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Exercise can buffer the effects of stress-induced cell aging, according to new research from UCSF that revealed actual benefits of physical activity at the cellular level.
The scientists learned that vigorous physical activity as brief as 42 minutes over a 3-day period, similar to federally recommended levels, can protect individuals from the effects of stress by reducing its impact on telomere length. Telomeres (pronounced TEEL-oh-meres) are tiny pieces of DNA that promote genetic stability and act as protective sheaths by keeping chromosomes from unraveling, much like plastic tips at the ends of shoelaces.
A growing body of research suggests that short telomeres are linked to a range of health problems, including coronary heart disease and diabetes, as well as early death.
"Telomere length is increasingly considered a biological marker of the accumulated wear and tear of living, integrating genetic influences, lifestyle behaviors, and stress,'' said Elissa Epel, PhD, who is one of the lead investigators and an associate professor in the UCSF Department of Psychiatry. "Even a moderate amount of vigorous exercise appears to provide a critical amount of protection for the telomeres."
The findings build on previous UCSF research documenting that chronic psychological stress takes a significant toll on the human body by impacting the length of telomeres in immune cells. While the exact mechanisms have remained elusive, a UCSF-led research study in 2004 (PNAS, Dec. 7, 2004; 101 (49) found that the ramifications of stress stretch deep into our cells, affecting telomeres, which are believed to play a key role in cellular aging, and possibly disease development.
The findings also build on previous studies showing that exercise is linked to longer telomeres, but this is the first study to show that exercise -- acting as a "stress-buffer'' – can prevent the shortening of telomeres due to stress.
Research on telomeres, and the enzyme that makes them, was pioneered by three Americans, including UCSF molecular biologist Elizabeth Blackburn, PhD, who co-discovered the telomerase enzyme in 1985. The scientists received the Nobel Prize in Physiology or Medicine in 2009.
"We are at the tip of the iceberg in our understanding of which lifestyle factors affect telomere maintenance, and how,'' noted Blackburn.
The new study, in which Blackburn is a co-author, is scheduled for publication May 26, 2010 in the peer-reviewed online publication PLoS ONE.
In the study, 62 post-menopausal women – many of whom were caring for spouses or parents with dementia -- reported at the end of each day over three days the number of minutes of vigorous physical activity in which they had engaged. Vigorous activity in the study was defined as "increased heart rate and/or sweating.'' They also reported separately their perceptions of life stress that they had experienced during the prior month. Their blood's immune cells were examined for telomere length.
Results support the UCSF-led discovery six years earlier in premenopausal women that psychological stress has a detrimental effect on immune cell longevity, as it relates to shorter telomeres. The new study showed, however, that when participants were divided into groups – an inactive group, and an active group (i.e., they met federal recommendations for 75 minutes of weekly physical activity) – only the inactive high stress group had shorter telomeres. The active high stress group did not have shorter telomeres. In other words, stress predicted shorter telomeres in the sedentary group, but not in the active group.
The Centers for Disease Control and Prevention (CDC) suggests 75 minutes of vigorous activity a week for adults, or 150 minutes of moderate activity in addition to weight-bearing exercises. For children and adolescents, recommended levels are 90 minutes per day. For this sample of older women, it appears that the CDC-recommended level of vigorous exercise for adults may be enough to buffer the effects of stress on telomeres. However, the researchers say, this finding needs to be replicated with larger samples.
"At this point, we have replicated previous findings showing a link between life stress and the dynamics of how cells age,'' said lead author Eli Puterman, PhD, a psychologist in the UCSF Department of Psychiatry. "Yet we have extended those findings to show that, in fact, there are things we can do about it. If we maintain the levels of physical activity recommended, at least those put forth by the CDC, we can prevent the unyielding damage that psychological stress may have on our body.''
"Our findings also reveal that those who reported more stress were less likely to exercise over the course of the study,'' he said. "While this finding may be discouraging, it offers a great opportunity to direct research to specifically examine these vulnerable stressed individuals to find ways to engage them in greater physical activity.''
UCSF co-authors of the study reported in PLoS ONE include Jue Lin, PhD, a postdoctoral fellow in the Department of Biochemistry and Biophysics; Aoife O'Donovan, PhD, a postdoctoral scholar in the Department of Psychiatry; and Nancy Adler, PhD, a professor and vice chair in the Department of Psychiatry.
The research was supported by the National Institute of Aging, the Bernard and Barbro Fund, the UCSF-GIVI Center for AIDS Research, and a NIH/NCRR UCSF-CTSI grant. The contents of the published paper are solely the responsibility of the authors and do not necessarily represent the official views of any of the granting agencies. Drs. Blackburn, Epel, and Lin are co-founders of a company to measure telomere maintenance.
The UCSF researchers are now embarking on another research project in which participants will learn their own telomere length. The scientists will test whether discovering one's personal telomere length will motivate people to make lifestyle changes such as exercising more, reducing stress and eating less processed red meat, all factors that have been linked to telomere length.
Thursday, May 27, 2010
Milk: 2 glasses a day tones muscles, keeps the fat away in women, study shows
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Women who drink two large glasses of milk a day after their weight-lifting routine gained more muscle and lost more fat compared to women who drank sugar-based energy drinks, a McMaster study has found.
The study appears in the June issue of Medicine and Science in Sport and Exercise.
"Resistance training is not a typical choice of exercise for women," says Stu Phillips, professor in the Department of Kinesiology at McMaster University. "But the health benefits of resistance training are enormous: It boosts strength, bone, muscular and metabolic health in a way that other types of exercise cannot."
A previous study conducted by Phillips' lab showed that milk increased muscle mass and fat loss in men. This new study, says Phillips was more challenging because women not only steer clear of resistance training they also tend to steer away from dairy products based on the incorrect belief that dairy foods are fattening.
"We expected the gains in muscle mass to be greater, but the size of the fat loss surprised us," says Phillips. "We're still not sure what causes this but we're investigating that now. It could be the combination of calcium, high-quality protein, and vitamin D may be the key, and. conveniently, all of these nutrients are in milk.
Over a 12-week period, the study monitored young women who did not use resistance-training exercise. Every day, two hours before exercising, the women were required not to eat or drink anything except water. Immediately after their exercise routine, one group consumed 500ml of fat free white milk; the other group consumed a similar-looking but sugar-based energy drink. The same drinks were consumed by each group one hour after exercising.
The training consisted of three types of exercise: pushing (e.g. bench press, chest fly), pulling (e.g. seated lateral pull down, abdominal exercises without weights), and leg exercises (e.g. leg press, seated two-leg hamstring curl). Training was monitored daily one on one by personal trainers to ensure proper technique.
"The women who drank milk gained barely any weight because what they gained in lean muscle they balanced out with a loss in fat" said Phillips. "Our data show that simple things like regular weightlifting exercise and milk consumption work to substantially improve women's body composition and health." Phillips' lab is now following this study up with a large clinical weight loss trial in women.
Women who drink two large glasses of milk a day after their weight-lifting routine gained more muscle and lost more fat compared to women who drank sugar-based energy drinks, a McMaster study has found.
The study appears in the June issue of Medicine and Science in Sport and Exercise.
"Resistance training is not a typical choice of exercise for women," says Stu Phillips, professor in the Department of Kinesiology at McMaster University. "But the health benefits of resistance training are enormous: It boosts strength, bone, muscular and metabolic health in a way that other types of exercise cannot."
A previous study conducted by Phillips' lab showed that milk increased muscle mass and fat loss in men. This new study, says Phillips was more challenging because women not only steer clear of resistance training they also tend to steer away from dairy products based on the incorrect belief that dairy foods are fattening.
"We expected the gains in muscle mass to be greater, but the size of the fat loss surprised us," says Phillips. "We're still not sure what causes this but we're investigating that now. It could be the combination of calcium, high-quality protein, and vitamin D may be the key, and. conveniently, all of these nutrients are in milk.
Over a 12-week period, the study monitored young women who did not use resistance-training exercise. Every day, two hours before exercising, the women were required not to eat or drink anything except water. Immediately after their exercise routine, one group consumed 500ml of fat free white milk; the other group consumed a similar-looking but sugar-based energy drink. The same drinks were consumed by each group one hour after exercising.
The training consisted of three types of exercise: pushing (e.g. bench press, chest fly), pulling (e.g. seated lateral pull down, abdominal exercises without weights), and leg exercises (e.g. leg press, seated two-leg hamstring curl). Training was monitored daily one on one by personal trainers to ensure proper technique.
"The women who drank milk gained barely any weight because what they gained in lean muscle they balanced out with a loss in fat" said Phillips. "Our data show that simple things like regular weightlifting exercise and milk consumption work to substantially improve women's body composition and health." Phillips' lab is now following this study up with a large clinical weight loss trial in women.
Some statins have unintended effects and warrant closer monitoring
The type and dosage of statin drugs given to patients to treat heart disease should be proactively monitored as they can have unintended adverse effects, concludes a new study published on bmj.com.
Researchers at The University of Nottingham found that some statins can lead to an increased risk of liver dysfunction, acute renal failure, myopathy and cataracts in patients.
Cardiovascular disease is a leading cause of premature death and a major cause of disability in the UK. The use of statins is often recommended to reduce the risk of cardiovascular disease among high risk patients.
Julia Hippisley-Cox, professor of clinical epidemiology and general practice, and Carol Coupland, associate professor in medical statistics, both at The University of Nottingham, wanted to measure the unintended effects of statins on certain clinical outcomes, taking into account the type, dose and duration of use.
They studied data collected from 368 general practices contributing to the QResearch database on 2,004,692 patients aged 30-84 years including 225,922 patients who were new statin users and prescribed a range of statins. The patients’ adverse outcomes were studied from January 2002 to June 2008.
The researchers estimated the effects of type, dose and duration of statin use on clinical outcomes that have been associated previously with statins and then calculated the numbers needed to treat and harm.
They found there was no significant association between use of individual statins and risk of Parkinson’s disease, rheumatoid arthritis, venous thrombo-embolism, dementia, osteoporotic fracture, or many cancers including gastric, colon, lung, renal, breast or prostate. There was a reduced risk associated with statin use for oesophageal cancer.
There was, however, an increased risk associated with using statins for moderate or serious liver dysfunction, acute renal failure, moderate to serious myopathy and cataracts and evidence of a dose response for acute renal failure and liver dysfunction with higher doses being associated with greater risk.
Adverse effects were similar for all of the different statins taken except for liver dysfunction, where the highest risks were found for fluvastatin. All of the increased risks persisted during the treatment, but were highest in the first year.
Overall, for every 10,000 high risk women treated with statins, there would be approximately 271 fewer cases of cardiovascular disease, 8 fewer cases of oesophageal cancer; 74 extra patients who experience liver dysfunction; 23 extra patients with acute renal failure, 307 extra patients with cataracts, and 39 extra patients with myopathy. Similar figures were found for men except rates of myopathy were higher.
Some of the effects might be due to better detection rates since patients taking statins will consult their doctor more.
Researchers at The University of Nottingham found that some statins can lead to an increased risk of liver dysfunction, acute renal failure, myopathy and cataracts in patients.
Cardiovascular disease is a leading cause of premature death and a major cause of disability in the UK. The use of statins is often recommended to reduce the risk of cardiovascular disease among high risk patients.
Julia Hippisley-Cox, professor of clinical epidemiology and general practice, and Carol Coupland, associate professor in medical statistics, both at The University of Nottingham, wanted to measure the unintended effects of statins on certain clinical outcomes, taking into account the type, dose and duration of use.
They studied data collected from 368 general practices contributing to the QResearch database on 2,004,692 patients aged 30-84 years including 225,922 patients who were new statin users and prescribed a range of statins. The patients’ adverse outcomes were studied from January 2002 to June 2008.
The researchers estimated the effects of type, dose and duration of statin use on clinical outcomes that have been associated previously with statins and then calculated the numbers needed to treat and harm.
They found there was no significant association between use of individual statins and risk of Parkinson’s disease, rheumatoid arthritis, venous thrombo-embolism, dementia, osteoporotic fracture, or many cancers including gastric, colon, lung, renal, breast or prostate. There was a reduced risk associated with statin use for oesophageal cancer.
There was, however, an increased risk associated with using statins for moderate or serious liver dysfunction, acute renal failure, moderate to serious myopathy and cataracts and evidence of a dose response for acute renal failure and liver dysfunction with higher doses being associated with greater risk.
Adverse effects were similar for all of the different statins taken except for liver dysfunction, where the highest risks were found for fluvastatin. All of the increased risks persisted during the treatment, but were highest in the first year.
Overall, for every 10,000 high risk women treated with statins, there would be approximately 271 fewer cases of cardiovascular disease, 8 fewer cases of oesophageal cancer; 74 extra patients who experience liver dysfunction; 23 extra patients with acute renal failure, 307 extra patients with cataracts, and 39 extra patients with myopathy. Similar figures were found for men except rates of myopathy were higher.
Some of the effects might be due to better detection rates since patients taking statins will consult their doctor more.
Tuesday, May 25, 2010
Link between sugar in drinks and blood pressure
Research led by Liwei Chen, MD, PhD, Assistant Professor of Public Health at LSU Health Sciences Center New Orleans, has found that there is an association between sugary drinks and blood pressure and that by cutting daily consumption of sugary drinks by just one serving a day, people can lower their blood pressure. The research is published online in Circulation: Journal of the American Heart Association.
"We found no association for diet beverage consumption or caffeine intake and blood pressure," notes Dr. Chen, "suggesting that sugar may actually be the nutrient that is associated with blood pressure and not caffeine which many people would suspect."
The research, which was supported by a grant from the National Heart, Lung, and Blood Institute of the National Institutes of Health, analyzed dietary intake and blood pressure of 810 adults measured at baseline, 6 and 18 months. After known risk factors of high blood pressure were controlled for, a reduction in sugar-sweetened beverage consumption of one serving per day was associated with a drop of 1.8 mm Hg in systolic pressure and 1.1 mm Hg in diastolic blood pressure over 18 months.
After additional adjustment for weight change over the same period, a reduction in the consumption of sugar-sweetened beverages was still significantly associated with blood pressure reduction.
"By reducing the amount of sugar in your diet, you are also reducing the number of calories you consume and may lose weight," adds Dr. Chen. "But even among those whose weight was stable, we still found that people who drank fewer sugary sodas lowered their blood pressure."
Elevated blood pressure continues to be one of the most common and important problems in the United States. According to the American Heart Association, about 74.5 million people in the United States, or one in three people, age 20 and older have high blood pressure. It is estimated that high blood pressure killed 56,561Americans in 2006. From 1996 to 2006, the death rate from high blood pressure increased 19.5 percent, and the actual number of deaths rose 48.1 percent.
Normal blood pressure, measured in millimeters of mercury, is defined as systolic (top number) less than 120 and diastolic (bottom number) less than 80. High blood pressure (hypertension) is a systolic pressure of 140 or higher and a diastolic pressure of 90 or higher. Pressures falling in the range between are considered to be prehypertension.
High blood pressure, which usually has few symptoms, if any, is an established risk factor for stroke, cardiovascular disease, kidney failure, and shortened life expectancy.
"More research is needed to establish the causal relationship, but in the meantime, people can benefit right now by reducing their intake of sugary drinks by at least one serving per day," concludes Dr. Chen.
"We found no association for diet beverage consumption or caffeine intake and blood pressure," notes Dr. Chen, "suggesting that sugar may actually be the nutrient that is associated with blood pressure and not caffeine which many people would suspect."
The research, which was supported by a grant from the National Heart, Lung, and Blood Institute of the National Institutes of Health, analyzed dietary intake and blood pressure of 810 adults measured at baseline, 6 and 18 months. After known risk factors of high blood pressure were controlled for, a reduction in sugar-sweetened beverage consumption of one serving per day was associated with a drop of 1.8 mm Hg in systolic pressure and 1.1 mm Hg in diastolic blood pressure over 18 months.
After additional adjustment for weight change over the same period, a reduction in the consumption of sugar-sweetened beverages was still significantly associated with blood pressure reduction.
"By reducing the amount of sugar in your diet, you are also reducing the number of calories you consume and may lose weight," adds Dr. Chen. "But even among those whose weight was stable, we still found that people who drank fewer sugary sodas lowered their blood pressure."
Elevated blood pressure continues to be one of the most common and important problems in the United States. According to the American Heart Association, about 74.5 million people in the United States, or one in three people, age 20 and older have high blood pressure. It is estimated that high blood pressure killed 56,561Americans in 2006. From 1996 to 2006, the death rate from high blood pressure increased 19.5 percent, and the actual number of deaths rose 48.1 percent.
