation.
To test their theory, they turned to a familiar group of research subjects – medical students. Some of the earliest work these scientists did showed that stress from important medical school tests lowered students’ immune status.
“We hypothesized that giving some students omega-3 supplements would decrease their production of proinflammatory cytokines, compared to other students who only received a placebo,” explained Kiecolt-Glaser.
“We thought the omega-3 would reduce the stress-induced increase in cytokines that normally arose from nervousness over the tests.”
The team assembled a field of 68 first- and second-year medical students who volunteered for the clinical trial. Half the students received omega-3 supplements while the other half were given placebo pills. The students were randomly divided into six groups, all of which were interviewed six times during the study. At each visit, blood samples were drawn from the students who also completed a battery of psychological surveys intended to gauge their levels of stress, anxiety or depression. The students also completed questionnaires about their diets during the previous weeks
.
“The omega-3 supplement the students received was probably about four or five times the amount of fish oil you’d get from a daily serving of salmon,” explained Martha Belury, professor of human nutrition and co-author in the study.
Part of the study, however, didn’t go according to plans.
Changes in the medical curriculum and the distribution of major tests throughout the year, rather than during a tense three-day period as was done in the past, removed much of the stress that medical students had shown in past studies.
“These students were not anxious. They weren’t really stressed. They were actually sleeping well throughout this period, so we didn’t get the stress effect we had expected,” Kiecolt-Glaser said.
But the psychological surveys clearly showed an important change in anxiety among the students: Those receiving the omega-3 showed a 20 percent reduction in anxiety compared to the placebo group. An analysis of the of the blood samples from the medical students showed similar important results.
“We took measurements of the cytokines in the blood serum, as well as measured the productivity of cells that produced two important cytokines, interleukin-6 (IL-6) and tumor necrosis factor alpha (TNFα),” said Ron Glaser, professor of molecular virology, immunology & medical genetics and director of the Institute for Behavioral Medicine Research.
“We saw a 14 percent reduction in the amounts of IL-6 among the students receiving the omega-3.” Since the cytokines foster inflammation, “anything we can do to reduce cytokines is a big plus in dealing with the overall health of people at risk for many diseases,” he said.
Inflammation is a natural immune response that helps the body heal, but it also can play a harmful role in a host of diseases ranging from arthritis to heart disease to cancer.
Even though the study showed omega-3 supplements can reduce both anxiety and inflammation – and some of the researchers said that they take omega-3 supplements – the researchers aren’t ready to recommend that the public start taking them daily.
"It may be too early to recommend a broad use of omega-3 supplements, especially considering the cost and the limited supplies of fish needed to supply the oil,” Belury said. “People should just consider increasing their omega-3 through their diet.”
Also working on the research with Kiecolt-Glaser, Glaser and Belury were William Malarkey, professor emeritus of internal medicine, and Rebecca Andridge, an assistant professor of public health.
A recent study gauging the impact of consuming more fish oil showed a marked reduction both in inflammation and, surprisingly, in anxiety among a cohort of healthy young people.
The research, supported by the Ohio State University Center for Clinical and Translational Science (CCTS), was conducted by a team of scientists that has spent more than three decades investigating links between psychological stress and immunity.
“The findings suggest that if young people can get improvements from dietary supplements, then the elderly and people at high risk for certain diseases might benefit even more,” said Janice Kiecolt-Glaser, professor of psychiatry and author of the study, which was published this month in the journal Brain, Behavior and Immunity.
“The more we understand about the complex interplay between inflammation and immunity, the closer we’ll get to figuring out which lifestyle choices and changes have the biggest impact on long term health.”
Omega-3 polyunsaturated fatty acids, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have long been considered as positive additives to the diet.
Earlier research suggested that the compounds might play a role in reducing the level of cytokines in the body, compounds that promote inflammation, and perhaps even reduce depression.
Psychological stress has repeatedly been shown to increase cytokine production so the researchers wondered if increasing omega-3 might mitigate that process, reducing inflammation.
To test their theory, they turned to a familiar group of research subjects – medical students. Some of the earliest work these scientists did showed that stress from important medical school tests lowered students’ immune status.
“We hypothesized that giving some students omega-3 supplements would decrease their production of proinflammatory cytokines, compared to other students who only received a placebo,” explained Kiecolt-Glaser.
“We thought the omega-3 would reduce the stress-induced increase in cytokines that normally arose from nervousness over the tests.”
The team assembled a field of 68 first- and second-year medical students who volunteered for the clinical trial. Half the students received omega-3 supplements while the other half were given placebo pills. The students were randomly divided into six groups, all of which were interviewed six times during the study. At each visit, blood samples were drawn from the students who also completed a battery of psychological surveys intended to gauge their levels of stress, anxiety or depression. The students also completed questionnaires about their diets during the previous weeks
.
