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Soda and other sugar-sweetened beverages such as fruit drinks are associated with higher blood pressure levels in adults, researchers report in Hypertension: Journal of the American Heart Association.
In the International Study of Macro/Micronutrients and Blood Pressure (INTERMAP), for every extra sugar-sweetened beverage drunk per day participants on average had significantly higher systolic blood pressure by 1.6 millimeters of mercury (mm Hg) and diastolic blood pressure higher by 0.8 mm Hg. This remained statistically significant even after adjusting for differences in body mass, researchers said.
Researchers found higher blood pressure levels in individuals who consumed more glucose and fructose, both sweeteners that are found in high-fructose corn syrup, the most common sugar sweetener used by the beverage industry.
Higher blood pressure was more pronounced in people who consumed high levels of both sugar and sodium. They found no consistent association between diet soda intake and blood pressure levels. Those who drank diet soda had higher mean BMI than those who did not and lower levels of physical activity.
"This points to another possible intervention to lower blood pressure," said Paul Elliott, Ph.D., senior author and professor in the Department of Epidemiology and Biostatistics in the School of Public Health at Imperial College London. "These findings lend support for recommendations to reduce the intake of sugar-sweetened beverages, as well as added sugars and sodium in an effort to reduce blood pressure and improve cardiovascular health."
In INTERMAP, researchers analyzed consumption of sugar-sweetened drinks, sugars and diet beverages in 2,696 participants, 40- to 59-years-old, in eight areas of the United States and two areas of the United Kingdom. Participants reported what they ate and drank for four days via in depth interviews administered by trained observers, underwent two 24-hour urine collections, eight blood pressure readings and responded a detailed questionnaire on lifestyle, medical and social factors.
The researchers found that sugar intake in the form of glucose, fructose and sucrose was highest in those consuming more than one sugar-sweetened beverage daily. They also found that individuals consuming more than one serving per day of sugar-sweetened beverages consumed more calories than those who didn't, with average energy intake of more than 397 calories per day.
Those who did not consume sugar-sweetened beverages had lower average body mass index (BMI) than those who consumed more than one of these drinks daily.
"People who drink a lot of sugar-sweetened beverages appear to have less healthy diets," said Ian Brown, Ph.D., research associate at Imperial College London. "They are consuming empty calories without the nutritional benefits of real food. They consume less potassium, magnesium and calcium.
"One possible mechanism for sugar-sweetened beverages and fructose increasing blood pressure levels is a resultant increase in the level of uric acid in the blood that may in turn lower the nitric oxide required to keep the blood vessels dilated. Sugar consumption also has been linked to enhanced sympathetic nervous system activity and sodium retention."
The study's limitations include that it was cross-sectional and diet was self-reported.
"This is a population study. It's one piece of the evidence in a jigsaw puzzle that needs to be completed," Brown said. "In the meantime, people who want to drink sugar-sweetened beverages should do so only in moderation."
The American Heart Association recommends no more than half of the discretionary calorie allowance from added sugars, which for most American women is no more than 100 calories per day and for most American men no more than 150 calories per day. Discretionary calories are the remaining calories in a person's "energy allowance" after consuming the recommended types and amounts of foods to meet all daily nutrient requirements.
Monday, February 28, 2011
Drinking Alcohol in Moderation Protects Against Heart Disease
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Individuals who drink alcohol in moderation (about one drink a day or less) are 14-25% less likely to develop heart disease compared to those who drink no alcohol at all, finds research led by Professor William Ghali from the University of Calgary, published online in the British Medical Journal.
The first paper, led by Paul Ronksley from the University of Calgary, emphasizes that a balance needs to be found between the public health message that consuming large amounts of alcohol is bad for you, and the one that drinking in moderation can have health benefits.
An accompanying paper led by Dr Susan Brien, also from the University of Calgary, finds that moderate consumption of alcohol (up to one drink or 15 g alcohol per day for women and up to two drinks or 30 g alcohol per day for men) is good for health. They say moderate amounts of alcohol significantly increase the levels of 'good' cholesterol circulating in the body and this has a protective effect against heart disease.
Brien and colleagues argue that their study strengthens the case that there is a causal link between alcohol consumption and reduced heart disease.