Normal blood pressure, measured in millimeters of mercury, is defined as systolic (top number) less than 120 and diastolic (bottom number) less than 80. High blood pressure (hypertension) is a systolic pressure of 140 or higher and a diastolic pressure of 90 or higher. Pressures falling in the range between are considered to be prehypertension.
High blood pressure, which usually has few symptoms, if any, is an established risk factor for stroke, cardiovascular disease, kidney failure, and shortened life expectancy.
"More research is needed to establish the causal relationship, but in the meantime, people can benefit right now by reducing their intake of sugary drinks by at least one serving per day," concludes Dr. Chen.
Being Overweight Brings No Extra Health Problems
A study examining the relationship between body mass index (BMI) and illness suggests that a BMI of 30 or above, a signal of obesity according to federal health standards, does not translate into current illness among adults under age 40.
For college-age adults, this should help them realize that they don’t have to worry so much if they have a BMI of 27 or 28. Some young people with these BMIs feel like, ‘I’m going to have all these problems, I need to try 50 different diets.’ And what is all that stress and dieting doing to your body? Probably more damage than the extra 15 pounds is.”
In addition, researchers found that across all age groups studied, from 25 to 70 years, there was little difference in the current health status in normal-weight vs. overweight people based on the medications they took.
Body mass index is a common health measure of weight relative to height. According to the National Heart, Lung and Blood Institute, a BMI between 18.5 and 24.9 indicates normal weight and a BMI between 25 and 29.9 falls into the overweight range. A BMI of 30 or higher indicates obesity.
The researchers acknowledge that health problems in older adults with BMIs of 30 or higher might be traced back to carrying extra weight in young adulthood. Among people age 40 or older, use of medication was significantly higher among adults considered to be obese compared to adults with a normal weight.
For college-age adults, this should help them realize that they don’t have to worry so much if they have a BMI of 27 or 28. Some young people with these BMIs feel like, ‘I’m going to have all these problems, I need to try 50 different diets.’ And what is all that stress and dieting doing to your body? Probably more damage than the extra 15 pounds is.”
However, the large population study suggested that people with a BMI in the overweight range are generally not at a higher risk for current health problems compared to people of normal weight, regardless of age.
“A lot of people make a big deal about those overweight BMIs, but we didn’t see a difference between overweight and normal-weight adults across all age groups in the percentage of people medicated, or in the number of medications taken,” said Brant Jarrett, lead author of the study and a doctoral student in neuroscience at Ohio State University.
“For college-age adults, this should help them realize that they don’t have to worry so much if they have a BMI of 27 or 28. Some young people with these BMIs feel like, ‘I’m going to have all these problems, I need to try 50 different diets.’ And what is all that stress and dieting doing to your body? Probably more damage than the extra 15 pounds is,” Jarrett said.
The study also upholds previous findings that more women than men take medication, but does not indicate why that is. Interestingly, that gender difference disappears in adults age 55 and older.
Jarrett conducted the research with colleagues while he was a graduate student at Brigham Young University. The work is published in a recent issue of the International Journal of Obesity.
Jarrett noticed during his studies on stress that many people, especially college students, said being overweight was one of their main stressors.
“We wanted to see at what point being overweight is a real physical stressor instead of a psychological stressor. Most studies on BMI look at risk factors, which do not assess current health. That’s health risk. So we wanted to see if a higher BMI is associated with current physical health problems,” he said.
Health experts say that people with BMIs in the overweight or obese range have a higher risk for developing Type 2 diabetes, high blood pressure and cardiovascular disease than do individuals in a normal weight range.
The researchers collected data from National Health and Nutrition Examination Survey U.S. adult population databases covering three time periods: 1988-94, 2003-04 and 2005-06. They collected data on BMI, age, gender and current medication use among 9,071 women and 8,880 men, separating them into three age groups: 25 to 39, 40 to 54 and 55 to 70. Adults with a BMI below 19.5 were excluded.
To identify the levels of illness among these populations, Jarrett and colleagues examined the use of prescribed medications. Before collecting the data, they analyzed hundreds of drugs on the market, ruling out medications typically used to treat mental health disorders as well as drugs used to treat conditions that are not associated with physical illness.
“We had access to information on specifically what people were taking, how many people were taking these medications and the reason they were taking them” Jarrett said.
“We then used these doctors’ reports of prescribed medication use as an estimate for illness burden based on the assumption that these drugs represented diagnosed illnesses or symptoms considered by doctors serious enough to warrant treatment.”
Across the board, BMI levels and the percentage of adults taking medication increased from the 1988-94 to the 2003-06 time frame, reinforcing public health concerns about a growing incidence of obesity in the United States, Jarrett noted.
Both the percentage of people taking medications and the number of medications taken also increased from the 1988-94 period to the 2003-06 period, but only among people age 40 to 70, and not in the younger age group.
After applying a number of statistical tests to the data, the researchers found that among all age groups, with few exceptions, there was no significant difference in the severity of illness between those with normal weight and overweight BMIs. There was a slight increase in the percentage of medication use among men age 40 to 70 with overweight BMIs when compared to men of normal weight.
“Thus, having a BMI in the overweight range, by itself, was not generally associated with an increased medication load,” Jarrett said.
In addition, a higher BMI had less of an impact on medication use in younger people than it did in the two older age groups – a sign to the researchers that the age of onset of a high BMI should factor into assessments of health risk, especially in young people.
Jarrett said the emphasis on BMI can have damaging psychological effects on young people who, this study suggests, typically do not have health problems related to their weight. Though the BMI is convenient, it doesn’t take into account different body types or gender differences; a measure of body fat percentage would offer a more accurate picture of risks associated with an individual’s weight, he said.
“I think that the effects of BMI on health have more to do with the stress effects on health than the weight-related effects on health, especially in those with a BMI of 25 to30,” he said. “At a young age you’re fine, health-wise, even with a high BMI, but who worries most about BMI? Young people. It’s something they think about every single day, every time they put on their clothes and every time they look in the mirror.”
On the other hand, obesity was associated with a significant increase in medication use among adults age 40 to 70. For example, almost 70 percent of obese women age 40 to 54 were taking medication in the later time frame, compared to about 57 percent of women with a normal weight. Among men of the same age in the same time frame, medication use was 61 percent and 39 percent, respectively.
These figures also speak to the higher percentage of women than men taking medication and taking more medicines than men, a trend seen in this study as well as previous research. Scientists can only theorize about why this is, Jarrett noted.
As for the overall increased medication use among older adults in the more recent group (2003-2006), Jarrett suggested that this trend could relate to an increase in illness associated with the overall increase in BMI over time or could be attributed to more aggressive physician approaches to treatments that accompany advances in technology.
More “Good” Cholesterol is Not Always Good for Your Health
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HDL cholesterol can transform from good to bad actor in heart disease process
We’ve all heard about the importance of raising HDL, or the so-called “good” cholesterol, and lowering LDL, or “bad” cholesterol, to improve heart health. While we’ve come to assume HDL cholesterol is an inherently good thing, a new study shows that for a certain group of patients, this is not always the case. The study is the first to find that a high level of the supposedly good cholesterol places a subgroup of patients at high risk for recurrent coronary events, such as chest pain, heart attack, and death.
The findings, published in Arteriosclerosis, Thrombosis, and Vascular Biology, a journal of the American Heart Association, could help explain disappointing results from a high-profile Pfizer clinical trial testing torcetrapib, an experimental drug designed to increase levels of HDL cholesterol, that some predicted would become a blockbuster medicine. The trial was halted in 2006 due to a surprisingly excessive number of cardiovascular events and death. As in the current study, cardiovascular events in the torcetrapib trial were associated with higher levels of “good” HDL cholesterol, though the reasons were unclear.
“It seems counterintuitive that increasing good cholesterol, which we’ve always thought of as protective, leads to negative consequences in some people,” said James Corsetti, M.D., Ph.D., professor of Pathology and Laboratory Medicine at the University of Rochester Medical Center and lead author of the study. “We’ve confirmed that high HDL cholesterol is in fact associated with risk in a certain group of patients.”
Using a novel graphical data mapping tool – outcome event mapping – Corsetti and his team identified a group of patients in which elevated levels of HDL cholesterol place them in a high-risk category for coronary events.
“The ability to identify patients who will not benefit from efforts to increase HDL cholesterol is important because they can be excluded from trials testing medications that aim to raise HDL cholesterol,” said Charles Sparks, M.D., professor of Pathology and Laboratory Medicine and co-author of the study. “With these patients excluded, researchers may find that raising HDL cholesterol in the remaining population is effective in reducing cardiovascular disease risk.”
Despite the outcome of the Pfizer torcetrapib trial and findings in the existing literature, including the current study, that suggest high HDL cholesterol can be a bad thing, drug companies remain invested in identifying drugs to increase HDL cholesterol. Merck recently announced plans to launch a major clinical trial in 2011 to test whether anacetrapib – a molecular cousin to torcetrapib designed to raise good cholesterol – reduces the risk of heart attack and death.
Patients in the high-risk subgroup were characterized as having high levels of C-reactive protein (CRP), a well-known marker of inflammation, in addition to high HDL cholesterol. Study authors believe genetics and environmental factors, particularly inflammation, influence whether high levels of HDL cholesterol are protective or if they increase cardiovascular risk in individual patients. Given an inflammatory environment, an individual’s unique set of genes helps determine whether HDL cholesterol transforms from a good actor to a bad actor in the heart disease process.
In the high-risk subgroup of patients with elevated HDL cholesterol and CRP, researchers also identified two genetic factors associated with recurrent coronary events. The activity of cholesterol ester transfer protein (CETP), which moves cholesterol away from the vascular system and is associated with HDL cholesterol, and p22phox, which influences inflammation-related processes and is associated with CRP, are both risk predictors in this subgroup of patients.
“Our research is oriented around the ability to better identify patients at high risk,” said Corsetti. “Identifying these patients and determining what puts them at high risk may be useful in choosing treatments tailored to the specific needs of particular patient subgroups. This gets us another step closer to achieving the goal of personalized medicine.”
Corsetti’s team identified individuals at high risk for recurrent coronary events among 767 non-diabetic patients who experienced at least one prior heart attack. About 20 percent of the total study population was in the subgroup having high-risk with high HDL cholesterol and CRP. Outcome event maps plot risk over an area defined by high and low levels of two biomarkers, in this case HDL cholesterol and CRP. Peaks and valleys in the maps correspond to high- and low-risk patient subgroups. Patients were followed for recurrent events for approximately two years and were part of the Thrombogenic Factors and Recurrent Coronary Events (THROMBO) study led by cardiologist Arthur Moss, M.D., professor of Medicine at the University of Rochester Medical Center and study co-author.
The current results parallel findings from a study of a healthy population. The Prevention of Renal and Vascular End-Stage Disease (PREVEND) study also identified a high-risk subgroup of patients with elevated HDL cholesterol and CRP levels among individuals who had no prior coronary events.
In addition to Corsetti, Sparks, and Moss, Dan Ryan, M.D., and Wojciech Zareba, M.D., Ph.D. from the University of Rochester Medical Center and David Rainwater, Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, Texas participated in the study. The study was funded by the National Heart, Lung and Blood Institute at the National Institutes of Health.
HDL cholesterol can transform from good to bad actor in heart disease process
We’ve all heard about the importance of raising HDL, or the so-called “good” cholesterol, and lowering LDL, or “bad” cholesterol, to improve heart health. While we’ve come to assume HDL cholesterol is an inherently good thing, a new study shows that for a certain group of patients, this is not always the case. The study is the first to find that a high level of the supposedly good cholesterol places a subgroup of patients at high risk for recurrent coronary events, such as chest pain, heart attack, and death.
The findings, published in Arteriosclerosis, Thrombosis, and Vascular Biology, a journal of the American Heart Association, could help explain disappointing results from a high-profile Pfizer clinical trial testing torcetrapib, an experimental drug designed to increase levels of HDL cholesterol, that some predicted would become a blockbuster medicine. The trial was halted in 2006 due to a surprisingly excessive number of cardiovascular events and death. As in the current study, cardiovascular events in the torcetrapib trial were associated with higher levels of “good” HDL cholesterol, though the reasons were unclear.
“It seems counterintuitive that increasing good cholesterol, which we’ve always thought of as protective, leads to negative consequences in some people,” said James Corsetti, M.D., Ph.D., professor of Pathology and Laboratory Medicine at the University of Rochester Medical Center and lead author of the study. “We’ve confirmed that high HDL cholesterol is in fact associated with risk in a certain group of patients.”
Using a novel graphical data mapping tool – outcome event mapping – Corsetti and his team identified a group of patients in which elevated levels of HDL cholesterol place them in a high-risk category for coronary events.
“The ability to identify patients who will not benefit from efforts to increase HDL cholesterol is important because they can be excluded from trials testing medications that aim to raise HDL cholesterol,” said Charles Sparks, M.D., professor of Pathology and Laboratory Medicine and co-author of the study. “With these patients excluded, researchers may find that raising HDL cholesterol in the remaining population is effective in reducing cardiovascular disease risk.”
Despite the outcome of the Pfizer torcetrapib trial and findings in the existing literature, including the current study, that suggest high HDL cholesterol can be a bad thing, drug companies remain invested in identifying drugs to increase HDL cholesterol. Merck recently announced plans to launch a major clinical trial in 2011 to test whether anacetrapib – a molecular cousin to torcetrapib designed to raise good cholesterol – reduces the risk of heart attack and death.
Patients in the high-risk subgroup were characterized as having high levels of C-reactive protein (CRP), a well-known marker of inflammation, in addition to high HDL cholesterol. Study authors believe genetics and environmental factors, particularly inflammation, influence whether high levels of HDL cholesterol are protective or if they increase cardiovascular risk in individual patients. Given an inflammatory environment, an individual’s unique set of genes helps determine whether HDL cholesterol transforms from a good actor to a bad actor in the heart disease process.
In the high-risk subgroup of patients with elevated HDL cholesterol and CRP, researchers also identified two genetic factors associated with recurrent coronary events. The activity of cholesterol ester transfer protein (CETP), which moves cholesterol away from the vascular system and is associated with HDL cholesterol, and p22phox, which influences inflammation-related processes and is associated with CRP, are both risk predictors in this subgroup of patients.
“Our research is oriented around the ability to better identify patients at high risk,” said Corsetti. “Identifying these patients and determining what puts them at high risk may be useful in choosing treatments tailored to the specific needs of particular patient subgroups. This gets us another step closer to achieving the goal of personalized medicine.”
Corsetti’s team identified individuals at high risk for recurrent coronary events among 767 non-diabetic patients who experienced at least one prior heart attack. About 20 percent of the total study population was in the subgroup having high-risk with high HDL cholesterol and CRP. Outcome event maps plot risk over an area defined by high and low levels of two biomarkers, in this case HDL cholesterol and CRP. Peaks and valleys in the maps correspond to high- and low-risk patient subgroups. Patients were followed for recurrent events for approximately two years and were part of the Thrombogenic Factors and Recurrent Coronary Events (THROMBO) study led by cardiologist Arthur Moss, M.D., professor of Medicine at the University of Rochester Medical Center and study co-author.
The current results parallel findings from a study of a healthy population. The Prevention of Renal and Vascular End-Stage Disease (PREVEND) study also identified a high-risk subgroup of patients with elevated HDL cholesterol and CRP levels among individuals who had no prior coronary events.
In addition to Corsetti, Sparks, and Moss, Dan Ryan, M.D., and Wojciech Zareba, M.D., Ph.D. from the University of Rochester Medical Center and David Rainwater, Department of Genetics, Southwest Foundation for Biomedical Research, San Antonio, Texas participated in the study. The study was funded by the National Heart, Lung and Blood Institute at the National Institutes of Health.
Statins
I had an opportunity to discuss statins with my doctor recently. I had been taking a statin substitute (red yeast rice) but stopped because of concerns about possible liver damage - he advised that that was extremely rare and I should not worry about it, although we will review my liver enzyme report at my next appointment. We discussed that statins are now being approved even for people w/o high cholesterol (see below.) He told me that he now takes a statin!
So I'm hoping he will prescribe one for me at my next appointment - and I will continue taking red yeast rice with co-enzyme Q-10 whiich should help avoid muscle problems.)
The evidence about all the good things statins do is overwhelming - as outlined below:
WHAT YOU SHOULD KNOW ABOUT STATINS
Statins must be taken regularly to maintain lower cholesterol levels and can be expensive, even with insurance.