“The omega-3 supplement the students received was probably about four or five times the amount of fish oil you’d get from a daily serving of salmon,” explained Martha Belury, professor of human nutrition and co-author in the study.
Part of the study, however, didn’t go according to plans.
Changes in the medical curriculum and the distribution of major tests throughout the year, rather than during a tense three-day period as was done in the past, removed much of the stress that medical students had shown in past studies.
“These students were not anxious. They weren’t really stressed. They were actually sleeping well throughout this period, so we didn’t get the stress effect we had expected,” Kiecolt-Glaser said.
But the psychological surveys clearly showed an important change in anxiety among the students: Those receiving the omega-3 showed a 20 percent reduction in anxiety compared to the placebo group. An analysis of the of the blood samples from the medical students showed similar important results.
“We took measurements of the cytokines in the blood serum, as well as measured the productivity of cells that produced two important cytokines, interleukin-6 (IL-6) and tumor necrosis factor alpha (TNFα),” said Ron Glaser, professor of molecular virology, immunology & medical genetics and director of the Institute for Behavioral Medicine Research.
“We saw a 14 percent reduction in the amounts of IL-6 among the students receiving the omega-3.” Since the cytokines foster inflammation, “anything we can do to reduce cytokines is a big plus in dealing with the overall health of people at risk for many diseases,” he said.
Inflammation is a natural immune response that helps the body heal, but it also can play a harmful role in a host of diseases ranging from arthritis to heart disease to cancer.
Even though the study showed omega-3 supplements can reduce both anxiety and inflammation – and some of the researchers said that they take omega-3 supplements – the researchers aren’t ready to recommend that the public start taking them daily.
"It may be too early to recommend a broad use of omega-3 supplements, especially considering the cost and the limited supplies of fish needed to supply the oil,” Belury said. “People should just consider increasing their omega-3 through their diet.”
Also working on the research with Kiecolt-Glaser, Glaser and Belury were William Malarkey, professor emeritus of internal medicine, and Rebecca Andridge, an assistant professor of public health.
Slow eating reduces food intake
Ω
Two new studies by researchers at the University of Rhode Island are providing additional insights into the role that eating rate plays in the amount of food one consumes. The studies found that men eat significantly faster than women, heavier people eat faster than slimmer people, and refined grains are consumed faster than whole grains, among other findings.
Kathleen Melanson, URI associate professor of nutrition, along with graduate students Emily Ponte and Amanda Petty, presented their research at the annual meeting of The Obesity Society in Orlando this month.
In one laboratory study, which validated that self-reported eating rates reflect an individual's actual eating rate, Melanson and her lab team found that fast eaters consumed about 3.1 ounces of food per minute, medium-speed eaters consumed 2.5 ounces per minute, and slow eaters consumed 2 ounces per minute. This work is the first to validate self-reported eating rates that have been used in large population studies, which have shown relationships between eating rate and body weight.
The researchers also found what Melanson described as "very strong gender differences" in eating rates. At lunch, the men consumed about 80 calories per minute while the women consumed 52 calories per minute.
"The men who reported eating slowly ate at about the same rate as the women who reported eating quickly," said Melanson, director of the URI Energy Balance Laboratory.
The second study, which examined the characteristics associated with eating rates, found a close association between eating rate and body mass index (BMI), with those individuals with a high BMI typically eating considerably faster than those with a low BMI.
"One theory we are pursuing is that fast eating may be related to greater energy needs, since men and heavier people have higher energy needs," said Melanson.
In what Melanson called her favorite result, the study also found that the test subjects consumed a meal of whole grains – whole grain cereal and whole wheat toast – significantly slower than when eating a similar meal of refined grains.
"Whole grains are more fibrous, so you have to chew them more, which takes more time," she said.
According to Melanson, these studies have raised a number of additional questions that she intends to pursue with future research.
"When you talk about eating rate, you have to talk about eating techniques," she explained. "It's not just about how long it takes you to eat, but how you eat."
She plans to study specific slow-eating techniques to see how they may affect appetite and weight loss. She will also examine other factors that might influence eating rate in daily life.
"We also want to recruit fast-paced eaters with a high BMI, teach them how to eat slowly, and see what role that might play in weight management," Melanson said.
While the link between eating rate and obesity is still being studied, Melanson said that her research has demonstrated that eating slowly results in significantly fewer average calories being consumed.
"It takes time for your body to process fullness signals," she concluded, "so slower eating may allow time for fullness to register in the brain before you've eaten too much."
The latest research follows up on a landmark 2007 study conducted by Melanson that was the first to confirm the popular dietary belief that eating slowly reduces food intake. That study found that women who were told to eat quickly consumed 646 calories in nine minutes, but the same women consumed just 579 calories in 29 minutes when encouraged to pause between bites and chew each mouthful 15 to 20 times before swallowing.