The authors of both papers acknowledge that a number of previous studies have concluded that moderate alcohol consumption has been associated with a decrease in heart disease. However, they say that the research was out-of-date and there was a need for new material. Professor Ghali says his team's research is the most comprehensive to date.
Ghali and colleagues reviewed 84 studies of alcohol consumption and heart disease. They compared alcohol drinkers with non-drinkers and their outcomes in relation to heart disease, death from heart disease, incidences of stroke and death from having a stroke.
In the companion study, Brien and colleagues reviewed 63 studies and investigated alcohol consumption with known physical markers for heart disease such as cholesterol, levels of inflammation, fat cells and the condition of blood vessels. They also assessed the impact of the type of alcohol consumed (wine, beer and spirits).
Interestingly, Brien's research concludes that it is the alcohol content that provides the health benefits not the type of alcoholic beverage (wine, beer or spirits) that is drunk.
Professor Ghali concludes that the debate between the impact of alcohol on heart disease should now centre "on how to integrate this evidence into clinical practice and public health messages."
He adds "with respect to public health messages there may now be an impetus to better communicate to the public that alcohol, in moderation, may have overall health benefits that outweigh the risks in selected subsets of patients … any such strategy would need to be accompanied by rigorous study and oversight of impacts."
Individuals who drink alcohol in moderation (about one drink a day or less) are 14-25% less likely to develop heart disease compared to those who drink no alcohol at all, finds research led by Professor William Ghali from the University of Calgary, published online in the British Medical Journal.
The first paper, led by Paul Ronksley from the University of Calgary, emphasizes that a balance needs to be found between the public health message that consuming large amounts of alcohol is bad for you, and the one that drinking in moderation can have health benefits.
An accompanying paper led by Dr Susan Brien, also from the University of Calgary, finds that moderate consumption of alcohol (up to one drink or 15 g alcohol per day for women and up to two drinks or 30 g alcohol per day for men) is good for health. They say moderate amounts of alcohol significantly increase the levels of 'good' cholesterol circulating in the body and this has a protective effect against heart disease.
Brien and colleagues argue that their study strengthens the case that there is a causal link between alcohol consumption and reduced heart disease.
The authors of both papers acknowledge that a number of previous studies have concluded that moderate alcohol consumption has been associated with a decrease in heart disease. However, they say that the research was out-of-date and there was a need for new material. Professor Ghali says his team's research is the most comprehensive to date.
Ghali and colleagues reviewed 84 studies of alcohol consumption and heart disease. They compared alcohol drinkers with non-drinkers and their outcomes in relation to heart disease, death from heart disease, incidences of stroke and death from having a stroke.
In the companion study, Brien and colleagues reviewed 63 studies and investigated alcohol consumption with known physical markers for heart disease such as cholesterol, levels of inflammation, fat cells and the condition of blood vessels. They also assessed the impact of the type of alcohol consumed (wine, beer and spirits).
Interestingly, Brien's research concludes that it is the alcohol content that provides the health benefits not the type of alcoholic beverage (wine, beer or spirits) that is drunk.
Professor Ghali concludes that the debate between the impact of alcohol on heart disease should now centre "on how to integrate this evidence into clinical practice and public health messages."
He adds "with respect to public health messages there may now be an impetus to better communicate to the public that alcohol, in moderation, may have overall health benefits that outweigh the risks in selected subsets of patients … any such strategy would need to be accompanied by rigorous study and oversight of impacts."
Thursday, February 24, 2011
Antioxidants in pecans may contribute to heart health and disease prevention
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A new research study from Loma Linda University (LLU) demonstrates that naturally occurring antioxidants in pecans may help contribute to heart health and disease prevention; the results were published in the January 2011 issue of The Journal of Nutrition.
Pecans contain different forms of the antioxidant vitamin E—known as tocopherols, plus numerous phenolic substances, many of them with antioxidant abilities. The nuts are especially rich in one form of vitamin E called gamma-tocopherols. The findings illustrate that after eating pecans, gamma-tocopherol levels in the body doubled and unhealthy oxidation of LDL (bad) cholesterol in the blood decreased by as much as 33 percent. Oxidized LDLs may further contribute to inflammation in the arteries and place people at greater risk of cardiovascular problems.