Statins have been shown to reduce heart attack and stroke in both genders.
Statins can lower LDL cholesterol by up to 50 percent. Lifestyle changes, at best, can lower LDL by up to 15 percent.
Muscle pain is reported in as many as seven percent of those who take statins but may ease with reduced dosage or another type of statin.
Statins for those w/o high cholesterol?
The Food and Drug Administration approved the new criteria last month for Crestor, which is made by AstraZeneca and is the nation’s second best-selling statin, behind Lipitor by Pfizer. AstraZeneca plans soon to begin a new marketing and advertising campaign for Crestor, based on the new F.D.A.-approved criteria.
Under those criteria, an estimated 6.5 million people in this country who have no cholesterol problems and no sign of heart problems will be deemed candidates for statins. That is in addition to the 80 million who already meet the current cholesterol-based guidelines — about half of whom now take statins.
The new Crestor label says it may be prescribed for apparently healthy people if they are older — men 50 and over and women 60 and over — and have one risk factor like smoking or high blood pressure, in addition to elevated inflammation in the body.
Statins decrease risk of clot-related diseases
Individuals at risk for heart attack and stroke may benefit from taking common cholesterol-lowering drugs known as statins, according to a study conducted by researchers at the University of Connecticut.
Statins may slow progression of multiple sclerosis
A UCSF-led study examining the impact of statins on the progression of multiple sclerosis found a lower incidence of new brain lesions in patients taking the cholesterol-lowering drug in the early stages of the disease as compared to a placebo.
Statins may lower the risk of certain cancers, including colorectal and skin cancers
Statins may benefit men with prostate cancer
Statin drugs may have a protective effect in the prevention of liver cancer
Statins Cut Risk of Cataracts and Dying
Statins, a class of drugs used to lower cholesterol levels, have been successfully fighting heart disease for years. A new study has now found that the same drugs cut the risks of cataracts in men by almost 40%. One recent study, featured as part of a Time magazine cover story, showed that statins can reduce a person's chance of dying from all combined diseases and conditions by 40%, something in the medical community called "all-cause mortality."
Statins fight gallstones
Use of the cholesterol-lowering drugs statins for more than a year is associated with a reduced risk of having gallstones requiring surgery, according to a study in the November 11 issue of JAMA.
Statins fight cancer, diabetes and Parkinson's?
Millions of people around the world use medicines based on statins to lower their blood cholesterol, but new research from the University of Gothenburg, published in the prestigious journal PNAS, shows that statins may also be effective in the treatment of cancer.
Statins lower cholesterol by blocking certain enzymes involved in our metabolism. However, they have also been shown to affect other important lipids in the body, such as the lipids that help proteins to attach to the cell membrane (known as lipid modification). Because many of the proteins that are lipid-modified cause cancer, there are now hopes that it will be possible to use statins in the treatment of cancer.
"Our results support the idea that statins can be used in more ways than just to lower cholesterol," says Pilon. "Not least that they can prevent the growth of cancer cells caused by lipid-modified proteins, but also that they can be effective in the treatment of diabetes and neurological disorders such as Parkinson's.
More Evidence Statins Fight Parkinson's
Simvastatin, a commonly used, cholesterol-lowering drug, may prevent Parkinson's disease from progressing further. Neurological researchers at Rush University Medical Center conducted a study examining the use of the FDA-approved medication in mice with Parkinson's disease and found that the drug successfully reverses the biochemical, cellular and anatomical changes caused by the disease.
According to the most recent health research reports, statins, including (I hope) red yeast rice, which I now take, fight cancer, diabetes and Parkinson's and, specifically, by lowering cholesterol, some types of prostate cancer. There's even more evidence statins fight Parkinson's. Statins also fight gallstones. Earlier reports showed many other benefits of statins.
Statins may lower the risk of certain cancers, including colorectal and skin cancers.
Statin Use Benefits Multiple Areas of Urologic Health
Several new studies presented at the American Urological Association's (AUA) 104th Annual Scientific Meeting suggest that the use of statins--commonly prescribed to lower cholesterol--may benefit men with prostate cancer, erectile dysfunction or lower urinary tract symptoms (LUTS). Several key research studies highlighting these benefits will be presented
Statins and Lung Fuction
Statins are known to be good for lowering cholesterol and maybe even fighting dementia, and now they have another reported benefit: they appear to slow decline in lung function in the elderly— even in those who smoke. According to researchers in Boston, it may be statins’ anti-inflammatory and antioxidant properties that help achieve this effect.
Statins can protect against Alzheimer's disease
High cholesterol levels are considered to be a risk factor not only for cardiovascular disease including stroke, but also for the development of Alzheimer's disease.
Statins Reduce Risk of Liver Cancer
Statin use is associated with a significant reduction in the risk of hepatocellular carcinoma (HCC), or liver cancer, among patients with diabetes, according to a new study in Gastroenterology.
Statins May Reduce Risk of Gallbladder Removal Surgery
The use of statins appears to reduce the risk of cholecystectomy, surgical removal of the gallbladder, in women, according to a new study in Gastroenterology.
Statins Help Protect Against Heart Attacks and Strokes In High Risk Population
High levels of high-sensitivity C-reactive protein (hs-CRP) leads to increased risk of cardiovascular disease. This risk decreases by up to 44% if the patients are treated with statin medications.
So I'm hoping he will prescribe one for me at my next appointment - and I will continue taking red yeast rice with co-enzyme Q-10 whiich should help avoid muscle problems.)
The evidence about all the good things statins do is overwhelming - as outlined below:
WHAT YOU SHOULD KNOW ABOUT STATINS
Statins must be taken regularly to maintain lower cholesterol levels and can be expensive, even with insurance.
Statins have been shown to reduce heart attack and stroke in both genders.
Statins can lower LDL cholesterol by up to 50 percent. Lifestyle changes, at best, can lower LDL by up to 15 percent.
Muscle pain is reported in as many as seven percent of those who take statins but may ease with reduced dosage or another type of statin.
Statins for those w/o high cholesterol?
The Food and Drug Administration approved the new criteria last month for Crestor, which is made by AstraZeneca and is the nation’s second best-selling statin, behind Lipitor by Pfizer. AstraZeneca plans soon to begin a new marketing and advertising campaign for Crestor, based on the new F.D.A.-approved criteria.
Under those criteria, an estimated 6.5 million people in this country who have no cholesterol problems and no sign of heart problems will be deemed candidates for statins. That is in addition to the 80 million who already meet the current cholesterol-based guidelines — about half of whom now take statins.
The new Crestor label says it may be prescribed for apparently healthy people if they are older — men 50 and over and women 60 and over — and have one risk factor like smoking or high blood pressure, in addition to elevated inflammation in the body.
Statins decrease risk of clot-related diseases
Individuals at risk for heart attack and stroke may benefit from taking common cholesterol-lowering drugs known as statins, according to a study conducted by researchers at the University of Connecticut.
Statins may slow progression of multiple sclerosis
A UCSF-led study examining the impact of statins on the progression of multiple sclerosis found a lower incidence of new brain lesions in patients taking the cholesterol-lowering drug in the early stages of the disease as compared to a placebo.
Statins may lower the risk of certain cancers, including colorectal and skin cancers
Statins may benefit men with prostate cancer
Statin drugs may have a protective effect in the prevention of liver cancer
Statins Cut Risk of Cataracts and Dying
Statins, a class of drugs used to lower cholesterol levels, have been successfully fighting heart disease for years. A new study has now found that the same drugs cut the risks of cataracts in men by almost 40%. One recent study, featured as part of a Time magazine cover story, showed that statins can reduce a person's chance of dying from all combined diseases and conditions by 40%, something in the medical community called "all-cause mortality."
Statins fight gallstones
Use of the cholesterol-lowering drugs statins for more than a year is associated with a reduced risk of having gallstones requiring surgery, according to a study in the November 11 issue of JAMA.
Statins fight cancer, diabetes and Parkinson's?
Millions of people around the world use medicines based on statins to lower their blood cholesterol, but new research from the University of Gothenburg, published in the prestigious journal PNAS, shows that statins may also be effective in the treatment of cancer.
Statins lower cholesterol by blocking certain enzymes involved in our metabolism. However, they have also been shown to affect other important lipids in the body, such as the lipids that help proteins to attach to the cell membrane (known as lipid modification). Because many of the proteins that are lipid-modified cause cancer, there are now hopes that it will be possible to use statins in the treatment of cancer.
"Our results support the idea that statins can be used in more ways than just to lower cholesterol," says Pilon. "Not least that they can prevent the growth of cancer cells caused by lipid-modified proteins, but also that they can be effective in the treatment of diabetes and neurological disorders such as Parkinson's.
More Evidence Statins Fight Parkinson's
Simvastatin, a commonly used, cholesterol-lowering drug, may prevent Parkinson's disease from progressing further. Neurological researchers at Rush University Medical Center conducted a study examining the use of the FDA-approved medication in mice with Parkinson's disease and found that the drug successfully reverses the biochemical, cellular and anatomical changes caused by the disease.
According to the most recent health research reports, statins, including (I hope) red yeast rice, which I now take, fight cancer, diabetes and Parkinson's and, specifically, by lowering cholesterol, some types of prostate cancer. There's even more evidence statins fight Parkinson's. Statins also fight gallstones. Earlier reports showed many other benefits of statins.
Statins may lower the risk of certain cancers, including colorectal and skin cancers.
Statin Use Benefits Multiple Areas of Urologic Health
Several new studies presented at the American Urological Association's (AUA) 104th Annual Scientific Meeting suggest that the use of statins--commonly prescribed to lower cholesterol--may benefit men with prostate cancer, erectile dysfunction or lower urinary tract symptoms (LUTS). Several key research studies highlighting these benefits will be presented
Statins and Lung Fuction
Statins are known to be good for lowering cholesterol and maybe even fighting dementia, and now they have another reported benefit: they appear to slow decline in lung function in the elderly— even in those who smoke. According to researchers in Boston, it may be statins’ anti-inflammatory and antioxidant properties that help achieve this effect.
Statins can protect against Alzheimer's disease
High cholesterol levels are considered to be a risk factor not only for cardiovascular disease including stroke, but also for the development of Alzheimer's disease.
Statins Reduce Risk of Liver Cancer
Statin use is associated with a significant reduction in the risk of hepatocellular carcinoma (HCC), or liver cancer, among patients with diabetes, according to a new study in Gastroenterology.
Statins May Reduce Risk of Gallbladder Removal Surgery
The use of statins appears to reduce the risk of cholecystectomy, surgical removal of the gallbladder, in women, according to a new study in Gastroenterology.
Statins Help Protect Against Heart Attacks and Strokes In High Risk Population
High levels of high-sensitivity C-reactive protein (hs-CRP) leads to increased risk of cardiovascular disease. This risk decreases by up to 44% if the patients are treated with statin medications.
Monday, May 24, 2010
Alcohol consumption may protect against Alzheimer's Disease
Ω
A new study published this month 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.
Researchers at the University of Valencia, the Generalitat Valenciana, and the Institut Municipal d'Investigació Mèdica, Barcelona, in Spain, carried out a study comparing personal and clinical antecedents of subjects affected with Alzheimer's disease with healthy people, both groups with the same age and gender distribution. Women included in the study were mainly light or moderate alcohol consumers. The risk of Alzheimer's disease was unaffected by any measure of tobacco consumption, but a protective effect of moderate alcohol consumption was observed, this effect being more evident in nonsmoker women.
"Our results suggest a protective effect of alcohol consumption, mostly in nonsmokers, and the need to consider interactions between tobacco and alcohol consumption, as well as interactions with gender, when assessing the effects of smoking and/or drinking on the risk of AD," according to lead investigator Ana M. Garcia, PhD, MPH, Department of Preventive Medicine and Public Health, University of Valencia. "Interactive effects of smoking and drinking are supported by the fact that both alcohol and tobacco affect brain neuronal receptors."
A new study published this month 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.
Researchers at the University of Valencia, the Generalitat Valenciana, and the Institut Municipal d'Investigació Mèdica, Barcelona, in Spain, carried out a study comparing personal and clinical antecedents of subjects affected with Alzheimer's disease with healthy people, both groups with the same age and gender distribution. Women included in the study were mainly light or moderate alcohol consumers. The risk of Alzheimer's disease was unaffected by any measure of tobacco consumption, but a protective effect of moderate alcohol consumption was observed, this effect being more evident in nonsmoker women.
"Our results suggest a protective effect of alcohol consumption, mostly in nonsmokers, and the need to consider interactions between tobacco and alcohol consumption, as well as interactions with gender, when assessing the effects of smoking and/or drinking on the risk of AD," according to lead investigator Ana M. Garcia, PhD, MPH, Department of Preventive Medicine and Public Health, University of Valencia. "Interactive effects of smoking and drinking are supported by the fact that both alcohol and tobacco affect brain neuronal receptors."
Getting Back To Nature Can Make You Smarter And Happier
Ω
Can bacteria make you smarter?
Exposure to specific bacteria in the environment, already believed to have antidepressant qualities, could increase learning behavior according to research presented at the 110th General Meeting of the American Society for Microbiology in San Diego.
"Mycobacterium vaccae is a natural soil bacterium which people likely ingest or breath in when they spend time in nature," says Dorothy Matthews of The Sage Colleges in Troy, New York, who conducted the research with her colleague Susan Jenks.
Previous research studies on M. vaccae showed that heat-killed bacteria injected into mice stimulated growth of some neurons in the brain that resulted in increased levels of serotonin and decreased anxiety.
"Since serotonin plays a role in learning we wondered if live M. vaccae could improve learning in mice," says Matthews.
Matthews and Jenks fed live bacteria to mice and assessed their ability to navigate a maze compared to control mice that were not fed the bacteria.
"We found that mice that were fed live M. vaccae navigated the maze twice as fast and with less demonstrated anxiety behaviors as control mice," says Matthews.
In a second experiment the bacteria were removed from the diet of the experimental mice and they were retested. While the mice ran the maze slower than they did when they were ingesting the bacteria, on average they were still faster than the controls.
A final test was given to the mice after three weeks' rest. While the experimental mice continued to navigate the maze faster than the controls, the results were no longer statistically significant, suggesting the effect is temporary.
"This research suggests that M. vaccae may play a role in anxiety and learning in mammals," says Matthews. "It is interesting to speculate that creating learning environments in schools that include time in the outdoors where M. vaccae is present may decrease anxiety and improve the ability to learn new tasks."
Can bacteria make you smarter?
Exposure to specific bacteria in the environment, already believed to have antidepressant qualities, could increase learning behavior according to research presented at the 110th General Meeting of the American Society for Microbiology in San Diego.
"Mycobacterium vaccae is a natural soil bacterium which people likely ingest or breath in when they spend time in nature," says Dorothy Matthews of The Sage Colleges in Troy, New York, who conducted the research with her colleague Susan Jenks.
Previous research studies on M. vaccae showed that heat-killed bacteria injected into mice stimulated growth of some neurons in the brain that resulted in increased levels of serotonin and decreased anxiety.
"Since serotonin plays a role in learning we wondered if live M. vaccae could improve learning in mice," says Matthews.
Matthews and Jenks fed live bacteria to mice and assessed their ability to navigate a maze compared to control mice that were not fed the bacteria.
"We found that mice that were fed live M. vaccae navigated the maze twice as fast and with less demonstrated anxiety behaviors as control mice," says Matthews.
In a second experiment the bacteria were removed from the diet of the experimental mice and they were retested. While the mice ran the maze slower than they did when they were ingesting the bacteria, on average they were still faster than the controls.
A final test was given to the mice after three weeks' rest. While the experimental mice continued to navigate the maze faster than the controls, the results were no longer statistically significant, suggesting the effect is temporary.
"This research suggests that M. vaccae may play a role in anxiety and learning in mammals," says Matthews. "It is interesting to speculate that creating learning environments in schools that include time in the outdoors where M. vaccae is present may decrease anxiety and improve the ability to learn new tasks."
Anti-aging supplements may be best taken not too late in life
Ω
Anti-aging supplements made up of mixtures might be better than single compounds at preventing decline in physical function, according to researchers at the University of Florida's Institute on Aging. In addition, it appears that such so-called neutraceuticals should be taken before very old age for benefits such as improvement in physical function.
The findings from rat studies, published last week in the journal PLoS One, have implications for how dietary supplementation can be used effectively in humans.