Two new studies by researchers at the University of Rhode Island are providing additional insights into the role that eating rate plays in the amount of food one consumes. The studies found that men eat significantly faster than women, heavier people eat faster than slimmer people, and refined grains are consumed faster than whole grains, among other findings.
Kathleen Melanson, URI associate professor of nutrition, along with graduate students Emily Ponte and Amanda Petty, presented their research at the annual meeting of The Obesity Society in Orlando this month.
In one laboratory study, which validated that self-reported eating rates reflect an individual's actual eating rate, Melanson and her lab team found that fast eaters consumed about 3.1 ounces of food per minute, medium-speed eaters consumed 2.5 ounces per minute, and slow eaters consumed 2 ounces per minute. This work is the first to validate self-reported eating rates that have been used in large population studies, which have shown relationships between eating rate and body weight.
The researchers also found what Melanson described as "very strong gender differences" in eating rates. At lunch, the men consumed about 80 calories per minute while the women consumed 52 calories per minute.
"The men who reported eating slowly ate at about the same rate as the women who reported eating quickly," said Melanson, director of the URI Energy Balance Laboratory.
The second study, which examined the characteristics associated with eating rates, found a close association between eating rate and body mass index (BMI), with those individuals with a high BMI typically eating considerably faster than those with a low BMI.
"One theory we are pursuing is that fast eating may be related to greater energy needs, since men and heavier people have higher energy needs," said Melanson.
In what Melanson called her favorite result, the study also found that the test subjects consumed a meal of whole grains – whole grain cereal and whole wheat toast – significantly slower than when eating a similar meal of refined grains.
"Whole grains are more fibrous, so you have to chew them more, which takes more time," she said.
According to Melanson, these studies have raised a number of additional questions that she intends to pursue with future research.
"When you talk about eating rate, you have to talk about eating techniques," she explained. "It's not just about how long it takes you to eat, but how you eat."
She plans to study specific slow-eating techniques to see how they may affect appetite and weight loss. She will also examine other factors that might influence eating rate in daily life.
"We also want to recruit fast-paced eaters with a high BMI, teach them how to eat slowly, and see what role that might play in weight management," Melanson said.
While the link between eating rate and obesity is still being studied, Melanson said that her research has demonstrated that eating slowly results in significantly fewer average calories being consumed.
"It takes time for your body to process fullness signals," she concluded, "so slower eating may allow time for fullness to register in the brain before you've eaten too much."
The latest research follows up on a landmark 2007 study conducted by Melanson that was the first to confirm the popular dietary belief that eating slowly reduces food intake. That study found that women who were told to eat quickly consumed 646 calories in nine minutes, but the same women consumed just 579 calories in 29 minutes when encouraged to pause between bites and chew each mouthful 15 to 20 times before swallowing.
Monday, November 7, 2011
Alcohol Pluses and Minuses
Reports in the last two weeks have focused on some negative aspects of alcohol consumption (click on links in each paragraph for more details.)
According to one report: "Just one drink per day for women -- two for men -- could lead to small intestinal bacterial overgrowth (SIBO) and subsequently cause gastrointestinal symptoms like bloating, gas, abdominal pain, constipation and diarrhea."
Another report: Consumption of 3 to 6 alcoholic drinks per week is associated with a small increase in the risk of breast cancer...However, an individual will need to weigh the modest risks of light to moderate alcohol use on breast cancer development against the beneficial effects on cardiovascular disease to make the best personal choice regarding alcohol consumption."
I thought it might be useful in light of those recent reports to review some of the reported benefits of alcohol consumption:
Most recent reports:
Women who drink 15 grams or less of alcohol a day (the equivalent of one drink of any alcoholic beverage) at midlife may be healthier when older than women who do not drink at all, who consume more than two drinks a day, or who consume four drinks or more at the one time, according to a new study.
Among 13,894 women in the Nurses' Health Study, investigators prospectively examined alcohol use assessed at midlife in relation to "successful ageing," which was defined as survival to age 70 years, not having a major chronic disease (such as coronary disease, cancer, stroke, diabetes), and having no major cognitive impairment, physical impairment, or mental health problems. Only 11% of the women met these criteria.
The results indicate that moderate drinkers, especially those consuming wine and drinking regularly, were more likely to exhibit successful ageing. For average amount consumed, the largest benefit (an increase of 28%) was among women who reported 15.1 – 30 g of alcohol per day (an average of just over 1 to 2 ½ drinks per day), when compared with non-drinkers. The frequency of drinking was especially important: in comparison with nondrinkers, women who drank only on 1 to 2 days per week had little increase in their risk of successful ageing, but those drinking on at least 5 days per week had almost a 50% greater chance of successful ageing.
Older reports:
Men who drink alcohol every day have a lower risk of heart disease than those who drink less frequently, suggests research in the British Medical Journal.