"Our tests show that eating pecans increases the amount of healthy antioxidants in the body," says LLU researcher Ella Haddad, DrPH, associate professor in the School of Public Health department of nutrition. "This protective effect is important in helping to prevent development of various diseases such as cancer and heart disease."
These findings are from a research project designed to further evaluate the health benefits of pecans, according to Dr. Haddad. She analyzed biomarkers in blood and urine samples from study participants (a total of 16 men and women between the ages 23 and 44) who ate a sequence of three diets composed of whole pecans, pecans blended with water, or a control meal of equivalent nutrient composition. The pecan meals contained about three ounces of the nut. Samples were taken prior to meals and at intervals up to 24 hours after eating.
Following the test meals composed of whole pecans and blended pecans, researchers found that amounts of gamma-tocopherols (vitamin E) in the body doubled eight hours after both meals, and oxygen radical absorbance capabilities (ORAC—a scientific method for measuring antioxidant power in the blood) increased 12 and 10 percent respectively two hours after the meals. In addition, following the whole-pecan meal, oxidized LDL cholesterol decreased by 30 percent (after 2 hours), 33 percent (after 3 hours), and 26 percent (after 8 hours).
"This study is another piece of evidence that pecans are a healthy food," says Dr. Haddad. "Previous research has shown that pecans contain antioxidant factors. Our study shows these antioxidants are indeed absorbed in the body and provide a protective effect against diseases."
Research from Loma Linda University published earlier in the Journal of Nutrition showed that a pecan-enriched diet lowered levels of LDL cholesterol by 16.5 percent—more than twice the American Heart Association's Step I diet, which was used as the control diet in that study. Similarly, the pecan-enriched diet lowered total cholesterol levels by 11.3 percent (also twice as much as the Step I diet).
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A new research study from Loma Linda University (LLU) demonstrates that naturally occurring antioxidants in pecans may help contribute to heart health and disease prevention; the results were published in the January 2011 issue of The Journal of Nutrition.
Pecans contain different forms of the antioxidant vitamin E—known as tocopherols, plus numerous phenolic substances, many of them with antioxidant abilities. The nuts are especially rich in one form of vitamin E called gamma-tocopherols. The findings illustrate that after eating pecans, gamma-tocopherol levels in the body doubled and unhealthy oxidation of LDL (bad) cholesterol in the blood decreased by as much as 33 percent. Oxidized LDLs may further contribute to inflammation in the arteries and place people at greater risk of cardiovascular problems.
"Our tests show that eating pecans increases the amount of healthy antioxidants in the body," says LLU researcher Ella Haddad, DrPH, associate professor in the School of Public Health department of nutrition. "This protective effect is important in helping to prevent development of various diseases such as cancer and heart disease."
These findings are from a research project designed to further evaluate the health benefits of pecans, according to Dr. Haddad. She analyzed biomarkers in blood and urine samples from study participants (a total of 16 men and women between the ages 23 and 44) who ate a sequence of three diets composed of whole pecans, pecans blended with water, or a control meal of equivalent nutrient composition. The pecan meals contained about three ounces of the nut. Samples were taken prior to meals and at intervals up to 24 hours after eating.
Following the test meals composed of whole pecans and blended pecans, researchers found that amounts of gamma-tocopherols (vitamin E) in the body doubled eight hours after both meals, and oxygen radical absorbance capabilities (ORAC—a scientific method for measuring antioxidant power in the blood) increased 12 and 10 percent respectively two hours after the meals. In addition, following the whole-pecan meal, oxidized LDL cholesterol decreased by 30 percent (after 2 hours), 33 percent (after 3 hours), and 26 percent (after 8 hours).
"This study is another piece of evidence that pecans are a healthy food," says Dr. Haddad. "Previous research has shown that pecans contain antioxidant factors. Our study shows these antioxidants are indeed absorbed in the body and provide a protective effect against diseases."
Research from Loma Linda University published earlier in the Journal of Nutrition showed that a pecan-enriched diet lowered levels of LDL cholesterol by 16.5 percent—more than twice the American Heart Association's Step I diet, which was used as the control diet in that study. Similarly, the pecan-enriched diet lowered total cholesterol levels by 11.3 percent (also twice as much as the Step I diet).