"I think it is important for people to focus on good nutrition, but for those of advanced age who are running out of energy and not moving much, we're trying to find a supplement mixture that can help improve their quality of life," said Christiaan Leeuwenburgh, Ph.D., senior author of the paper and chief of the biology of aging division in the UF College of Medicine.
Scientists do not fully understand all the processes that lead to loss of function as people age. But more and more research points to the mitochondrial free radical theory of aging, that as people age, oxidative damage piles up in individual cells such that the energy-generation system inside some cells stops working properly.
To address that problem, many anti-aging studies and supplements are geared toward reducing the effects of free radicals.
The UF researchers investigated the potential anti-aging benefits of a commercially available mixture marketed for relieving chronic fatigue and protecting against muscle aging. The supplement contains the antioxidant coenzyme Q10, creatine — a compound that aids muscle performance — and ginseng, which also has been shown to have antioxidant properties.
The study gauged the effects of the mixture on physical performance as well as on two mechanisms that underlie the aging process and many age-related disorders: dysfunction of the cells' energy producing powerhouses, known as mitochondria, and oxidative stress.
The researchers fed the supplement to middle-aged 21-month-old and late-middle-aged 29-month-old rats — corresponding to 50- to 65-year-old and 65- to 80-year-old humans, respectively — for six weeks, and measured how strongly their paws could grip. Grip strength in rats is analogous to physical performance in humans, and deterioration in grip strength can provide useful information about muscle weakness or loss seen in older adults.
Grip strength improved 12 percent in the middle-aged rats compared with controls, but no improvement was found in the older group.
Measurements of the function of mitochondria corresponded with the grip strength findings. Stress tests showed that mitochondrial function improved 66 percent compared with controls in middle-aged rats but not in the older ones. That suggests that supplementation might be of greater effect before major age-related functional and other declines have set in, the researchers said.
"It is possible that there is a window during which these compounds will work, and if the intervention is given after that time it won't work," said Jinze Xu, Ph.D., first author of the paper and a postdoctoral researcher at UF.
The researchers are working to identify the optimal age at which various interventions can enhance behavioral or physical performance. Very few studies have been done to show the effect of interventions on the very old.
Interestingly, although the older rats had no improvement in physical performance or mitochondrial function, they had lowered levels of oxidative damage.
That shows that reduction of oxidative stress damage is not always matched by functional changes such as improvement in muscle strength.
As a result, research must focus on compounds that promote proper functioning of the mitochondria, since mitochondrial health is essential in older animals for reducing oxidative stress, the researchers said. And clinical trials need to be performed to test the effectiveness of the supplements in humans.
"It's going to be very important to focus less on oxidative stress and biomarkers, and focus on having sufficient energy," Leeuwenburgh said. "If energy declines, then you have an increased chance for oxidative stress or failure of repair mechanisms that recognize oxidative damage — we're seeing that the health of mitochondria is central to aging."
It is possible that although the supplement could help reduce the oxidative stress damage, because damage in much older animals was too great, energy could not be restored.
The different compounds in the mixture acted to produce effects that single compounds did not, because each component affected a different biochemical pathway in the body, addressing both oxidative stress and mitochondrial function, researchers said.
"People are catching on that using a single compound is not a good strategy — you have to use multiple compounds and target one or multiple pathways," Leeuwenburgh said.
Anti-aging supplements made up of mixtures might be better than single compounds at preventing decline in physical function, according to researchers at the University of Florida's Institute on Aging. In addition, it appears that such so-called neutraceuticals should be taken before very old age for benefits such as improvement in physical function.
The findings from rat studies, published last week in the journal PLoS One, have implications for how dietary supplementation can be used effectively in humans.
"I think it is important for people to focus on good nutrition, but for those of advanced age who are running out of energy and not moving much, we're trying to find a supplement mixture that can help improve their quality of life," said Christiaan Leeuwenburgh, Ph.D., senior author of the paper and chief of the biology of aging division in the UF College of Medicine.
Scientists do not fully understand all the processes that lead to loss of function as people age. But more and more research points to the mitochondrial free radical theory of aging, that as people age, oxidative damage piles up in individual cells such that the energy-generation system inside some cells stops working properly.
To address that problem, many anti-aging studies and supplements are geared toward reducing the effects of free radicals.
The UF researchers investigated the potential anti-aging benefits of a commercially available mixture marketed for relieving chronic fatigue and protecting against muscle aging. The supplement contains the antioxidant coenzyme Q10, creatine — a compound that aids muscle performance — and ginseng, which also has been shown to have antioxidant properties.
The study gauged the effects of the mixture on physical performance as well as on two mechanisms that underlie the aging process and many age-related disorders: dysfunction of the cells' energy producing powerhouses, known as mitochondria, and oxidative stress.
The researchers fed the supplement to middle-aged 21-month-old and late-middle-aged 29-month-old rats — corresponding to 50- to 65-year-old and 65- to 80-year-old humans, respectively — for six weeks, and measured how strongly their paws could grip. Grip strength in rats is analogous to physical performance in humans, and deterioration in grip strength can provide useful information about muscle weakness or loss seen in older adults.
Grip strength improved 12 percent in the middle-aged rats compared with controls, but no improvement was found in the older group.
Measurements of the function of mitochondria corresponded with the grip strength findings. Stress tests showed that mitochondrial function improved 66 percent compared with controls in middle-aged rats but not in the older ones. That suggests that supplementation might be of greater effect before major age-related functional and other declines have set in, the researchers said.
"It is possible that there is a window during which these compounds will work, and if the intervention is given after that time it won't work," said Jinze Xu, Ph.D., first author of the paper and a postdoctoral researcher at UF.
The researchers are working to identify the optimal age at which various interventions can enhance behavioral or physical performance. Very few studies have been done to show the effect of interventions on the very old.
Interestingly, although the older rats had no improvement in physical performance or mitochondrial function, they had lowered levels of oxidative damage.
That shows that reduction of oxidative stress damage is not always matched by functional changes such as improvement in muscle strength.
As a result, research must focus on compounds that promote proper functioning of the mitochondria, since mitochondrial health is essential in older animals for reducing oxidative stress, the researchers said. And clinical trials need to be performed to test the effectiveness of the supplements in humans.
"It's going to be very important to focus less on oxidative stress and biomarkers, and focus on having sufficient energy," Leeuwenburgh said. "If energy declines, then you have an increased chance for oxidative stress or failure of repair mechanisms that recognize oxidative damage — we're seeing that the health of mitochondria is central to aging."
It is possible that although the supplement could help reduce the oxidative stress damage, because damage in much older animals was too great, energy could not be restored.
The different compounds in the mixture acted to produce effects that single compounds did not, because each component affected a different biochemical pathway in the body, addressing both oxidative stress and mitochondrial function, researchers said.
"People are catching on that using a single compound is not a good strategy — you have to use multiple compounds and target one or multiple pathways," Leeuwenburgh said.
Multivitamins Produce Positive Results
Ω
The effects of multivitamins are most often researched in the elderly. This is one of very few studies to assess the relationship between supplementation with vitamins/minerals and psychological functioning in healthy groups of non-elderly adults. This study shows how a proprietary multivitamin and mineral supplement improves mood and mental performance while also reducing stress, mental tiredness and fatigue in healthy males.
Research into a vitamin and mineral supplement by academics at Northumbria University shows it improves mood and mental performance while also reducing stress, mental tiredness and fatigue in healthy males.
In a randomized, double-blind and placebo-controlled study, 215 men in full-time employment aged between 30 and 55 were given either a proprietary multivitamin or a placebo for a period of 33 days.
The two groups were tested at the beginning of the study and at the end with a battery of mood, stress and health questionnaires and with physical and mental tasks that included mental arithmetic (counting backwards in 3s or 7s from a random number).
The multivitamin was a B complex, vitamin C and minerals product known as Berocca® which is manufactured by Bayer Consumer Care, the sponsors of the study.
Prior to treatment, there were no significant differences between the placebo and multi-vitamin/minerals groups in performance or ratings for any of the study outcomes. However, after 33 days supplementation the multivitamin/minerals group reported significantly improved ratings of general mental health, reduced subjective stress and increased ratings of 'vigour', with a strong trend towards an overall improvement in mood. Task performance, in terms of the number of correct serial-3 subtractions throughout the six repetitions of the cognitive tasks, and serial-7s during the first repetition, was also improved. This was accompanied by reduced ratings of 'mental tiredness' before and after the intense mental processing and a trend towards reduced 'mental fatigue'. The placebo group showed no significant changes.
The effects of multivitamins are most often researched in the elderly, and very few studies have assessed the relationship between supplementation with vitamins/minerals and psychological functioning in healthy groups of non-elderly adults.
"Overall, these results suggest that improving nutritional status, by supplementation if necessary, may be beneficial to males within the general population as a whole," says Northumbria University's Professor David Kennedy, who led the study.
"The assumption was made here that the men tested enjoyed typical nutritional status. However, the very fact of being able to improve mood, ratings of mental health and vigour and aspects of task performance by simple supplementation with B vitamins, Vitamin C and minerals indicates that the cohort must have been suffering from less than optimal micronutrient status at the outset."
"We know that optimum functioning of the central nervous system is dependent on a wide range of micronutrients, and there is a wealth of evidence from epidemiological studies that clearly suggest a relationship between micro-nutrients and psychological functioning.
"Vitamin C for example is the brain's most prevalent antioxidant and is found at its greatest concentrations in neuron-rich areas."
The effects of multivitamins are most often researched in the elderly. This is one of very few studies to assess the relationship between supplementation with vitamins/minerals and psychological functioning in healthy groups of non-elderly adults. This study shows how a proprietary multivitamin and mineral supplement improves mood and mental performance while also reducing stress, mental tiredness and fatigue in healthy males.
Research into a vitamin and mineral supplement by academics at Northumbria University shows it improves mood and mental performance while also reducing stress, mental tiredness and fatigue in healthy males.
In a randomized, double-blind and placebo-controlled study, 215 men in full-time employment aged between 30 and 55 were given either a proprietary multivitamin or a placebo for a period of 33 days.
The two groups were tested at the beginning of the study and at the end with a battery of mood, stress and health questionnaires and with physical and mental tasks that included mental arithmetic (counting backwards in 3s or 7s from a random number).
The multivitamin was a B complex, vitamin C and minerals product known as Berocca® which is manufactured by Bayer Consumer Care, the sponsors of the study.
Prior to treatment, there were no significant differences between the placebo and multi-vitamin/minerals groups in performance or ratings for any of the study outcomes. However, after 33 days supplementation the multivitamin/minerals group reported significantly improved ratings of general mental health, reduced subjective stress and increased ratings of 'vigour', with a strong trend towards an overall improvement in mood. Task performance, in terms of the number of correct serial-3 subtractions throughout the six repetitions of the cognitive tasks, and serial-7s during the first repetition, was also improved. This was accompanied by reduced ratings of 'mental tiredness' before and after the intense mental processing and a trend towards reduced 'mental fatigue'. The placebo group showed no significant changes.
The effects of multivitamins are most often researched in the elderly, and very few studies have assessed the relationship between supplementation with vitamins/minerals and psychological functioning in healthy groups of non-elderly adults.
"Overall, these results suggest that improving nutritional status, by supplementation if necessary, may be beneficial to males within the general population as a whole," says Northumbria University's Professor David Kennedy, who led the study.
"The assumption was made here that the men tested enjoyed typical nutritional status. However, the very fact of being able to improve mood, ratings of mental health and vigour and aspects of task performance by simple supplementation with B vitamins, Vitamin C and minerals indicates that the cohort must have been suffering from less than optimal micronutrient status at the outset."
"We know that optimum functioning of the central nervous system is dependent on a wide range of micronutrients, and there is a wealth of evidence from epidemiological studies that clearly suggest a relationship between micro-nutrients and psychological functioning.
"Vitamin C for example is the brain's most prevalent antioxidant and is found at its greatest concentrations in neuron-rich areas."
Aspirin = 5 Times Risk of Crohn's Disease
Crohn's disease is a serious condition affecting 60,000 people in the UK and 500,000 people in the US. It is characterized by inflammation and swelling of any part of the digestive system. This can lead to debilitating symptoms and requires patients to take life-long medication. Some patients need surgery and some sufferers have an increased risk of bowel cancer.
Though there are likely to be many causes of the disease, previous work on tissue samples has shown that aspirin can have a harmful effect on the bowel. To investigate this potential link further, the UEA team followed 200,000 volunteers aged 30-74 in the UK, Sweden, Denmark, Germany and Italy. The volunteers had been recruited for the EPIC study (European Prospective Investigation into Cancer and Nutrition) between 1993 and 1997.
The volunteers were all initially well, but by 2004 a small number had developed Crohn's disease. When looking for differences in aspirin use between those who did and did not develop the disease, the researchers discovered that those taking aspirin regularly for a year or more were around five times more likely to develop Crohn's disease.
The study also showed that aspirin use had no effect on the risk of developing ulcerative colitis -- a condition similar to Crohn's disease.
"This is early work but our findings do suggest that the regular use of aspirin could be one of many factors which influences the development of this distressing disease in some patients," said Dr Hart.
"Aspirin does have many beneficial effects, however, including helping to prevent heart attacks and strokes. I would urge aspirin users to continue taking this medication since the risk of aspirin users possibly developing Crohn's disease remains very low -- only one in every 2000 users, and the link is not yet finally proved."
Further work must now be done in other populations to establish whether there is a definite link and to check that aspirin use is not just a marker of another risk factor which is the real cause of Crohn's disease. The UEA team will also continue its wider research into other potential factors in the development of Crohn's disease, including diet.
Though there are likely to be many causes of the disease, previous work on tissue samples has shown that aspirin can have a harmful effect on the bowel. To investigate this potential link further, the UEA team followed 200,000 volunteers aged 30-74 in the UK, Sweden, Denmark, Germany and Italy. The volunteers had been recruited for the EPIC study (European Prospective Investigation into Cancer and Nutrition) between 1993 and 1997.
The volunteers were all initially well, but by 2004 a small number had developed Crohn's disease. When looking for differences in aspirin use between those who did and did not develop the disease, the researchers discovered that those taking aspirin regularly for a year or more were around five times more likely to develop Crohn's disease.
The study also showed that aspirin use had no effect on the risk of developing ulcerative colitis -- a condition similar to Crohn's disease.
"This is early work but our findings do suggest that the regular use of aspirin could be one of many factors which influences the development of this distressing disease in some patients," said Dr Hart.
"Aspirin does have many beneficial effects, however, including helping to prevent heart attacks and strokes. I would urge aspirin users to continue taking this medication since the risk of aspirin users possibly developing Crohn's disease remains very low -- only one in every 2000 users, and the link is not yet finally proved."
Further work must now be done in other populations to establish whether there is a definite link and to check that aspirin use is not just a marker of another risk factor which is the real cause of Crohn's disease. The UEA team will also continue its wider research into other potential factors in the development of Crohn's disease, including diet.
Folic Acid Revisited
A reader of my health tips inquired about Folic Acid last week. I went through my archives for him and sent him this:
TUESDAY, NOVEMBER 17, 2009
Folic Acid = Increased Risk of Cancer, Death
Patients with heart disease in Norway, a country with no fortification of foods with folic acid, had an associated increased risk of cancer and death from any cause if they had received treatment with folic acid and vitamin B12, according to a study in the November 18 issue of JAMA.
Posted by Jonathan Kantrowitz at 2:19 PM 0 comments
Health Benefits, Consequences of Folic Acid Dependent on Circumstances
For the past several decades, evidence has shown that greater dietary intake of the B-vitamin, folate, offers protection against the development of certain common cancers and reduces neural tube defects in newborns, opening new avenues for public health interventions that have a great impact on health. However, folate’s central role as an essential factor in DNA synthesis also means that abundant availability of the vitamin can enhance the development of pre-cancerous and cancerous tumors. Further, the intake of folic acid that results from consuming foods that are voluntarily fortified (e.g.: ready-to-eat cereals) in combination with the additional intake received from mandatory fortification of flour means that supplementary intake of folic acid is unnecessary for many segments of the population, and may even present a risk. Nevertheless, the issue is a complicated one since women of child-bearing age seem to benefit from supplemental folic acid in regard to its protection against birth defects. In the April issue of the journal Nutrition Reviews, two new articles by Omar Dary, Ph.D., and Joel B. Mason, M.D., assess the conditions under which folic acid can be beneficial and harmful and contribute to guidelines for the healthful intake of folic acid as a complement to dietary folate.
The consequences of inadequate folate intake remain prevalent in many countries, even in industrial countries where specific interventions of folic acid have not been implemented. Moreover, there continues to be some concern—which, to date, lacks compelling scientific evidence—that the synthetic form of the vitamin, folic acid, might have adverse effects that do not exist with natural sources of folate.