A new study provides further evidence that alcohol, when consumed in moderation, reduces the risk of death, and not just that due to cardiovascular disease.
Red wine again linked to slowing Alzheimer's.
Resveratrol, a compound found in grapes, red wine and peanuts, can improve blood flow in the brain by 30 per cent, thereby reducing the risk of stroke.
A study published in Journal of the American Geriatrics Society finds that moderate alcohol intake (1-2 drinks/day for 3-6 days/week, depending on alcoholic content) may lead to increased quality of life and survival in older women. The study found that non-drinkers and women who rarely drank had a significantly higher risk of dying during the survey period than did women who drank moderately. Of those who survived, the women who drank the least reported the lowest health-related quality of life.
Participants who drank on average half a glass, or 1.5 ounces, of wine per day, over a long period, had a 40 percent lower rate of all-cause death and a 48 percent lower incidence of cardiovascular death, compared to the non-wine drinkers. Researchers said life expectancy was 3.8 years higher in those men who drank wine compared to those who did not drink alcoholic beverages. Life expectancy of wine users was more than two years longer than users of other alcoholic beverages.
Women who regularly enjoy an alcoholic drink or two have a significantly lower risk of having a non-fatal heart attack than women who are life-time abstainers.
Alcohol may protect against rheumatoid arthritis (RA), with three units a week exhibiting protective effects and ten units a week being more protective still.
Drinking up to half a glass of wine a day may boost life expectancy by five years—at least in men—suggests research published ahead of print in the Journal of Epidemiology and Community Health.
A not-to-be missed- red wine summary here.
Moderate alcohol intake offers long-term cognitive protection and reduces the risk of dementia in older adults.
A study published in the Journal of Alzheimer's Disease suggests a protective effect of alcohol consumption on the risk of Alzheimer's disease, particularly in women who do not smoke.
More on red wine:
Red Wine
1. Drinking more than three glasses of red wine a week could cut the risk of colorectal cancer by almost 70 per cent.
2. Resveratrol, a polyphenol found in red wine, extended survival rates of mice and prevented the negative effects of high-calorie diets, says a new study. The study, described by an independent expert as potentially “the breakthrough of the year”, adds to a growing body of research linking resveratrol and red wine consumption to a range of beneficial health effects, including brain and mental health, and cardiovascular health.
3. Red wine and green tea halt prostate cancer growth
4. Drink Red Wine Daily For Best Results
5. Drinking Wine Protects Skin From Radiation
6. Lose Weight With Resveratrol?
“The physiological benefits of resveratrol are currently under intensive investigation, with recent work suggesting that it could be a good candidate for the development of obesity therapies.”
7. Resveratrol Neutralizes Toxicity of Proteins Related to Alzheimer's
According to one report: "Just one drink per day for women -- two for men -- could lead to small intestinal bacterial overgrowth (SIBO) and subsequently cause gastrointestinal symptoms like bloating, gas, abdominal pain, constipation and diarrhea."
Another report: Consumption of 3 to 6 alcoholic drinks per week is associated with a small increase in the risk of breast cancer...However, an individual will need to weigh the modest risks of light to moderate alcohol use on breast cancer development against the beneficial effects on cardiovascular disease to make the best personal choice regarding alcohol consumption."
I thought it might be useful in light of those recent reports to review some of the reported benefits of alcohol consumption:
Most recent reports:
Women who drink 15 grams or less of alcohol a day (the equivalent of one drink of any alcoholic beverage) at midlife may be healthier when older than women who do not drink at all, who consume more than two drinks a day, or who consume four drinks or more at the one time, according to a new study.
Among 13,894 women in the Nurses' Health Study, investigators prospectively examined alcohol use assessed at midlife in relation to "successful ageing," which was defined as survival to age 70 years, not having a major chronic disease (such as coronary disease, cancer, stroke, diabetes), and having no major cognitive impairment, physical impairment, or mental health problems. Only 11% of the women met these criteria.
The results indicate that moderate drinkers, especially those consuming wine and drinking regularly, were more likely to exhibit successful ageing. For average amount consumed, the largest benefit (an increase of 28%) was among women who reported 15.1 – 30 g of alcohol per day (an average of just over 1 to 2 ½ drinks per day), when compared with non-drinkers. The frequency of drinking was especially important: in comparison with nondrinkers, women who drank only on 1 to 2 days per week had little increase in their risk of successful ageing, but those drinking on at least 5 days per week had almost a 50% greater chance of successful ageing.
Older reports:
Men who drink alcohol every day have a lower risk of heart disease than those who drink less frequently, suggests research in the British Medical Journal.
A new study provides further evidence that alcohol, when consumed in moderation, reduces the risk of death, and not just that due to cardiovascular disease.
Red wine again linked to slowing Alzheimer's.