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Change in PSA Level Does Not Predict Prostate Cancer
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Screening for PSA Velocity Leads to Many Unnecessary Biopsies and Should Be Removed From Screening Guidelines
Researchers at Memorial Sloan-Kettering Cancer Center have found that change in PSA levels over time - known as PSA velocity - is a poor predictor of prostate cancer and may lead to many unnecessary biopsies. The new study of more than 5,000 men was published online February 24 in the Journal of the National Cancer Institute. Andrew Vickers, PhD, Associate Attending Research Methodologist in the Department of Epidemiology and Biostatistics and lead author said, "We have found no evidence to support the recommendation that men with a high PSA velocity should be biopsied in the absence of other indications. In other words, if a man's PSA has risen rapidly in recent years, there is no cause for concern if his total PSA level is still low and his clinical exam is normal."
Prostate cancer is the most common cancer among American men and the second leading cause of cancer deaths in men, according to the American Cancer Society. While PSA screening is widely used for the early detection of prostate cancer, it is also associated with a high rate of overdiagnosis, which can lead to unnecessary treatment and anxiety. Currently, early detection guidelines of several organizations (the National Cancer Center Network and the American Urological Association) recommend that men with a rapid rise in PSA - or a high PSA velocity - have a surgical biopsy for prostate cancer, even if there are no other indicators that cancer may exist. Those indicators could be an elevated baseline PSA or a positive digital rectal exam (DRE).
This study's population came from the Prostate Cancer Prevention Trial. Five thousand five hundred and nineteen men aged 55 years and older with no previous prostate cancer diagnosis, normal DRE, and a baseline PSA of 3.0 ng/mL or less were randomly assigned to finasteride - a drug commonly used to treat enlargement of the prostate gland, more commonly referred to as BPH, or benign prostatic hypertrophy - or placebo for seven years. This particular study focused on the men in the placebo group. The men were followed with yearly PSA tests, with biopsy recommended for men with a PSA higher than 4.0 ng/mL. After seven years, all men who were not diagnosed with prostate cancer were asked to consent to an end-of-study biopsy.
Dr. Vickers and colleagues found no important association between PSA velocity and biopsy outcome after adjusting for risk factors such as age, race, and PSA levels. PSA alone was a much better predictor of biopsy outcome than PSA velocity.
According to Peter T. Scardino, MD, Chair of the Department of Surgery, "This study should change practice. We have previously published papers determining that PSA naturally varies from month to month and have urged men whose PSA suddenly rises to wait six weeks and repeat the test before agreeing to a needle biopsy. This new study in a large population of men provides even stronger evidence that using changes in PSA as a basis for recommendation for biopsy leads to many more unnecessary biopsies and does not help to find the more aggressive cancers that we want to find and treat." Dr. Scardino added that "men should be cautious before rushing into a biopsy for minor variations in their PSA level."
Screening for PSA Velocity Leads to Many Unnecessary Biopsies and Should Be Removed From Screening Guidelines
Researchers at Memorial Sloan-Kettering Cancer Center have found that change in PSA levels over time - known as PSA velocity - is a poor predictor of prostate cancer and may lead to many unnecessary biopsies. The new study of more than 5,000 men was published online February 24 in the Journal of the National Cancer Institute. Andrew Vickers, PhD, Associate Attending Research Methodologist in the Department of Epidemiology and Biostatistics and lead author said, "We have found no evidence to support the recommendation that men with a high PSA velocity should be biopsied in the absence of other indications. In other words, if a man's PSA has risen rapidly in recent years, there is no cause for concern if his total PSA level is still low and his clinical exam is normal."
Prostate cancer is the most common cancer among American men and the second leading cause of cancer deaths in men, according to the American Cancer Society. While PSA screening is widely used for the early detection of prostate cancer, it is also associated with a high rate of overdiagnosis, which can lead to unnecessary treatment and anxiety. Currently, early detection guidelines of several organizations (the National Cancer Center Network and the American Urological Association) recommend that men with a rapid rise in PSA - or a high PSA velocity - have a surgical biopsy for prostate cancer, even if there are no other indicators that cancer may exist. Those indicators could be an elevated baseline PSA or a positive digital rectal exam (DRE).