Under most circumstances, adequate intake of folate appears to assume the role of a protective agent against cancer, most notably colorectal cancer. However, in select circumstances in which an individual who harbors a pre-cancerous or cancerous tumor consumes too much folic acid, the additional amounts of folate may instead facilitate the promotion of cancer. In countries in which the fortification of flour with folic acid is working well, additional supplementation in the form of vitamin pills can lead to excessive intakes of the vitamin, which can then have undesirable adverse effects.
Thus, folate appears to assume different guises depending on the circumstances. The level of intake of this micronutrient that is safe for one person may be potentially harmful to another.
“These effects of folate on the risk of developing cancer have created a global dilemma in the efforts to institute nationwide folic acid fortification programs around the world,” Mason notes.
Most individuals in the U.S. population are now folate-replete, so one consideration would be to reduce the doses of the vitamin that are present in most over-the-counter supplements. Many people receive sufficient amounts of folate through their diet.
Now that the supply of folic acid in the diet is much larger than it was prior to mandatory fortification, food policies may need to be adjusted to the current knowledge and the new circumstances.
“The design of cogent public health policies that effectively optimize health for many while presenting no or minimal risk to others, must often occur in the absence of complete information,” Mason concludes. “However, we are nevertheless obliged to deliberate with as much of an in-depth understanding as the existing science allows.”
Folic Acid Fortification May Be Linked to Increased Colon Cancer Risk
The rate of colorectal cancer in Chile may have increased since that country began fortifying wheat flour with folic acid, reports a study in the European Journal of Gastroenterology & Hepatology. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health, a leading provider of information and business intelligence for students, professionals, and institutions in medicine, nursing, allied health, pharmacy and the pharmaceutical industry.
"Our data provide new evidence that a folate fortification program could be associated with an additional risk of colon cancer," according to the new report by Dr. Sandra Hirsch and colleagues of University of Chile, Santiago.
Possible Increase in Colon Cancer after Start of Folic Acid Fortification
The researchers analyzed changes in colon cancer rates since the Chilean government introduced a mandatory program of folic acid fortification of wheat flour in 2000. Several countries have implemented similar policies in recent years, with the goal of preventing spina bifida and other neural tube defects. In Chile, the rate of neural tube defects decreased by 40 percent in the first year after the start of folic acid fortification. __The researchers compared hospital discharge data on colon cancer rates in Chile in four-year periods before and after folic acid fortification: 1992-96 versus 2001-04. Although no causative relationship can be proven, the data suggested a significant "temporal relationship" between folic acid supplementation and colorectal cancer. Reported cases of colon cancer increased by 162 percent in people aged 45 to 64 and by 190 percent in people aged 65 to 79.
After adjustment for other factors, discharge diagnoses of colon cancer in these age groups were two to three times more frequent after the start of folic acid fortification. Most other diseases showed no consistent pattern of changes. There was a small increase in breast cancer, which may have been related to early detection and universal treatment programs for breast cancer.
Evidence Is Weaker than Similar Changes Reported in U.S. and Canada
Chile is the third country to report an apparent increase in colorectal cancer after introducing a national folic acid fortification program. A 2007 paper suggested increases in colorectal cancer after folic acid fortification was introduced in the United States and Canada in the mid-1990s. Chile uses a higher "dose" of folic acid than the two North American countries. Folic acid fortification has not yet been introduced in Europe.
There are other possible explanations for the rise in colon cancer in Chile, including increases in obesity and other risk factors.
Another important limitation of the study was the use of hospital discharge data to identify cases of colon cancer. "Discharge rates are influenced by health care politics, increasing access to healthcare for new strata of the population with increased cancer risk, and so forth," comments Dr. Reinhold Stockbrugger, one of the editors of The European Journal of Gastroenterology & Hepatology. "This study provides only a weak, indirect indication of a causal relationship between folate enrichment and colorectal cancer, though similar to that reported in the U.S. and Canada."
Folic Acid Supplements Linked To Higher Risk Of Prostate Cancer
A study led by researchers at the University of Southern California (USC) found that men who took a daily folic acid supplement of 1 mg daily had more than twice the risk of prostate cancer compared with men who took a placebo.
The finding came from a secondary analysis of the Aspirin/Folate Polyp Prevention Study (AFPP), a placebo-controlled randomized trial to determine the impact of aspirin and folic acid on colon polyps in men and women who were at high risk for the disease. The results appear in the March 10 online issue of the Journal of the National Cancer Institute.
Folic acid (folate) is a B vitamin found in many vegetables, beans, fruits and whole grains. While evidence of its ability to reduce neural tube defects in infants while taken by the mother before or during pregnancy has been well documented, its effects on other conditions are unclear.
“We know that adequate folate levels are important in the prevention of several cancer types, cardiovascular and neurological diseases,” says lead author Jane Figueiredo, Ph.D., assistant professor of preventive medicine at the Keck School of Medicine of USC. “However, little has been known about its role in prostate cancer. Our objective was to investigate the relationship between folic acid supplements and dietary folate and risk of prostate cancer.”
The AFPP study was conducted between 1994 and 2006 and found that aspirin reduced the risk of colon polyps while folic acid had a negative effect and increased the risk of advanced and multiple polyps. The first analysis did not address the impact of folic acid supplements on prostate cancer risk. Previous observational studies have been inconsistent. Some studies suggest that increased folate in the diet or in supplements might actually lower the risk of prostate cancer, and others have suggested no effect or even a potential harmful effect.
In the secondary analysis, researchers looked at prostate cancer incidence among 643 men who were randomly assigned to 1 mg daily folic acid supplements or placebo in the AFPP study and who enrolled in an extended follow-up study. The estimated prostate cancer risk was 9.7 percent at 10 years in men assigned to folate, compared with 3.3 percent in men assigned to placebo.
By contrast, dietary folate intake and plasma folate showed a trend toward reduced risk of prostate cancer, although the difference did not reach statistical significance. It remains unclear why dietary and circulating folate among non-multivitamin users may be inversely associated with risk, Figueiredo says.
“The synthetic form of folate, folic acid, found in supplements, is more bioavailable compared to folate from dietary sources and we know the amount of folate available is critical,” she says. “Adequate levels of folate may be beneficial, but too much folate is unlikely to be beneficial.”
Alternatively, these results may be due to chance, and replication by other studies is needed, she notes.
“These findings highlight the potentially complex role of folate in prostate cancer. The possibility of different effects from folic acid-containing supplements versus natural sources of folate definitely merits further investigation.”
Folic Acid Linked to Increased Cancer Rate
Two recent commentaries appearing in the November issue of Nutrition Reviews find that the introduction of flour fortified with folic acid into common foods was followed by an increase in colon cancer diagnoses in the U.S. and Canada. The two new review articles address these recent findings and provide an overview of the existing evidence on folic acid fortification and the associated policy issues.
For nearly a decade, folic acid, a chemical form of a common B vitamin (folate), has been added to wheat flour and other grain products in the U.S. and Canada. This public health measure was enacted after evidence was discovered linking folic acid with a reduced rate of a specific birth defect that affected the development of the spinal cord and central nervous system. During the same period, however, rates of colorectal cancer in the U.S. inexplicably began rising, even as regular colonoscopy check-ups became more common. In Canada, where folic acid supplementation was introduced a bit later, the same trend has been observed.
Dr. Solomons, author of one of the review commentaries, “Food Fortification with Folic Acid: Has the Other Shoe Dropped?” advises that a careful reconsideration of the fortification program is needed. “One size of dietary folic acid exposure does not fit all. It can be beneficial to some and detrimental to others at the same time,” comments Solomons.
Since the risk-benefit value of fortification varies according to age, Solomons suggests a reevaluation of the manner in which folic acid to prevent birth defects is delivered to the public. Among other things, targeting women of reproductive age while reducing folic acid levels in foods for which fortification is optional (such as ready-to-eat cereals and commercial drinks), would be worthy of consideration, in the opinion of Solomons.
As a result of noted birth defect reduction, 42 countries have implemented some form of mandatory folic acid fortification. The two commentaries stress the need to carefully consider and balance the risks and benefits associated with introducing such a program.
“Folic acid supplementation wields a double-edged sword,” remarks Dr. Young-In Kim, author of “Folic Acid Fortification and Supplementation—Good for Some but Not So Good for Others,” the other commentary review published in the November issue. According to Kim, “It may be beneficial or harmful, depending on the timing of intervention.” Exposure to high intakes of folic acid in early life and young adulthood may provide life-long protection from the tendency for cancer formation in different organs, such as the large intestines, whereas such exposures later in life, when cell damage has occurred, can spur on the advance of the tumor.
TUESDAY, NOVEMBER 17, 2009
Folic Acid = Increased Risk of Cancer, Death
Patients with heart disease in Norway, a country with no fortification of foods with folic acid, had an associated increased risk of cancer and death from any cause if they had received treatment with folic acid and vitamin B12, according to a study in the November 18 issue of JAMA.
Posted by Jonathan Kantrowitz at 2:19 PM 0 comments
Health Benefits, Consequences of Folic Acid Dependent on Circumstances
For the past several decades, evidence has shown that greater dietary intake of the B-vitamin, folate, offers protection against the development of certain common cancers and reduces neural tube defects in newborns, opening new avenues for public health interventions that have a great impact on health. However, folate’s central role as an essential factor in DNA synthesis also means that abundant availability of the vitamin can enhance the development of pre-cancerous and cancerous tumors. Further, the intake of folic acid that results from consuming foods that are voluntarily fortified (e.g.: ready-to-eat cereals) in combination with the additional intake received from mandatory fortification of flour means that supplementary intake of folic acid is unnecessary for many segments of the population, and may even present a risk. Nevertheless, the issue is a complicated one since women of child-bearing age seem to benefit from supplemental folic acid in regard to its protection against birth defects. In the April issue of the journal Nutrition Reviews, two new articles by Omar Dary, Ph.D., and Joel B. Mason, M.D., assess the conditions under which folic acid can be beneficial and harmful and contribute to guidelines for the healthful intake of folic acid as a complement to dietary folate.
The consequences of inadequate folate intake remain prevalent in many countries, even in industrial countries where specific interventions of folic acid have not been implemented. Moreover, there continues to be some concern—which, to date, lacks compelling scientific evidence—that the synthetic form of the vitamin, folic acid, might have adverse effects that do not exist with natural sources of folate.
Under most circumstances, adequate intake of folate appears to assume the role of a protective agent against cancer, most notably colorectal cancer. However, in select circumstances in which an individual who harbors a pre-cancerous or cancerous tumor consumes too much folic acid, the additional amounts of folate may instead facilitate the promotion of cancer. In countries in which the fortification of flour with folic acid is working well, additional supplementation in the form of vitamin pills can lead to excessive intakes of the vitamin, which can then have undesirable adverse effects.
Thus, folate appears to assume different guises depending on the circumstances. The level of intake of this micronutrient that is safe for one person may be potentially harmful to another.
“These effects of folate on the risk of developing cancer have created a global dilemma in the efforts to institute nationwide folic acid fortification programs around the world,” Mason notes.
Most individuals in the U.S. population are now folate-replete, so one consideration would be to reduce the doses of the vitamin that are present in most over-the-counter supplements. Many people receive sufficient amounts of folate through their diet.
Now that the supply of folic acid in the diet is much larger than it was prior to mandatory fortification, food policies may need to be adjusted to the current knowledge and the new circumstances.
“The design of cogent public health policies that effectively optimize health for many while presenting no or minimal risk to others, must often occur in the absence of complete information,” Mason concludes. “However, we are nevertheless obliged to deliberate with as much of an in-depth understanding as the existing science allows.”
Folic Acid Fortification May Be Linked to Increased Colon Cancer Risk
The rate of colorectal cancer in Chile may have increased since that country began fortifying wheat flour with folic acid, reports a study in the European Journal of Gastroenterology & Hepatology. The journal is published by Lippincott Williams & Wilkins, a part of Wolters Kluwer Health, a leading provider of information and business intelligence for students, professionals, and institutions in medicine, nursing, allied health, pharmacy and the pharmaceutical industry.
"Our data provide new evidence that a folate fortification program could be associated with an additional risk of colon cancer," according to the new report by Dr. Sandra Hirsch and colleagues of University of Chile, Santiago.
Possible Increase in Colon Cancer after Start of Folic Acid Fortification
The researchers analyzed changes in colon cancer rates since the Chilean government introduced a mandatory program of folic acid fortification of wheat flour in 2000. Several countries have implemented similar policies in recent years, with the goal of preventing spina bifida and other neural tube defects. In Chile, the rate of neural tube defects decreased by 40 percent in the first year after the start of folic acid fortification. __The researchers compared hospital discharge data on colon cancer rates in Chile in four-year periods before and after folic acid fortification: 1992-96 versus 2001-04. Although no causative relationship can be proven, the data suggested a significant "temporal relationship" between folic acid supplementation and colorectal cancer. Reported cases of colon cancer increased by 162 percent in people aged 45 to 64 and by 190 percent in people aged 65 to 79.
After adjustment for other factors, discharge diagnoses of colon cancer in these age groups were two to three times more frequent after the start of folic acid fortification. Most other diseases showed no consistent pattern of changes. There was a small increase in breast cancer, which may have been related to early detection and universal treatment programs for breast cancer.
Evidence Is Weaker than Similar Changes Reported in U.S. and Canada
Chile is the third country to report an apparent increase in colorectal cancer after introducing a national folic acid fortification program. A 2007 paper suggested increases in colorectal cancer after folic acid fortification was introduced in the United States and Canada in the mid-1990s. Chile uses a higher "dose" of folic acid than the two North American countries. Folic acid fortification has not yet been introduced in Europe.
There are other possible explanations for the rise in colon cancer in Chile, including increases in obesity and other risk factors.
Another important limitation of the study was the use of hospital discharge data to identify cases of colon cancer. "Discharge rates are influenced by health care politics, increasing access to healthcare for new strata of the population with increased cancer risk, and so forth," comments Dr. Reinhold Stockbrugger, one of the editors of The European Journal of Gastroenterology & Hepatology. "This study provides only a weak, indirect indication of a causal relationship between folate enrichment and colorectal cancer, though similar to that reported in the U.S. and Canada."
Folic Acid Supplements Linked To Higher Risk Of Prostate Cancer
A study led by researchers at the University of Southern California (USC) found that men who took a daily folic acid supplement of 1 mg daily had more than twice the risk of prostate cancer compared with men who took a placebo.
The finding came from a secondary analysis of the Aspirin/Folate Polyp Prevention Study (AFPP), a placebo-controlled randomized trial to determine the impact of aspirin and folic acid on colon polyps in men and women who were at high risk for the disease. The results appear in the March 10 online issue of the Journal of the National Cancer Institute.
Folic acid (folate) is a B vitamin found in many vegetables, beans, fruits and whole grains. While evidence of its ability to reduce neural tube defects in infants while taken by the mother before or during pregnancy has been well documented, its effects on other conditions are unclear.
“We know that adequate folate levels are important in the prevention of several cancer types, cardiovascular and neurological diseases,” says lead author Jane Figueiredo, Ph.D., assistant professor of preventive medicine at the Keck School of Medicine of USC. “However, little has been known about its role in prostate cancer. Our objective was to investigate the relationship between folic acid supplements and dietary folate and risk of prostate cancer.”
The AFPP study was conducted between 1994 and 2006 and found that aspirin reduced the risk of colon polyps while folic acid had a negative effect and increased the risk of advanced and multiple polyps. The first analysis did not address the impact of folic acid supplements on prostate cancer risk. Previous observational studies have been inconsistent. Some studies suggest that increased folate in the diet or in supplements might actually lower the risk of prostate cancer, and others have suggested no effect or even a potential harmful effect.
In the secondary analysis, researchers looked at prostate cancer incidence among 643 men who were randomly assigned to 1 mg daily folic acid supplements or placebo in the AFPP study and who enrolled in an extended follow-up study. The estimated prostate cancer risk was 9.7 percent at 10 years in men assigned to folate, compared with 3.3 percent in men assigned to placebo.
By contrast, dietary folate intake and plasma folate showed a trend toward reduced risk of prostate cancer, although the difference did not reach statistical significance. It remains unclear why dietary and circulating folate among non-multivitamin users may be inversely associated with risk, Figueiredo says.