Resveratrol, a compound found in grapes, red wine and peanuts, can improve blood flow in the brain by 30 per cent, thereby reducing the risk of stroke.
A study published in Journal of the American Geriatrics Society finds that moderate alcohol intake (1-2 drinks/day for 3-6 days/week, depending on alcoholic content) may lead to increased quality of life and survival in older women. The study found that non-drinkers and women who rarely drank had a significantly higher risk of dying during the survey period than did women who drank moderately. Of those who survived, the women who drank the least reported the lowest health-related quality of life.
Participants who drank on average half a glass, or 1.5 ounces, of wine per day, over a long period, had a 40 percent lower rate of all-cause death and a 48 percent lower incidence of cardiovascular death, compared to the non-wine drinkers. Researchers said life expectancy was 3.8 years higher in those men who drank wine compared to those who did not drink alcoholic beverages. Life expectancy of wine users was more than two years longer than users of other alcoholic beverages.
Women who regularly enjoy an alcoholic drink or two have a significantly lower risk of having a non-fatal heart attack than women who are life-time abstainers.
Alcohol may protect against rheumatoid arthritis (RA), with three units a week exhibiting protective effects and ten units a week being more protective still.
Drinking up to half a glass of wine a day may boost life expectancy by five years—at least in men—suggests research published ahead of print in the Journal of Epidemiology and Community Health.
A not-to-be missed- red wine summary here.
Moderate alcohol intake offers long-term cognitive protection and reduces the risk of dementia in older adults.
A study published in the Journal of Alzheimer's Disease suggests a protective effect of alcohol consumption on the risk of Alzheimer's disease, particularly in women who do not smoke.
More on red wine:
Red Wine
1. Drinking more than three glasses of red wine a week could cut the risk of colorectal cancer by almost 70 per cent.
2. Resveratrol, a polyphenol found in red wine, extended survival rates of mice and prevented the negative effects of high-calorie diets, says a new study. The study, described by an independent expert as potentially “the breakthrough of the year”, adds to a growing body of research linking resveratrol and red wine consumption to a range of beneficial health effects, including brain and mental health, and cardiovascular health.
3. Red wine and green tea halt prostate cancer growth
4. Drink Red Wine Daily For Best Results
5. Drinking Wine Protects Skin From Radiation
6. Lose Weight With Resveratrol?
“The physiological benefits of resveratrol are currently under intensive investigation, with recent work suggesting that it could be a good candidate for the development of obesity therapies.”
7. Resveratrol Neutralizes Toxicity of Proteins Related to Alzheimer's
Thursday, November 3, 2011
Caucasians who avoid sun exposure more likely to be vitamin D deficient
Ω
Light-skinned people who avoid the sun are twice as likely to suffer from vitamin D deficiency as those who do not, according to a study of nearly 6,000 people by researchers at the Stanford University School of Medicine. Surprisingly, the use of sunscreen did not significantly affect blood levels of vitamin D, perhaps because users were applying too little or too infrequently, the researchers speculate.
The study adds to a growing debate about how to balance the dangers of sun exposure with the need for appropriate levels of vitamin D to prevent bone diseases such as osteoporosis and rickets.
"It's not as simple as telling everyone to wear sunscreen," said dermatologist Eleni Linos, MD PhD. "We may instead need to begin tailoring our recommendations to the skin tones and lifestyles of individual patients. It's clearly a very complex issue."
Linos, who is now an assistant professor of dermatology at the University of California-San Francisco, was a Stanford resident when the research was conducted. She is the first author of the research, which will be published online Nov. 4 in Cancer Causes and Control. Assistant professor of dermatology Jean Tang, MD, PhD, is the senior author.
Vitamin D is produced by the skin in response to exposure to the ultraviolet rays in sunlight; too little of the vitamin causes bone weakening and rickets and possibly contributes to many other chronic diseases including cancer. Small amounts of vitamin D can also be acquired by drinking fortified milk, eating fortified breakfast cereals or eating fatty fish such as salmon, tuna and mackerel, as well as from over-the-counter dietary supplements. Although it's not clear exactly how many people may be deficient in the vitamin, experts believe about 30 to 40 percent of the United States population may be affected.
Linos and Tang analyzed population-base data from the U.S. National Health and Nutrition Examination Survey collected by the Centers for Disease Control and Prevention from 2003 to 2006. The survey included questions about sun-protective behavior, inquiring whether respondents frequently wore long sleeves, hats and sunscreen, and whether they sought out shade on sunny days. It also included each respondent's race, as well as their blood levels of a form of vitamin D called 25-hydroxyvitamin D.
The researchers found that Caucasians who avoided the sun with clothing or stayed in the shade had blood levels of vitamin D that were about 3.5 and 2.2 nanograms per milliliter lower than those who did not report such behavior. In contrast, the association between sun avoidance and reductions in vitamin D levels in Hispanic or African-American survey-takers was not statistically significant. "This may be explained by the inherent pigmentation in darker skin, which acts as natural sun protection," said Linos. (The researchers did not analyze Asians as a separate group.)