This study's population came from the Prostate Cancer Prevention Trial. Five thousand five hundred and nineteen men aged 55 years and older with no previous prostate cancer diagnosis, normal DRE, and a baseline PSA of 3.0 ng/mL or less were randomly assigned to finasteride - a drug commonly used to treat enlargement of the prostate gland, more commonly referred to as BPH, or benign prostatic hypertrophy - or placebo for seven years. This particular study focused on the men in the placebo group. The men were followed with yearly PSA tests, with biopsy recommended for men with a PSA higher than 4.0 ng/mL. After seven years, all men who were not diagnosed with prostate cancer were asked to consent to an end-of-study biopsy.
Dr. Vickers and colleagues found no important association between PSA velocity and biopsy outcome after adjusting for risk factors such as age, race, and PSA levels. PSA alone was a much better predictor of biopsy outcome than PSA velocity.
According to Peter T. Scardino, MD, Chair of the Department of Surgery, "This study should change practice. We have previously published papers determining that PSA naturally varies from month to month and have urged men whose PSA suddenly rises to wait six weeks and repeat the test before agreeing to a needle biopsy. This new study in a large population of men provides even stronger evidence that using changes in PSA as a basis for recommendation for biopsy leads to many more unnecessary biopsies and does not help to find the more aggressive cancers that we want to find and treat." Dr. Scardino added that "men should be cautious before rushing into a biopsy for minor variations in their PSA level."
Tuesday, February 22, 2011
Aspirin, Cost-Effective Heart Disease Prevention
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Using aspirin for coronary heart prevention is less costly and more effective than doing nothing in men older than 45 with more than 10 percent 10-year-risk of the disease, according to a study by researchers at RTI International, University of Michigan, and University of North Carolina at Chapel Hill.
The study, published online in the Archives of Internal Medicine, used a Markov model to compare the costs and outcomes of prescribing low-dose aspirin alone, aspirin plus a proton-pump inhibitor, or no treatment for coronary heart prevention. The researchers specifically considered the effects of each treatment on cardiovascular events and risk of upper gastrointestinal bleeding.
"This analysis supports the role of aspirin for primary prevention of cardio heart disease events in middle-aged men across a range of cardio heart disease and gastrointestinal bleeding risk levels," said Stephanie Earnshaw, Ph.D., a health economist at RTI Health Solutions, a business unit of RTI, and the paper's lead author.
"Increased risk of gastrointestinal bleeding does not reduce aspirin's net benefit until gastrointestinal bleeding risk becomes quite high."
The researchers also found that adding proton pump inhibitors was not cost-effective for men with average gastrointestinal tract bleeding, but may be cost-effective for selected men at increased risk for gastrointestinal bleeding.
Using aspirin for coronary heart prevention is less costly and more effective than doing nothing in men older than 45 with more than 10 percent 10-year-risk of the disease, according to a study by researchers at RTI International, University of Michigan, and University of North Carolina at Chapel Hill.
The study, published online in the Archives of Internal Medicine, used a Markov model to compare the costs and outcomes of prescribing low-dose aspirin alone, aspirin plus a proton-pump inhibitor, or no treatment for coronary heart prevention. The researchers specifically considered the effects of each treatment on cardiovascular events and risk of upper gastrointestinal bleeding.
"This analysis supports the role of aspirin for primary prevention of cardio heart disease events in middle-aged men across a range of cardio heart disease and gastrointestinal bleeding risk levels," said Stephanie Earnshaw, Ph.D., a health economist at RTI Health Solutions, a business unit of RTI, and the paper's lead author.
"Increased risk of gastrointestinal bleeding does not reduce aspirin's net benefit until gastrointestinal bleeding risk becomes quite high."
The researchers also found that adding proton pump inhibitors was not cost-effective for men with average gastrointestinal tract bleeding, but may be cost-effective for selected men at increased risk for gastrointestinal bleeding.
Higher vitamin D intake needed to reduce cancer risk
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Researchers at the University of California, San Diego School of Medicine and Creighton University School of Medicine in Omaha have reported that markedly higher intake of vitamin D is needed to reach blood levels that can prevent or markedly cut the incidence of breast cancer and several other major diseases than had been originally thought. The findings are published February 21 in the journal Anticancer Research
While these levels are higher than traditional intakes, they are largely in a range deemed safe for daily use in a December 2010 report from the National Academy of Sciences Institute of Medicine.