“The synthetic form of folate, folic acid, found in supplements, is more bioavailable compared to folate from dietary sources and we know the amount of folate available is critical,” she says. “Adequate levels of folate may be beneficial, but too much folate is unlikely to be beneficial.”
Alternatively, these results may be due to chance, and replication by other studies is needed, she notes.
“These findings highlight the potentially complex role of folate in prostate cancer. The possibility of different effects from folic acid-containing supplements versus natural sources of folate definitely merits further investigation.”
Folic Acid Linked to Increased Cancer Rate
Two recent commentaries appearing in the November issue of Nutrition Reviews find that the introduction of flour fortified with folic acid into common foods was followed by an increase in colon cancer diagnoses in the U.S. and Canada. The two new review articles address these recent findings and provide an overview of the existing evidence on folic acid fortification and the associated policy issues.
For nearly a decade, folic acid, a chemical form of a common B vitamin (folate), has been added to wheat flour and other grain products in the U.S. and Canada. This public health measure was enacted after evidence was discovered linking folic acid with a reduced rate of a specific birth defect that affected the development of the spinal cord and central nervous system. During the same period, however, rates of colorectal cancer in the U.S. inexplicably began rising, even as regular colonoscopy check-ups became more common. In Canada, where folic acid supplementation was introduced a bit later, the same trend has been observed.
Dr. Solomons, author of one of the review commentaries, “Food Fortification with Folic Acid: Has the Other Shoe Dropped?” advises that a careful reconsideration of the fortification program is needed. “One size of dietary folic acid exposure does not fit all. It can be beneficial to some and detrimental to others at the same time,” comments Solomons.
Since the risk-benefit value of fortification varies according to age, Solomons suggests a reevaluation of the manner in which folic acid to prevent birth defects is delivered to the public. Among other things, targeting women of reproductive age while reducing folic acid levels in foods for which fortification is optional (such as ready-to-eat cereals and commercial drinks), would be worthy of consideration, in the opinion of Solomons.
As a result of noted birth defect reduction, 42 countries have implemented some form of mandatory folic acid fortification. The two commentaries stress the need to carefully consider and balance the risks and benefits associated with introducing such a program.
“Folic acid supplementation wields a double-edged sword,” remarks Dr. Young-In Kim, author of “Folic Acid Fortification and Supplementation—Good for Some but Not So Good for Others,” the other commentary review published in the November issue. According to Kim, “It may be beneficial or harmful, depending on the timing of intervention.” Exposure to high intakes of folic acid in early life and young adulthood may provide life-long protection from the tendency for cancer formation in different organs, such as the large intestines, whereas such exposures later in life, when cell damage has occurred, can spur on the advance of the tumor.
Thursday, May 20, 2010
Daily ginger consumption eases muscle pain
Ω
For centuries, ginger root has been used as a folk remedy for a variety of ailments such as colds and upset stomachs. But now, researchers at the University of Georgia have found that daily ginger consumption also reduces muscle pain caused by exercise.
While ginger had been shown to exert anti-inflammatory effects in rodents, its effect on experimentally-induced human muscle pain was largely unexplored, said Patrick O’Connor, a professor in the College of Education’s department of kinesiology. It was also believed that heating ginger, as occurs with cooking, might increase its pain-relieving effects.
O’Connor directed two studies examining the effects of 11 days of raw and heat-treated ginger supplementation on muscle pain. Collaborators included Chris Black, an assistant professor of kinesiology at Georgia College and State University in Milledgeville, UGA doctoral student Matt Herring and David Hurley, an associate professor of population health in UGA’s College of Veterinary Medicine.
Participants in the studies, 34 and 40 volunteers, respectively, consumed capsules containing two grams of either raw or heat-treated ginger or a placebo for 11 consecutive days. On the eighth day they performed 18 extensions of the elbow flexors with a heavy weight to induce moderate muscle injury to the arm. Arm function, inflammation, pain and a biochemical involved in pain were assessed prior to and for three days after exercise.
The studies showed that daily ginger supplementation reduced the exercise-induced pain by 25 percent, and the effect was not enhanced by heat-treating the ginger.
“The economic and personal costs of pain are extremely high,” said O’Connor. “Muscle pain generally is one of the most common types of pain and eccentric exercise-induced muscle pain specifically is a common type of injury related to sports and/or recreation (e.g., gardening). Anything that can truly relieve this type of pain will be greatly welcomed by the many people who are experiencing it.”
The study, which will be published in the September issue of The Journal of Pain, is currently available online at www.jpain.org/home.
For centuries, ginger root has been used as a folk remedy for a variety of ailments such as colds and upset stomachs. But now, researchers at the University of Georgia have found that daily ginger consumption also reduces muscle pain caused by exercise.
While ginger had been shown to exert anti-inflammatory effects in rodents, its effect on experimentally-induced human muscle pain was largely unexplored, said Patrick O’Connor, a professor in the College of Education’s department of kinesiology. It was also believed that heating ginger, as occurs with cooking, might increase its pain-relieving effects.
O’Connor directed two studies examining the effects of 11 days of raw and heat-treated ginger supplementation on muscle pain. Collaborators included Chris Black, an assistant professor of kinesiology at Georgia College and State University in Milledgeville, UGA doctoral student Matt Herring and David Hurley, an associate professor of population health in UGA’s College of Veterinary Medicine.
Participants in the studies, 34 and 40 volunteers, respectively, consumed capsules containing two grams of either raw or heat-treated ginger or a placebo for 11 consecutive days. On the eighth day they performed 18 extensions of the elbow flexors with a heavy weight to induce moderate muscle injury to the arm. Arm function, inflammation, pain and a biochemical involved in pain were assessed prior to and for three days after exercise.
The studies showed that daily ginger supplementation reduced the exercise-induced pain by 25 percent, and the effect was not enhanced by heat-treating the ginger.
“The economic and personal costs of pain are extremely high,” said O’Connor. “Muscle pain generally is one of the most common types of pain and eccentric exercise-induced muscle pain specifically is a common type of injury related to sports and/or recreation (e.g., gardening). Anything that can truly relieve this type of pain will be greatly welcomed by the many people who are experiencing it.”
The study, which will be published in the September issue of The Journal of Pain, is currently available online at www.jpain.org/home.
Abdominal fat at middle age associated with greater risk of dementia
Study confirms that obesity is associated with lower total brain volume
Researchers from Boston University School of Medicine determined that excess abdominal fat places otherwise healthy, middle-aged people at risk for dementia later in life. Preliminary findings suggest a relationship between obesity and dementia that could lead to promising prevention strategies in the future. Results of this study are published early online in Annals of Neurology, a journal of the American Neurological Association.
A 2005 World Health Organization (WHO) report estimated that 24.3 million people have some form of dementia, with 4.6 million new cases annually. Individuals with dementia exhibit a decline in short-term and long-term memory, language processing, problem solving capabilities, and other cognitive function. Clinical diagnosis of dementia is made when two or more brain functions are significantly impaired. Symptoms of dementia can be attributed to irreversible causes such Alzheimer's disease, vascular dementia, and Huntington's disease, or caused by treatable conditions such as brain tumor, medication reaction, or metabolic issues.
For the current study, Sudha Seshadri, M.D. and colleagues recruited participants from the Framingham Heart Study Offspring Cohort. The sample included 733 community participants who had a mean age of 60 years with roughly 70% of the study group comprised of women. Researchers examined the association between Body Mass Index (BMI), waist circumference, waist to hip ratio, CT-based measures of abdominal fat, with MRI measures of total brain volume (TCBV), temporal horn volume (THV), white matter hyperintensity volume (WMHV) and brain infarcts in the middle-aged participants.
"Our results confirm the inverse association of increasing BMI with lower brain volumes in older adults and with younger, middle-aged adults and extends the findings to a much larger study sample," noted Dr. Seshadri. Prior studies were conducted in cohorts with less than 300 participants and the current study includes over 700 individuals.
"More importantly our data suggests a stronger connection between central obesity, particularly the visceral fat component of abdominal obesity, and risk of dementia and Alzheimer's disease," Dr. Seshadri added. The research showed the association between VAT and TCBV was most robust and was also independent of BMI and insulin resistance. Researchers did not observe a statistically significant correlation between CT-based abdominal fat measures and THV, WMHV or BI.
"Our findings, while preliminary, provide greater understanding of the mechanisms underlying the link between obesity and dementia," concluded Dr. Seshadri. "Further studies will add to our knowledge and offer important methods of prevention."
Researchers from Boston University School of Medicine determined that excess abdominal fat places otherwise healthy, middle-aged people at risk for dementia later in life. Preliminary findings suggest a relationship between obesity and dementia that could lead to promising prevention strategies in the future. Results of this study are published early online in Annals of Neurology, a journal of the American Neurological Association.
A 2005 World Health Organization (WHO) report estimated that 24.3 million people have some form of dementia, with 4.6 million new cases annually. Individuals with dementia exhibit a decline in short-term and long-term memory, language processing, problem solving capabilities, and other cognitive function. Clinical diagnosis of dementia is made when two or more brain functions are significantly impaired. Symptoms of dementia can be attributed to irreversible causes such Alzheimer's disease, vascular dementia, and Huntington's disease, or caused by treatable conditions such as brain tumor, medication reaction, or metabolic issues.
For the current study, Sudha Seshadri, M.D. and colleagues recruited participants from the Framingham Heart Study Offspring Cohort. The sample included 733 community participants who had a mean age of 60 years with roughly 70% of the study group comprised of women. Researchers examined the association between Body Mass Index (BMI), waist circumference, waist to hip ratio, CT-based measures of abdominal fat, with MRI measures of total brain volume (TCBV), temporal horn volume (THV), white matter hyperintensity volume (WMHV) and brain infarcts in the middle-aged participants.
"Our results confirm the inverse association of increasing BMI with lower brain volumes in older adults and with younger, middle-aged adults and extends the findings to a much larger study sample," noted Dr. Seshadri. Prior studies were conducted in cohorts with less than 300 participants and the current study includes over 700 individuals.
"More importantly our data suggests a stronger connection between central obesity, particularly the visceral fat component of abdominal obesity, and risk of dementia and Alzheimer's disease," Dr. Seshadri added. The research showed the association between VAT and TCBV was most robust and was also independent of BMI and insulin resistance. Researchers did not observe a statistically significant correlation between CT-based abdominal fat measures and THV, WMHV or BI.
"Our findings, while preliminary, provide greater understanding of the mechanisms underlying the link between obesity and dementia," concluded Dr. Seshadri. "Further studies will add to our knowledge and offer important methods of prevention."
More physical activity leads to less obesity -- often, but not always
It may seem intuitive that greater amounts of exercise lead to less obesity, but an Indiana University study has found that this conventional wisdom applies primarily to white women. The findings draw attention not only to racial, ethnic and gender differences regarding exercise but also to the role work can play.
In his study involving more than 12,000 people in a nationally representative sample of U.S 20- to 64-year-olds, obesity expert Dong-Chul Seo found that obesity rates in general declined as the amount of weekly leisure-time physical activity (LTPA) increased. White women, however, saw the steepest decreases, particularly when meeting minimum national guidelines for weekly physical activity. This was not always the case for men and for women who were African American or Hispanic.
"For the majority of health professionals, even health researchers, they say the more leisure-time physical activity you engage in, the less likely you'll get obese," said Seo, associate professor in the School of Health, Physical Education and Recreation's Department of Applied Health Science. "This is true but it's probably only applicable to white women and some of the white men."
Surprised by the results, Seo looked deeper and found that job-related physical activity might have influenced obesity rates. Studies have found, for example, that men and Hispanic women are more likely to have manually demanding jobs than white women, which could affect the amount of LTPA they accumulate. For Hispanic women, their obesity rates dropped as their amount of occupational physical activity (OPA) increased. However, a different pattern was seen for men.
"This illustrates to me the importance of physical activity in the workplace," Seo said. "Workplace wellness programs should really be emphasized, especially for people who do sedentary work. To enhance their health, maybe employers could offer workout spaces and incentives to do physical activity during the work hours or right after. They can make it easier."
The study, published in the May issue of the Journal of Epidemiology and Community Health, is the first study that shows population-based evidence of a graded dose response relationship between the total volume of LTPA and obesity.
Here are more findings and information about the study:
• A body mass index of 30 or higher was considered obese. The age-adjusted rates of obesity were calculated according to six categories based on minimum national guidelines for physical activity: The obesity rate for women was 41.4 percent for those with no LTPA in the past month, 39.1 percent for those who engaged in LTPA but fell short of minimum national guidelines, 31 percent for those who met the minimum guidelines, 28 percent for those who exceeded the minimum guidelines but were within the first quartile of overachievers, 23.4 percent for the overachievers between the first and third quartile, and 19.5 percent for the overachievers at or above the third quartile.
• When this obesity rate is considered for women who are white, Hispanic and African American, the percentages are 40.6 percent, 41.5 percent and 51 percent, respectively, for those with no LTPA; 37.5 percent, 45.4 percent and 55.4 percent for those who engaged in LTPA but fell short of minimum national guidelines; 27.7 percent, 34.5 percent and 50 percent for those who met minimum guidelines; 26 percent, 33.8 percent and 44.5 percent for those who exceeded the minimum guidelines but were within the first quartile of overachievers; 16.5 percent, 38.5 percent and 46 percent for the overachievers between the first and third quartile; and 14, 41.6 and 38.1 percent for the overachievers at or above the third quartile.
• The age-adjusted rates of obesity for men were 31.4 percent for those with no LTPA in the past month, 29.5 percent for those who engaged in LTPA but fell short of minimum national guidelines, 29.8 percent for those who met the minimum guidelines, 27.9 percent for those who exceeded the minimum guidelines but were within the first quartile of overachievers, 26.7 percent for the overachievers between the first and third quartile, and 26.9 percent for the overachievers at or above the third quartile.
• The study sample of 12,227 people was drawn from National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2006. NHANES data is unique in that study participants are physically measured for height and weight rather than relying on self reports. The data also includes metabolic equivalents (MET) for study participants' leisure-time physical activity.
National guidelines call for a minimum of 450-750 MET minutes per week. MET is a way of quantifying the total amount of physical activity in a way that is comparable across various forms of physical activity. Walking briskly for 30 minutes, for example, is around 100 MET. Running 6 mph for 30 minutes is around 300 MET.
Seo said the biggest decline in obesity rates was seen between women who met the guidelines and those who participated in LTPA but fell short of the guidelines. He said this supports the effectiveness of the minimum guidelines at least in terms of weight control -- and it was only applicable to women.
In his study involving more than 12,000 people in a nationally representative sample of U.S 20- to 64-year-olds, obesity expert Dong-Chul Seo found that obesity rates in general declined as the amount of weekly leisure-time physical activity (LTPA) increased. White women, however, saw the steepest decreases, particularly when meeting minimum national guidelines for weekly physical activity. This was not always the case for men and for women who were African American or Hispanic.
"For the majority of health professionals, even health researchers, they say the more leisure-time physical activity you engage in, the less likely you'll get obese," said Seo, associate professor in the School of Health, Physical Education and Recreation's Department of Applied Health Science. "This is true but it's probably only applicable to white women and some of the white men."
Surprised by the results, Seo looked deeper and found that job-related physical activity might have influenced obesity rates. Studies have found, for example, that men and Hispanic women are more likely to have manually demanding jobs than white women, which could affect the amount of LTPA they accumulate. For Hispanic women, their obesity rates dropped as their amount of occupational physical activity (OPA) increased. However, a different pattern was seen for men.
"This illustrates to me the importance of physical activity in the workplace," Seo said. "Workplace wellness programs should really be emphasized, especially for people who do sedentary work. To enhance their health, maybe employers could offer workout spaces and incentives to do physical activity during the work hours or right after. They can make it easier."
The study, published in the May issue of the Journal of Epidemiology and Community Health, is the first study that shows population-based evidence of a graded dose response relationship between the total volume of LTPA and obesity.
Here are more findings and information about the study:
• A body mass index of 30 or higher was considered obese. The age-adjusted rates of obesity were calculated according to six categories based on minimum national guidelines for physical activity: The obesity rate for women was 41.4 percent for those with no LTPA in the past month, 39.1 percent for those who engaged in LTPA but fell short of minimum national guidelines, 31 percent for those who met the minimum guidelines, 28 percent for those who exceeded the minimum guidelines but were within the first quartile of overachievers, 23.4 percent for the overachievers between the first and third quartile, and 19.5 percent for the overachievers at or above the third quartile.