The researchers considered any respondent with blood levels of 20 nanograms per milliliter or below to be vitamin D deficient because lower levels have been associated with adverse health outcomes. They found that although about 40 percent of all survey participants were vitamin D deficient, the prevalence increased to 53 and 56 percent among those who wore long sleeves and stayed in the shade. Whites who wore long sleeves and stayed in the shade were twice as likely to be deficient in the vitamin as those who did not (odds ratios of 2.16 and 2.11, respectively).
Race affects vitamin D production because of differences in skin pigmentation. Highly pigmented skin protects against ultraviolet rays, but also leads to lower overall baseline levels of vitamin D in the blood and frequent vitamin D deficiency. In the current study, African-Americans who rarely took sun-protective measures had an average vitamin D blood level of about 14.5 nanograms per milliliter. Hispanics who didn't avoid the sun had an average level of about 19.7 and sun-loving Caucasians, about 26.4. In contrast, those who frequently stayed in the shade had average levels of 14, 19.2 and 22.8 nanograms per milliliter, respectively.
"This confirms that the issue of vitamin D supplementation is increasingly important." said Linos. She cautioned, however, against wholesale use of dietary supplements before more data has been generated; currently there are two large, randomized clinical trials testing the health effects of relatively high doses of vitamin D.
The real surprise came when Linos found that the reported use of sunscreen did not significantly affect vitamin D levels. Because sunscreens block the ultraviolet rays that trigger the vitamin's production, it seems that regular usage should lower vitamin D in the blood.
"This finding was both interesting and surprising," said Linos. The apparent contradiction is likely due to sunscreen users not using the protection effectively. "People are probably not applying it often or thickly enough," she said. "Often, people use sunscreen when they anticipate getting a lot of sun exposure, unlike others who spend time in the shade in order to avoid the sun."
Light-skinned people who avoid the sun are twice as likely to suffer from vitamin D deficiency as those who do not, according to a study of nearly 6,000 people by researchers at the Stanford University School of Medicine. Surprisingly, the use of sunscreen did not significantly affect blood levels of vitamin D, perhaps because users were applying too little or too infrequently, the researchers speculate.
The study adds to a growing debate about how to balance the dangers of sun exposure with the need for appropriate levels of vitamin D to prevent bone diseases such as osteoporosis and rickets.
"It's not as simple as telling everyone to wear sunscreen," said dermatologist Eleni Linos, MD PhD. "We may instead need to begin tailoring our recommendations to the skin tones and lifestyles of individual patients. It's clearly a very complex issue."
Linos, who is now an assistant professor of dermatology at the University of California-San Francisco, was a Stanford resident when the research was conducted. She is the first author of the research, which will be published online Nov. 4 in Cancer Causes and Control. Assistant professor of dermatology Jean Tang, MD, PhD, is the senior author.
Vitamin D is produced by the skin in response to exposure to the ultraviolet rays in sunlight; too little of the vitamin causes bone weakening and rickets and possibly contributes to many other chronic diseases including cancer. Small amounts of vitamin D can also be acquired by drinking fortified milk, eating fortified breakfast cereals or eating fatty fish such as salmon, tuna and mackerel, as well as from over-the-counter dietary supplements. Although it's not clear exactly how many people may be deficient in the vitamin, experts believe about 30 to 40 percent of the United States population may be affected.
Linos and Tang analyzed population-base data from the U.S. National Health and Nutrition Examination Survey collected by the Centers for Disease Control and Prevention from 2003 to 2006. The survey included questions about sun-protective behavior, inquiring whether respondents frequently wore long sleeves, hats and sunscreen, and whether they sought out shade on sunny days. It also included each respondent's race, as well as their blood levels of a form of vitamin D called 25-hydroxyvitamin D.
The researchers found that Caucasians who avoided the sun with clothing or stayed in the shade had blood levels of vitamin D that were about 3.5 and 2.2 nanograms per milliliter lower than those who did not report such behavior. In contrast, the association between sun avoidance and reductions in vitamin D levels in Hispanic or African-American survey-takers was not statistically significant. "This may be explained by the inherent pigmentation in darker skin, which acts as natural sun protection," said Linos. (The researchers did not analyze Asians as a separate group.)
The researchers considered any respondent with blood levels of 20 nanograms per milliliter or below to be vitamin D deficient because lower levels have been associated with adverse health outcomes. They found that although about 40 percent of all survey participants were vitamin D deficient, the prevalence increased to 53 and 56 percent among those who wore long sleeves and stayed in the shade. Whites who wore long sleeves and stayed in the shade were twice as likely to be deficient in the vitamin as those who did not (odds ratios of 2.16 and 2.11, respectively).