"We found that daily intakes of vitamin D by adults in the range of 4000-8000 IU are needed to maintain blood levels of vitamin D metabolites in the range needed to reduce by about half the risk of several diseases - breast cancer, colon cancer, multiple sclerosis, and type 1 diabetes," said Cedric Garland, DrPH, professor of family and preventive medicine at UC San Diego Moores Cancer Center. "I was surprised to find that the intakes required to maintain vitamin D status for disease prevention were so high – much higher than the minimal intake of vitamin D of 400 IU/day that was needed to defeat rickets in the 20th century."
"I was not surprised by this" said Robert P. Heaney, MD, of Creighton University, a distinguished biomedical scientist who has studied vitamin D need for several decades. "This result was what our dose-response studies predicted, but it took a study such as this, of people leading their everyday lives, to confirm it."
The study reports on a survey of several thousand volunteers who were taking vitamin D supplements in the dosage range from 1000 to 10,000 IU/day. Blood studies were conducted to determine the level of 25-vitamin D – the form in which almost all vitamin D circulates in the blood.
"Most scientists who are actively working with vitamin D now believe that 40 to 60 ng/ml is the appropriate target concentration of 25-vitamin D in the blood for preventing the major vitamin D-deficiency related diseases, and have joined in a letter on this topic," said Garland. "Unfortunately, according a recent National Health and Nutrition Examination Survey, only 10 percent of the US population has levels in this range, mainly people who work outdoors."
Interest in larger doses was spurred in December of last year, when a National Academy of Sciences Institute of Medicine committee identified 4000 IU/day of vitamin D as safe for every day use by adults and children nine years and older, with intakes in the range of 1000-3000 IU/day for infants and children through age eight years old.
While the IOM committee states that 4000 IU/day is a safe dosage, the recommended minimum daily intake is only 600 IU/day.
"Now that the results of this study are in, it will become common for almost every adult to take 4000 IU/day," Garland said. "This is comfortably under the 10,000 IU/day that the IOM Committee Report considers as the lower limit of risk, and the benefits are substantial." He added that people who may have contraindications should discuss their vitamin D needs with their family doctor.
"Now is the time for virtually everyone to take more vitamin D to help prevent some major types of cancer, several other serious illnesses, and fractures," said Heaney.
Researchers at the University of California, San Diego School of Medicine and Creighton University School of Medicine in Omaha have reported that markedly higher intake of vitamin D is needed to reach blood levels that can prevent or markedly cut the incidence of breast cancer and several other major diseases than had been originally thought. The findings are published February 21 in the journal Anticancer Research
While these levels are higher than traditional intakes, they are largely in a range deemed safe for daily use in a December 2010 report from the National Academy of Sciences Institute of Medicine.
"We found that daily intakes of vitamin D by adults in the range of 4000-8000 IU are needed to maintain blood levels of vitamin D metabolites in the range needed to reduce by about half the risk of several diseases - breast cancer, colon cancer, multiple sclerosis, and type 1 diabetes," said Cedric Garland, DrPH, professor of family and preventive medicine at UC San Diego Moores Cancer Center. "I was surprised to find that the intakes required to maintain vitamin D status for disease prevention were so high – much higher than the minimal intake of vitamin D of 400 IU/day that was needed to defeat rickets in the 20th century."
"I was not surprised by this" said Robert P. Heaney, MD, of Creighton University, a distinguished biomedical scientist who has studied vitamin D need for several decades. "This result was what our dose-response studies predicted, but it took a study such as this, of people leading their everyday lives, to confirm it."
The study reports on a survey of several thousand volunteers who were taking vitamin D supplements in the dosage range from 1000 to 10,000 IU/day. Blood studies were conducted to determine the level of 25-vitamin D – the form in which almost all vitamin D circulates in the blood.
"Most scientists who are actively working with vitamin D now believe that 40 to 60 ng/ml is the appropriate target concentration of 25-vitamin D in the blood for preventing the major vitamin D-deficiency related diseases, and have joined in a letter on this topic," said Garland. "Unfortunately, according a recent National Health and Nutrition Examination Survey, only 10 percent of the US population has levels in this range, mainly people who work outdoors."
Interest in larger doses was spurred in December of last year, when a National Academy of Sciences Institute of Medicine committee identified 4000 IU/day of vitamin D as safe for every day use by adults and children nine years and older, with intakes in the range of 1000-3000 IU/day for infants and children through age eight years old.