• When this obesity rate is considered for women who are white, Hispanic and African American, the percentages are 40.6 percent, 41.5 percent and 51 percent, respectively, for those with no LTPA; 37.5 percent, 45.4 percent and 55.4 percent for those who engaged in LTPA but fell short of minimum national guidelines; 27.7 percent, 34.5 percent and 50 percent for those who met minimum guidelines; 26 percent, 33.8 percent and 44.5 percent for those who exceeded the minimum guidelines but were within the first quartile of overachievers; 16.5 percent, 38.5 percent and 46 percent for the overachievers between the first and third quartile; and 14, 41.6 and 38.1 percent for the overachievers at or above the third quartile.
• The age-adjusted rates of obesity for men were 31.4 percent for those with no LTPA in the past month, 29.5 percent for those who engaged in LTPA but fell short of minimum national guidelines, 29.8 percent for those who met the minimum guidelines, 27.9 percent for those who exceeded the minimum guidelines but were within the first quartile of overachievers, 26.7 percent for the overachievers between the first and third quartile, and 26.9 percent for the overachievers at or above the third quartile.
• The study sample of 12,227 people was drawn from National Health and Nutrition Examination Survey (NHANES) data from 1999 to 2006. NHANES data is unique in that study participants are physically measured for height and weight rather than relying on self reports. The data also includes metabolic equivalents (MET) for study participants' leisure-time physical activity.
National guidelines call for a minimum of 450-750 MET minutes per week. MET is a way of quantifying the total amount of physical activity in a way that is comparable across various forms of physical activity. Walking briskly for 30 minutes, for example, is around 100 MET. Running 6 mph for 30 minutes is around 300 MET.
Seo said the biggest decline in obesity rates was seen between women who met the guidelines and those who participated in LTPA but fell short of the guidelines. He said this supports the effectiveness of the minimum guidelines at least in terms of weight control -- and it was only applicable to women.
Reducing niacin intake can prevent obesity
Dietary factors have long been known to play a major role in the development of obesity. The global increasing prevalence of obesity suggests that there should be some common changes in diet worldwide. In fact, a significant, yet, often neglected worldwide change in dietary factors in the past few decades is the food fortification-induced marked increase in the content of niacin. However, the effect of long-term exposure to excess niacin on human health remains to be unclear.
A research team from China examined the role of excess nicotinamide in glucose metabolism using co-loading of glucose and nicotinamide test. They proved that excess niacin intake-induced biphasic response, i.e., insulin resistance in the early phase and hypoglycemia in the late phase, may be a primary cause for the increased appetite in obesity. Their study will be published on May 21, 2010 in the World Journal of Gastroenterology.
The study also revealed for the first time that the obesity prevalence among US children and adolescents increased in parallel with the increase of the per capita niacin consumption with a 10-year lag, in which niacin fortification-induced sharp increase in niacin contents in grain products may play a major role. Reducing niacin intake and facilitating niacin elimination through sweat-inducing physical activity may be a key factor in the prevention and treatment of obesity.
It seems that the long-term safety of niacin fortification needs to be carefully evaluated.
A research team from China examined the role of excess nicotinamide in glucose metabolism using co-loading of glucose and nicotinamide test. They proved that excess niacin intake-induced biphasic response, i.e., insulin resistance in the early phase and hypoglycemia in the late phase, may be a primary cause for the increased appetite in obesity. Their study will be published on May 21, 2010 in the World Journal of Gastroenterology.
The study also revealed for the first time that the obesity prevalence among US children and adolescents increased in parallel with the increase of the per capita niacin consumption with a 10-year lag, in which niacin fortification-induced sharp increase in niacin contents in grain products may play a major role. Reducing niacin intake and facilitating niacin elimination through sweat-inducing physical activity may be a key factor in the prevention and treatment of obesity.
It seems that the long-term safety of niacin fortification needs to be carefully evaluated.
Jon's Health Tips - Latest Health Research
Previous health tips posts:
April 28
April 21
April 13
April 1
March 9
February 20
February 3
January 15
As I get older, so should the cheese I eat:
Probiotic (aged) cheese can help preserve and enhance the immune system of the elderly.
I know that eating nuts is good for me, and I try to eat a few every day – but this study makes me wonder if I should start eating more nuts – an awful lot of nuts – this study calls for 500 calories worth every day:
Eating Nuts = Better Cholesterol Levels
I'm taking Vitamin D tablets and not slathering on quite as much sunblock these days:
Researchers recommend pregnant women take 4,000 IU vitamin D a day
New Vitamin D recommendations for older men and women - Key recommendations: 800 to 1000 IU/day.
Vitamin D protects against diarrhea and colitis
Low vitamin D levels may be associated with more advanced physical disability and cognitive impairment in persons with multiple sclerosis.
I'm doing lots of things to avoid bone loss (although none actually for that reason):
Protein May Reduce Hip Fractures in the Elderly
Omega-3 May Help Reduce Bone Loss
Exercise Can Forestall Osteoporosis
Eating plenty of phytonutrients from colorful fruits and vegetables is associated with better bone health.
I've had to skin cancers on my face, one on each side, but I don't do much long-distance driving:
More Left-Side Skin Cancer - From Driving
I drink lots of tea, which is good for me in may ways:
Caffeine may help prevent cataract formation
Caffeine may slow Alzheimer's disease and other dementias, restore cognitive function, protect against Parkinson's, and improve mood.
I still eat oatmeal almost every day:
Diets rich in whole grain reduce risk of obesity and other diseases related to the metabolic syndrome e.g. type 2 diabetes and cardiovascular disease.
I eat dark chocolate almost every day:
Dark Chocolate May Guard Against Brain Injury From Stroke
I stopped taking C and E some time ago:
High doses of antioxidant supplements induce stem cell genetic abnormalities
Not my wife's - only walking in major cities (NYC, Paris, London, Barcelona) benefits hers:
Just five minutes of exercise in a park, working in a backyard garden, on a nature trail, or other green space will benefit mental health.
I've been eating too much meat lately (still not a lot):
Animal Protein Intake Increases Risk of Inflammatory Bowel Disease
But especially too much processed meat:
Eating processed meats, but not unprocessed red meats, may raise risk of heart disease and diabetes
But I've also kept up olive oil and nuts:
Olive, Peanut, and Grapeseed Oils May Protect Against the Development of Ulcerative Colitis
But not enough spicy food I guess:
Peppers May Help Lose Weight
Discouraging news:
1. No way to avoid Alzheimer's disease?
2. Restraining Calories Boosts Immunity
I hardly ever talk on my cell phone, and then only briefly:
World's biggest study on cell phones and brain cancer inconclusive
Unfortunately my aerobic exercise, biking and kayaking is weather and daylight dependent - and soccer, I'm told, isn't aerobic:
Benefits of aerobic training outclass those of lower-intensity walking programs
I've stopped taking my statin substitute until I make sure my liver is OK 9 statins and niacin, which I have alo stopped taking, can do real damage in rare cases) , but I hope to resume soon:
Statins decrease risk of clot-related diseases
April 28
April 21
April 13
April 1
March 9
February 20
February 3
January 15
As I get older, so should the cheese I eat:
Probiotic (aged) cheese can help preserve and enhance the immune system of the elderly.
I know that eating nuts is good for me, and I try to eat a few every day – but this study makes me wonder if I should start eating more nuts – an awful lot of nuts – this study calls for 500 calories worth every day:
Eating Nuts = Better Cholesterol Levels
Participants in the trials consumed an average of 67 grams (about 2.4 ounces) of nuts per day. This was associated with an average 5.1 percent reduction in total cholesterol concentration, a 7.4 percent reduction in low-density lipoprotein (LDL, or "bad" cholesterol) and an 8.3 percent change in ratio of LDL cholesterol to high-density lipoprotein (HDL, or "good" cholesterol). In addition, triglyceride levels declined by 10.2 percent among individuals with high triglyceride levels (at least 150 milligrams per deciliter), although not among those with lower levels.
I'm taking Vitamin D tablets and not slathering on quite as much sunblock these days:
Researchers recommend pregnant women take 4,000 IU vitamin D a day
New Vitamin D recommendations for older men and women - Key recommendations: 800 to 1000 IU/day.
Vitamin D protects against diarrhea and colitis
Low vitamin D levels may be associated with more advanced physical disability and cognitive impairment in persons with multiple sclerosis.
I'm doing lots of things to avoid bone loss (although none actually for that reason):
Protein May Reduce Hip Fractures in the Elderly
Seniors who consume a higher level of dietary protein are less likely to suffer hip fractures than seniors whose daily dietary protein intake is less.
Omega-3 May Help Reduce Bone Loss
NASA-sponsored studies have found that omega-3 fatty acids found in fish oil may play a role in mitigating bone breakdown that occurs during spaceflight and in osteoporosis.
Exercise Can Forestall Osteoporosis
Eating plenty of phytonutrients from colorful fruits and vegetables is associated with better bone health.
Green Phytonutrients: EGCG, lutein/zeaxanthin, isoflavones
Key Food Sources: tea, spinach, soybeans
Red Phytonutrient: lycopene
Key Food Sources: tomatoes and tomato products
White Phytonutrient: quercetin
Key Food Sources: onions
Yellow/Orange Phytonutrients: beta-carotene, hesperitin, beta-cryptoxanthin
Key Food Sources: carrots, oranges and orange juice
I've had to skin cancers on my face, one on each side, but I don't do much long-distance driving:
More Left-Side Skin Cancer - From Driving
A study found that facial skin cancers were predominantly on the left-side, and especially in men.
I drink lots of tea, which is good for me in may ways:
Caffeine may help prevent cataract formation
Caffeine may slow Alzheimer's disease and other dementias, restore cognitive function, protect against Parkinson's, and improve mood.
I still eat oatmeal almost every day:
Diets rich in whole grain reduce risk of obesity and other diseases related to the metabolic syndrome e.g. type 2 diabetes and cardiovascular disease.
I eat dark chocolate almost every day:
Dark Chocolate May Guard Against Brain Injury From Stroke
I stopped taking C and E some time ago:
High doses of antioxidant supplements induce stem cell genetic abnormalities
High doses of antioxidant nutritional supplements, such as vitamins C and E, can increase genetic abnormalities in cells, which may predispose supplement-takers to developing cancer, according to a new study from the Cedars-Sinai Heart Institute. .If you are taking 10 or 100 times the amount in a daily multivitamin, you may be predisposing your cells to developing cancer, therefore doing yourself more harm than good.
Not my wife's - only walking in major cities (NYC, Paris, London, Barcelona) benefits hers:
Just five minutes of exercise in a park, working in a backyard garden, on a nature trail, or other green space will benefit mental health.
I've been eating too much meat lately (still not a lot):
Animal Protein Intake Increases Risk of Inflammatory Bowel Disease
Animal protein represents a threefold risk of developing IBD in the highest intake group compared to the lowest group. Specifically, animal protein from meat and fish, not dairy, created an increased risk, while vegetable protein created no increased risk of developing IBD. The increased risk from animal protein intake were the same for Crohn's disease and ulcerative colitis.
But especially too much processed meat:
Eating processed meats, but not unprocessed red meats, may raise risk of heart disease and diabetes
In a new study, researchers from the Harvard School of Public Health (HSPH) have found that eating processed meat, such as bacon, sausage or processed deli meats, was associated with a 42% higher risk of heart disease and a 19% higher risk of type 2 diabetes. In contrast, the researchers did not find any higher risk of heart disease or diabetes among individuals eating unprocessed red meat, such as from beef, pork, or lamb.
The results showed that, on average, each 50 gram (1.8 oz) daily serving of processed meat (about 1-2 slices of deli meats or 1 hot dog) was associated with a 42% higher risk of developing heart disease and a 19% higher risk of developing diabetes. In contrast, eating unprocessed red meat was not associated with risk of developing heart disease or diabetes. Too few studies evaluated the relationship between eating meat and risk of stroke to enable the researchers to draw any conclusions.
"To lower risk of heart attacks and diabetes, people should consider which types of meats they are eating. Processed meats such as bacon, salami, sausages, hot dogs and processed deli meats may be the most important to avoid," said Micha. "Based on our findings, eating one serving per week or less would be associated with relatively small risk."
But I've also kept up olive oil and nuts:
Olive, Peanut, and Grapeseed Oils May Protect Against the Development of Ulcerative Colitis
But not enough spicy food I guess:
Peppers May Help Lose Weight
There is growing evidence that the body-heat-generating power of peppers might even lend a hand in our quest to lose those extra inches accumulating around our collective national waistline. And fortunately for those of us who don't appreciate the "burn" of hot peppers, there are plants that make a non-burning version of capsaicin called dihydrocapsiate (DCT) that could have the benefits of peppers without the pungency.
Discouraging news:
1. No way to avoid Alzheimer's disease?
Many preventive measures for cognitive decline and for preventing Alzheimer's disease -- mental stimulation, exercise, and a variety of dietary supplements -- have been studied over the years. However, an independent panel convened by the National Institutes of Health determined that the value of these strategies for delaying the onset and/or reducing the severity of decline or disease hasn't been demonstrated in rigorous studies.
2. Restraining Calories Boosts Immunity
Volunteers who followed a low-calorie diet or a very low-calorie diet not only lost weight, but also significantly enhanced their immune response. The study may be the first to demonstrate the interaction between calorie restriction and immune markers among humans.
I hardly ever talk on my cell phone, and then only briefly:
World's biggest study on cell phones and brain cancer inconclusive
Cell-phone users had lower brain cancer risks than non-users. However, the study also found heavy users of cell phones appeared to be at a higher risk of brain tumors than non-users.
Unfortunately my aerobic exercise, biking and kayaking is weather and daylight dependent - and soccer, I'm told, isn't aerobic:
Benefits of aerobic training outclass those of lower-intensity walking programs
What to do: walk around the block or work up a sweat in an aerobic workout at the gym? If you're looking for the best health benefits from an exercise program, a traditional aerobic fitness program that gets your heart pumping beats a walking program hands down. But if you want to get moving, a walking program is easier to do, it's good for you, and you're more likely to stick with it.
I've stopped taking my statin substitute until I make sure my liver is OK 9 statins and niacin, which I have alo stopped taking, can do real damage in rare cases) , but I hope to resume soon:
Statins decrease risk of clot-related diseases
Individuals at risk for heart attack and stroke may benefit from taking common cholesterol-lowering drugs known as statins, according to a study conducted by researchers at the University of Connecticut.
Wednesday, May 19, 2010
Statins decrease risk of clot-related diseases
Ω
Individuals at risk for clot-related diseases may benefit from taking common cholesterol-lowering drugs known as statins, according to a study conducted by researchers at the University of Connecticut.
The results of the study will be presented at the ATS 2010 International Conference in New Orleans.
"Previous clinical studies have indicated statins may play a role in lowering the risk of these conditions, but these studies have yielded variable estimates of the effect of statin therapy," said lead author Vanjul Agarwal, M.B.B.S. "In our study, we aimed to analyze and evaluate the effect of these drugs in patients with specific conditions related to vessel blockages."
While other studies have focused on the effects of specific statin drugs, Dr. Agarwal said the current analysis sought to evaluate the effect of statins as a whole. Researchers reviewed the results of 10 studies of more than 900,000 men and women evaluating the effect of statins in preventing venous thromboembolism (VTE), clots formed in the deep veins which pose a serious risk for heart attack and stroke. Dr. Agarwal noted that the current study included all types of VTE, with a focus on deep vein thrombosis (DVT), most commonly involving clots in the lower legs, and pulmonary embolism (PE), clots that form in the primary vessels of the lungs after migrating from other areas of the body, usually the legs, pelvis or, rarely, arms. According to study results, statin use benefited patients with all types of VTE, including DVT and PE.
Both PE and DVT can be asymptomatic and therefore difficult to detect, or easy to misdiagnose. According to the Centers for Disease Control, about 200,000 to 400,000 people in the U.S. have DVT and about 100,000 to 200,000 people have a PE. Nearly one-third of individuals with a PE die as a result of the condition.
Dr. Agarwal said statins are believed to decrease the risk of VTE by reducing inflammation, one of the factors involved in clot formation. "Statins have been found to have anti-inflammatory properties. Since thrombus formation involves inflammation, statins may reduce venous thrombus formation and thus, lower the odds of developing PE/DVT," she said.
Dr. Agarwal noted future randomized, controlled trials may help determine a course of statin therapy for patients most at risk for developing VTE.
"Patients at high risk for developing PE or DVT may be prescribed statins prophylactically," she said. "In these patients, regular use of statins could significantly reduce the incidence of PE and DVT."
Individuals at risk for clot-related diseases may benefit from taking common cholesterol-lowering drugs known as statins, according to a study conducted by researchers at the University of Connecticut.