Race affects vitamin D production because of differences in skin pigmentation. Highly pigmented skin protects against ultraviolet rays, but also leads to lower overall baseline levels of vitamin D in the blood and frequent vitamin D deficiency. In the current study, African-Americans who rarely took sun-protective measures had an average vitamin D blood level of about 14.5 nanograms per milliliter. Hispanics who didn't avoid the sun had an average level of about 19.7 and sun-loving Caucasians, about 26.4. In contrast, those who frequently stayed in the shade had average levels of 14, 19.2 and 22.8 nanograms per milliliter, respectively.
"This confirms that the issue of vitamin D supplementation is increasingly important." said Linos. She cautioned, however, against wholesale use of dietary supplements before more data has been generated; currently there are two large, randomized clinical trials testing the health effects of relatively high doses of vitamin D.
The real surprise came when Linos found that the reported use of sunscreen did not significantly affect vitamin D levels. Because sunscreens block the ultraviolet rays that trigger the vitamin's production, it seems that regular usage should lower vitamin D in the blood.
"This finding was both interesting and surprising," said Linos. The apparent contradiction is likely due to sunscreen users not using the protection effectively. "People are probably not applying it often or thickly enough," she said. "Often, people use sunscreen when they anticipate getting a lot of sun exposure, unlike others who spend time in the shade in order to avoid the sun."
Vegetarian diet, physical activity protect against diabetes
Ω
New research shows that following a vegetarian diet and exercising at least three times a week significantly reduced the risk of diabetes in African Americans, who are twice as likely to be diagnosed with diabetes when compared to non-Hispanic whites.
"These findings are encouraging for preventing type 2 diabetes in the black population, which is more susceptible to the disease than other populations," said Serena Tonstad, MD, a professor at Loma Linda University and lead author of the research, published in the October issue of Nutrition, Metabolism & Cardiovascular Diseases.
In addition to being at a greater risk for developing diabetes, black persons in the U.S. are also more likely to suffer from diabetes-related complications, such as end-stage renal disease and lower-extremity amputations, according to the U.S. Department of Health and Human Services.
"A vegetarian diet may be a way to counteract the increased diabetes risk for the black population," Dr. Tonstad said.
Dr. Tonstad's research showed that, compared to non-vegetarian blacks, vegan blacks had a 70 percent reduced risk of diabetes, and lacto-ovo vegetarian blacks (those who consume dairy, but no meat) had a 53 percent reduced risk of diabetes. Dr. Tonstad said one explanation was the protection associated with foods typically consumed in higher amounts in a vegetarian diet. Fruits and vegetables have a high fiber content, which may contribute to a decreased occurrence of type 2 diabetes. In addition, whole grains and legumes (beans) have been shown to improve glycemic control and slow the rate of carbohydrate absorption and the risk of diabetes.
The study also showed that black participants who exercised three or more times a week, compared to once a week or never, had a 35 percent reduced risk of diabetes.
The findings used prospective data (following persons over time) of 7,172 black Seventh-day Adventists participating in Adventist Health Study-2. Adventists are a Protestant religious group that promotes vegetarianism and advocates abstinence from tobacco and alcohol, which results in less confounding (distortions) when studying associations between diet and disease. Participants were given a questionnaire that asked how often they consumed 130 foods and food groups. Participants were then categorized into a dietary category (vegan, lacto-ovo vegetarian, etc.) based on their responses.
The study also analyzed data of 34,215 non-black Adventists and found similar protections against diabetes for a vegetarian diet. These findings confirm results from past cross-sectional research (examining persons at one point in time) that showed a vegetarian diet offered protection against diabetes.
New research shows that following a vegetarian diet and exercising at least three times a week significantly reduced the risk of diabetes in African Americans, who are twice as likely to be diagnosed with diabetes when compared to non-Hispanic whites.
"These findings are encouraging for preventing type 2 diabetes in the black population, which is more susceptible to the disease than other populations," said Serena Tonstad, MD, a professor at Loma Linda University and lead author of the research, published in the October issue of Nutrition, Metabolism & Cardiovascular Diseases.
In addition to being at a greater risk for developing diabetes, black persons in the U.S. are also more likely to suffer from diabetes-related complications, such as end-stage renal disease and lower-extremity amputations, according to the U.S. Department of Health and Human Services.
"A vegetarian diet may be a way to counteract the increased diabetes risk for the black population," Dr. Tonstad said.
Dr. Tonstad's research showed that, compared to non-vegetarian blacks, vegan blacks had a 70 percent reduced risk of diabetes, and lacto-ovo vegetarian blacks (those who consume dairy, but no meat) had a 53 percent reduced risk of diabetes. Dr. Tonstad said one explanation was the protection associated with foods typically consumed in higher amounts in a vegetarian diet. Fruits and vegetables have a high fiber content, which may contribute to a decreased occurrence of type 2 diabetes. In addition, whole grains and legumes (beans) have been shown to improve glycemic control and slow the rate of carbohydrate absorption and the risk of diabetes.