The results of the study will be presented at the ATS 2010 International Conference in New Orleans.
"Previous clinical studies have indicated statins may play a role in lowering the risk of these conditions, but these studies have yielded variable estimates of the effect of statin therapy," said lead author Vanjul Agarwal, M.B.B.S. "In our study, we aimed to analyze and evaluate the effect of these drugs in patients with specific conditions related to vessel blockages."
While other studies have focused on the effects of specific statin drugs, Dr. Agarwal said the current analysis sought to evaluate the effect of statins as a whole. Researchers reviewed the results of 10 studies of more than 900,000 men and women evaluating the effect of statins in preventing venous thromboembolism (VTE), clots formed in the deep veins which pose a serious risk for heart attack and stroke. Dr. Agarwal noted that the current study included all types of VTE, with a focus on deep vein thrombosis (DVT), most commonly involving clots in the lower legs, and pulmonary embolism (PE), clots that form in the primary vessels of the lungs after migrating from other areas of the body, usually the legs, pelvis or, rarely, arms. According to study results, statin use benefited patients with all types of VTE, including DVT and PE.
Both PE and DVT can be asymptomatic and therefore difficult to detect, or easy to misdiagnose. According to the Centers for Disease Control, about 200,000 to 400,000 people in the U.S. have DVT and about 100,000 to 200,000 people have a PE. Nearly one-third of individuals with a PE die as a result of the condition.
Dr. Agarwal said statins are believed to decrease the risk of VTE by reducing inflammation, one of the factors involved in clot formation. "Statins have been found to have anti-inflammatory properties. Since thrombus formation involves inflammation, statins may reduce venous thrombus formation and thus, lower the odds of developing PE/DVT," she said.
Dr. Agarwal noted future randomized, controlled trials may help determine a course of statin therapy for patients most at risk for developing VTE.
"Patients at high risk for developing PE or DVT may be prescribed statins prophylactically," she said. "In these patients, regular use of statins could significantly reduce the incidence of PE and DVT."
Traditional aerobic fitness training trumps pedometer-based walking programs for health benefits
Ω
Benefits of aerobic training outclass those of lower-intensity walking programs
What to do: walk around the block or work up a sweat in an aerobic workout at the gym? If you're looking for the best health benefits from an exercise program, a traditional aerobic fitness program that gets your heart pumping beats a walking program hands down. But if you want to get moving, a walking program is easier to do, it's good for you, and you're more likely to stick with it.
University of Alberta researchers compared fitness training to a pedometer-based walking program, measuring the fitness and health outcomes of each. Programs were designed so participants would expend the same amount of energy in each regimen.
The six-month study, published by exercise physiologist, Gordon Bell, in the Faculty of Physical Education and Recreation, recruited 128 physically inactive men and women between 27 and 65 years of age with no known cardiovascular or other diseases. "Physically inactive" was defined by researchers as taking fewer than 5500 steps per day over a seven day period and not participating in any form of regular exercise.
Comparing fitness and walking groups, researchers found that after six months those in the supervised fitness program showed significantly greater reductions in
their systolic blood pressure (~9 per cent versus 3 per cent),
rating of perceived exertion ( 10 per cent versus no change), the effort measured during submaximal exercise
ventilatory threshold ( 15 per cent versus 4 per cent) – this is the point at which respiratory changes occur and respiration begins to become increasingly difficult during progressive exercise
peak VO2 , a measurement of peak oxygen intake (9 per cent versus 3 per cent).
At the start of the study, volunteers were randomized into the control group, the walking group or the exercise group and all were required to wear a pedometer for the duration of the study to ensure that they stayed within the prescribed number of steps.
"We gradually built up the number of steps that the walking group did until they were prescribed 10,000 steps per day to be completed every day of the week. They actually were able to complete 9221 steps per day or 92 per cent of the prescription," says Bell, noting the high adherence rate of the walking group to the target number of steps. "There's something to be said about the these types of programs where people can use a simple device at home, collect their steps throughout the day, and with no travel and little planning involved. People seem quite willing to adhere to that type of exercise when it can be done on their own time."
Participants in the fitness program had a more intense regimen. "Volunteers had to adhere to the intensity of exercise as measured by a heart-rate monitor, and to frequency, or number of times per week which as four times a week by the end of the study." Adherence based on frequency was 77 per cent in this group. Bell says this is close to what some researchers suggest as a successful adherence rate to this type of exercise program.
All participants saw benefits: walking and fitness training groups saw a significant reduction in body mass, waist circumference and waist-to-hip ratio after the six months as well as resting heart rate. Surprisingly, the control group saw changes too and Bell says it's possible they were motivated to be more physically active after undergoing the health assessment at the start of the study, and having a pedometer, which may have made them more aware of how much or little they were physically active.
"The participants in the traditional fitness program improved their fitness-based response more than those in the walking program," says Bell. "The magnitude of that difference in improvement was very clear."
However, he says, it's not the type of exercise program for everyone. "Not everybody's going to be able to start in a traditional exercise program, such as those with certain health issues or type 2 diabetes, because of the higher intensity, duration and frequency of exercise training that is required".
"Lifestyle and pedometer-based fitness programs make it easier to get started, as long as there are no lower limb issues or (one is not) severely overweight. Most people have the ability to walk and walking-based programs are easy to prescribe and progressively overload, and get people walking far enough to begin to derive health benefits from it."
But, cautions Bell, "It's a long-term commitment. It seems that you need at least six months to get some health benefits from walking based programs."
Benefits of aerobic training outclass those of lower-intensity walking programs
What to do: walk around the block or work up a sweat in an aerobic workout at the gym? If you're looking for the best health benefits from an exercise program, a traditional aerobic fitness program that gets your heart pumping beats a walking program hands down. But if you want to get moving, a walking program is easier to do, it's good for you, and you're more likely to stick with it.
University of Alberta researchers compared fitness training to a pedometer-based walking program, measuring the fitness and health outcomes of each. Programs were designed so participants would expend the same amount of energy in each regimen.
The six-month study, published by exercise physiologist, Gordon Bell, in the Faculty of Physical Education and Recreation, recruited 128 physically inactive men and women between 27 and 65 years of age with no known cardiovascular or other diseases. "Physically inactive" was defined by researchers as taking fewer than 5500 steps per day over a seven day period and not participating in any form of regular exercise.
Comparing fitness and walking groups, researchers found that after six months those in the supervised fitness program showed significantly greater reductions in
their systolic blood pressure (~9 per cent versus 3 per cent),
rating of perceived exertion ( 10 per cent versus no change), the effort measured during submaximal exercise
ventilatory threshold ( 15 per cent versus 4 per cent) – this is the point at which respiratory changes occur and respiration begins to become increasingly difficult during progressive exercise
peak VO2 , a measurement of peak oxygen intake (9 per cent versus 3 per cent).
At the start of the study, volunteers were randomized into the control group, the walking group or the exercise group and all were required to wear a pedometer for the duration of the study to ensure that they stayed within the prescribed number of steps.
"We gradually built up the number of steps that the walking group did until they were prescribed 10,000 steps per day to be completed every day of the week. They actually were able to complete 9221 steps per day or 92 per cent of the prescription," says Bell, noting the high adherence rate of the walking group to the target number of steps. "There's something to be said about the these types of programs where people can use a simple device at home, collect their steps throughout the day, and with no travel and little planning involved. People seem quite willing to adhere to that type of exercise when it can be done on their own time."
Participants in the fitness program had a more intense regimen. "Volunteers had to adhere to the intensity of exercise as measured by a heart-rate monitor, and to frequency, or number of times per week which as four times a week by the end of the study." Adherence based on frequency was 77 per cent in this group. Bell says this is close to what some researchers suggest as a successful adherence rate to this type of exercise program.
All participants saw benefits: walking and fitness training groups saw a significant reduction in body mass, waist circumference and waist-to-hip ratio after the six months as well as resting heart rate. Surprisingly, the control group saw changes too and Bell says it's possible they were motivated to be more physically active after undergoing the health assessment at the start of the study, and having a pedometer, which may have made them more aware of how much or little they were physically active.
"The participants in the traditional fitness program improved their fitness-based response more than those in the walking program," says Bell. "The magnitude of that difference in improvement was very clear."
However, he says, it's not the type of exercise program for everyone. "Not everybody's going to be able to start in a traditional exercise program, such as those with certain health issues or type 2 diabetes, because of the higher intensity, duration and frequency of exercise training that is required".
"Lifestyle and pedometer-based fitness programs make it easier to get started, as long as there are no lower limb issues or (one is not) severely overweight. Most people have the ability to walk and walking-based programs are easy to prescribe and progressively overload, and get people walking far enough to begin to derive health benefits from it."
But, cautions Bell, "It's a long-term commitment. It seems that you need at least six months to get some health benefits from walking based programs."
Eating processed meats, but not unprocessed red meats, may raise risk of heart disease and diabetes
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In a new study, researchers from the Harvard School of Public Health (HSPH) have found that eating processed meat, such as bacon, sausage or processed deli meats, was associated with a 42% higher risk of heart disease and a 19% higher risk of type 2 diabetes. In contrast, the researchers did not find any higher risk of heart disease or diabetes among individuals eating unprocessed red meat, such as from beef, pork, or lamb. This work is the first systematic review and meta-analysis of the worldwide evidence for how eating unprocessed red meat and processed meat relates to risk of cardiovascular diseases and diabetes.
"Although most dietary guidelines recommend reducing meat consumption, prior individual studies have shown mixed results for relationships between meat consumption and cardiovascular diseases and diabetes," said Renata Micha, a research fellow in the department of epidemiology at HSPH and lead author of the study. "Most prior studies also did not separately consider the health effects of eating unprocessed red versus processed meats."
The study appears online May 17, 2010, on the website of the journal Circulation.
The researchers, led by Renata Micha, a research fellow in the department of epidemiology, and HSPH colleagues Dariush Mozaffarian, assistant professor in the department of epidemiology and Sarah Wallace, junior research fellow in the department of epidemiology, systematically reviewed nearly 1,600 studies. Twenty relevant studies were identified, which included a total of 1,218,380 individuals from 10 countries on four continents (United States, Europe, Australia, and Asia).
The researchers defined unprocessed red meat as any unprocessed meat from beef, lamb or pork, excluding poultry. Processed meat was defined as any meat preserved by smoking, curing or salting, or with the addition of chemical preservatives; examples include bacon, salami, sausages, hot dogs or processed deli or luncheon meats. Vegetable or seafood protein sources were not evaluated in these studies.
The results showed that, on average, each 50 gram (1.8 oz) daily serving of processed meat (about 1-2 slices of deli meats or 1 hot dog) was associated with a 42% higher risk of developing heart disease and a 19% higher risk of developing diabetes. In contrast, eating unprocessed red meat was not associated with risk of developing heart disease or diabetes. Too few studies evaluated the relationship between eating meat and risk of stroke to enable the researchers to draw any conclusions.
"Although cause-and-effect cannot be proven by these types of long-term observational studies, all of these studies adjusted for other risk factors, which may have been different between people who were eating more versus less meats," said Mozaffarian. "Also, the lifestyle factors associated with eating unprocessed red meats and processed meats were similar, but only processed meats were linked to higher risk."
"When we looked at average nutrients in unprocessed red and processed meats eaten in the United States, we found that they contained similar average amounts of saturated fat and cholesterol. In contrast, processed meats contained, on average, 4 times more sodium and 50% more nitrate preservatives," said Micha. "This suggests that differences in salt and preservatives, rather than fats, might explain the higher risk of heart disease and diabetes seen with processed meats, but not with unprocessed red meats."
Dietary sodium (salt) is known to increase blood pressure, a strong risk factor for heart disease. In animal experiments, nitrate preservatives can promote atherosclerosis and reduce glucose tolerance, effects which could increase risk of heart disease and diabetes.
Given the differences in health risks seen with eating processed meats versus unprocessed red meats, these findings suggest that these types of meats should be studied separately in future research for health effects, including cancer, the authors said. For example, higher intake of total meat and processed meat has been associated with higher risk of colorectal cancer, but unprocessed red meat has not been separately evaluated. They also suggest that more research is needed into which factors (especially salt and other preservatives) in meats are most important for health effects.
Current efforts to update the United States government's Dietary Guidelines for Americans, which are often a reference for other countries around the world, make these findings particularly timely, the researchers say. They recommend that dietary and policy efforts should especially focus on reducing intake of processed meat.
"To lower risk of heart attacks and diabetes, people should consider which types of meats they are eating. Processed meats such as bacon, salami, sausages, hot dogs and processed deli meats may be the most important to avoid," said Micha. "Based on our findings, eating one serving per week or less would be associated with relatively small risk."
In a new study, researchers from the Harvard School of Public Health (HSPH) have found that eating processed meat, such as bacon, sausage or processed deli meats, was associated with a 42% higher risk of heart disease and a 19% higher risk of type 2 diabetes. In contrast, the researchers did not find any higher risk of heart disease or diabetes among individuals eating unprocessed red meat, such as from beef, pork, or lamb. This work is the first systematic review and meta-analysis of the worldwide evidence for how eating unprocessed red meat and processed meat relates to risk of cardiovascular diseases and diabetes.
"Although most dietary guidelines recommend reducing meat consumption, prior individual studies have shown mixed results for relationships between meat consumption and cardiovascular diseases and diabetes," said Renata Micha, a research fellow in the department of epidemiology at HSPH and lead author of the study. "Most prior studies also did not separately consider the health effects of eating unprocessed red versus processed meats."
The study appears online May 17, 2010, on the website of the journal Circulation.
The researchers, led by Renata Micha, a research fellow in the department of epidemiology, and HSPH colleagues Dariush Mozaffarian, assistant professor in the department of epidemiology and Sarah Wallace, junior research fellow in the department of epidemiology, systematically reviewed nearly 1,600 studies. Twenty relevant studies were identified, which included a total of 1,218,380 individuals from 10 countries on four continents (United States, Europe, Australia, and Asia).
The researchers defined unprocessed red meat as any unprocessed meat from beef, lamb or pork, excluding poultry. Processed meat was defined as any meat preserved by smoking, curing or salting, or with the addition of chemical preservatives; examples include bacon, salami, sausages, hot dogs or processed deli or luncheon meats. Vegetable or seafood protein sources were not evaluated in these studies.
The results showed that, on average, each 50 gram (1.8 oz) daily serving of processed meat (about 1-2 slices of deli meats or 1 hot dog) was associated with a 42% higher risk of developing heart disease and a 19% higher risk of developing diabetes. In contrast, eating unprocessed red meat was not associated with risk of developing heart disease or diabetes. Too few studies evaluated the relationship between eating meat and risk of stroke to enable the researchers to draw any conclusions.
"Although cause-and-effect cannot be proven by these types of long-term observational studies, all of these studies adjusted for other risk factors, which may have been different between people who were eating more versus less meats," said Mozaffarian. "Also, the lifestyle factors associated with eating unprocessed red meats and processed meats were similar, but only processed meats were linked to higher risk."
"When we looked at average nutrients in unprocessed red and processed meats eaten in the United States, we found that they contained similar average amounts of saturated fat and cholesterol. In contrast, processed meats contained, on average, 4 times more sodium and 50% more nitrate preservatives," said Micha. "This suggests that differences in salt and preservatives, rather than fats, might explain the higher risk of heart disease and diabetes seen with processed meats, but not with unprocessed red meats."
Dietary sodium (salt) is known to increase blood pressure, a strong risk factor for heart disease. In animal experiments, nitrate preservatives can promote atherosclerosis and reduce glucose tolerance, effects which could increase risk of heart disease and diabetes.
Given the differences in health risks seen with eating processed meats versus unprocessed red meats, these findings suggest that these types of meats should be studied separately in future research for health effects, including cancer, the authors said. For example, higher intake of total meat and processed meat has been associated with higher risk of colorectal cancer, but unprocessed red meat has not been separately evaluated. They also suggest that more research is needed into which factors (especially salt and other preservatives) in meats are most important for health effects.
Current efforts to update the United States government's Dietary Guidelines for Americans, which are often a reference for other countries around the world, make these findings particularly timely, the researchers say. They recommend that dietary and policy efforts should especially focus on reducing intake of processed meat.
"To lower risk of heart attacks and diabetes, people should consider which types of meats they are eating. Processed meats such as bacon, salami, sausages, hot dogs and processed deli meats may be the most important to avoid," said Micha. "Based on our findings, eating one serving per week or less would be associated with relatively small risk."
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