The study also showed that black participants who exercised three or more times a week, compared to once a week or never, had a 35 percent reduced risk of diabetes.
The findings used prospective data (following persons over time) of 7,172 black Seventh-day Adventists participating in Adventist Health Study-2. Adventists are a Protestant religious group that promotes vegetarianism and advocates abstinence from tobacco and alcohol, which results in less confounding (distortions) when studying associations between diet and disease. Participants were given a questionnaire that asked how often they consumed 130 foods and food groups. Participants were then categorized into a dietary category (vegan, lacto-ovo vegetarian, etc.) based on their responses.
The study also analyzed data of 34,215 non-black Adventists and found similar protections against diabetes for a vegetarian diet. These findings confirm results from past cross-sectional research (examining persons at one point in time) that showed a vegetarian diet offered protection against diabetes.
Physical activity = lower risk of depression in old age
Regular physical activity is associated with a lower risk of suffering depression in old age. This is shown by one of the largest studies on elderly Europeans to have been carried out, by researchers at the University of Gothenburg, Sweden, among others. Research also shows that self-determined motivation and perceived competence are i
"We do not yet know for sure what the causal relationship between physical activity and depression is like. What is clear is that elderly people who are physically active are less depressed, but higher levels of depression can also lead to less exercise, and this suggests there is a mutual influence," says Magnus Lindwall, docent (associate professor) in exercise and health psychology at the University of Gothenburg.
In a recently published study Lindwall, together with research colleagues, has studied 17,500 elderly people with an average age of 64 from 11 European countries who are taking part in the large EU-funded population study Survey of Health, Ageing and Retirement (SHARE). The subjects in the study were followed up over a period of two and a half years, among other things with regard to physical activity and depression.
"This study is one of the first to look at both how physical activity affects future depression and vice-versa, and how change in physical activity is associated with change in depression over time," says Lindwall.
"An important question for the researchers to answer has been what motivates elderly people to be physically active. Modern motivational theories propose, for example, that individuals who feel that they are competent, that they can take decisions for themselves and have freedom of choice and that they feel social relatedness linked to physical activity experience a more internal and a less controlled form of motivation for exercise. . This form of motivation, unlike a non-self-determining external form of motivation, is also associated with the maintenance of long-term regular physical activity, which also improves the prospects for the positive effects that physical activity can have on both physical and mental health.
"Right now we are developing and testing a structured programme to increase motivation for physical activity among the elderly based on the theories that today has strong support in the research," says Lindwall.
The results support the recommendations to use physical activity as a powerful preventive measure against mental ill-health in the elderly.
"But regular physical activity is required, otherwise there is a great risk of the long-term favourable effects on health being lost. It is therefore important to identify the barriers, for example depression, that prevent the elderly from being physically active and focus on how to increase the motivation of elderly people for physical activity," says Lindwall.
"We do not yet know for sure what the causal relationship between physical activity and depression is like. What is clear is that elderly people who are physically active are less depressed, but higher levels of depression can also lead to less exercise, and this suggests there is a mutual influence," says Magnus Lindwall, docent (associate professor) in exercise and health psychology at the University of Gothenburg.
In a recently published study Lindwall, together with research colleagues, has studied 17,500 elderly people with an average age of 64 from 11 European countries who are taking part in the large EU-funded population study Survey of Health, Ageing and Retirement (SHARE). The subjects in the study were followed up over a period of two and a half years, among other things with regard to physical activity and depression.
"This study is one of the first to look at both how physical activity affects future depression and vice-versa, and how change in physical activity is associated with change in depression over time," says Lindwall.
"An important question for the researchers to answer has been what motivates elderly people to be physically active. Modern motivational theories propose, for example, that individuals who feel that they are competent, that they can take decisions for themselves and have freedom of choice and that they feel social relatedness linked to physical activity experience a more internal and a less controlled form of motivation for exercise. . This form of motivation, unlike a non-self-determining external form of motivation, is also associated with the maintenance of long-term regular physical activity, which also improves the prospects for the positive effects that physical activity can have on both physical and mental health.
"Right now we are developing and testing a structured programme to increase motivation for physical activity among the elderly based on the theories that today has strong support in the research," says Lindwall.
The results support the recommendations to use physical activity as a powerful preventive measure against mental ill-health in the elderly.
"But regular physical activity is required, otherwise there is a great risk of the long-term favourable effects on health being lost. It is therefore important to identify the barriers, for example depression, that prevent the elderly from being physically active and focus on how to increase the motivation of elderly people for physical activity," says Lindwall.
Subscribe to:
Posts (Atom)