While the IOM committee states that 4000 IU/day is a safe dosage, the recommended minimum daily intake is only 600 IU/day.
"Now that the results of this study are in, it will become common for almost every adult to take 4000 IU/day," Garland said. "This is comfortably under the 10,000 IU/day that the IOM Committee Report considers as the lower limit of risk, and the benefits are substantial." He added that people who may have contraindications should discuss their vitamin D needs with their family doctor.
"Now is the time for virtually everyone to take more vitamin D to help prevent some major types of cancer, several other serious illnesses, and fractures," said Heaney.
Monday, February 21, 2011
Endurance Exercise Prevents Premature Aging
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Endurance exercise may stop you looking and feeling old, it may even help you live longer, a study by McMaster University researchers has found.
“Many people falsely believe that the benefits of exercise will be found in a pill,” said Mark Tarnopolsky, principal investigator of the study and a professor of pediatrics and medicine of the Michael G. DeGroote School of Medicine. “We have clearly shown that there is no substitute for the “real thing” of exercise when it comes to protection from aging.”
The study, published today in the prestigious science journal Proceedings of the National Academy of Sciences (PNAS), found that premature aging in nearly every organ in the body was completely prevented in mice that ran on a treadmill three times a week for five months.
These mice were genetically engineered to age faster due to a defect in a gene for polymerase gamma (POLG1) that alters the repair system of their mitochondria – the cellular powerhouses responsible for generating energy for nearly every cell in the body.
Mitochondria are unique in that they have their own DNA. It has been thought that lifelong accumulation of mitochondrial DNA mutations lead to energy crisis that result in a progressive decline in tissue and organ function, ultimately resulting in aging. But the study on genetically-disadvantaged mice found those who had endurance exercise training three times a week looked as young as healthy mice while their sedentary siblings were balding, graying, physically inactive, socially isolated and less fertile.
“Others have tried to treat these animals with “exercise pill” drugs and have even tried to reduce their caloric intake, a strategy felt to be the most effective for slowing aging, and these were met with limited success,” said Tarnopolsky.
Adeel Safdar, lead author and a senior PhD student working with Tarnopolsky said: “I believe that we have very compelling evidence that clearly show that endurance exercise is a lifestyle approach that improves whole body mitochondrial function which is critical for reducing morbidity and mortality. Exercise truly is the fountain of youth.”
Co-author Jacqueline Bourgeois said: “The recipe for healthy aging is very simple, and that’s exercise. The problem is that it is most people find it a difficult recipe to follow.”
Endurance exercise may stop you looking and feeling old, it may even help you live longer, a study by McMaster University researchers has found.
“Many people falsely believe that the benefits of exercise will be found in a pill,” said Mark Tarnopolsky, principal investigator of the study and a professor of pediatrics and medicine of the Michael G. DeGroote School of Medicine. “We have clearly shown that there is no substitute for the “real thing” of exercise when it comes to protection from aging.”
The study, published today in the prestigious science journal Proceedings of the National Academy of Sciences (PNAS), found that premature aging in nearly every organ in the body was completely prevented in mice that ran on a treadmill three times a week for five months.
These mice were genetically engineered to age faster due to a defect in a gene for polymerase gamma (POLG1) that alters the repair system of their mitochondria – the cellular powerhouses responsible for generating energy for nearly every cell in the body.
Mitochondria are unique in that they have their own DNA. It has been thought that lifelong accumulation of mitochondrial DNA mutations lead to energy crisis that result in a progressive decline in tissue and organ function, ultimately resulting in aging. But the study on genetically-disadvantaged mice found those who had endurance exercise training three times a week looked as young as healthy mice while their sedentary siblings were balding, graying, physically inactive, socially isolated and less fertile.
“Others have tried to treat these animals with “exercise pill” drugs and have even tried to reduce their caloric intake, a strategy felt to be the most effective for slowing aging, and these were met with limited success,” said Tarnopolsky.
Adeel Safdar, lead author and a senior PhD student working with Tarnopolsky said: “I believe that we have very compelling evidence that clearly show that endurance exercise is a lifestyle approach that improves whole body mitochondrial function which is critical for reducing morbidity and mortality. Exercise truly is the fountain of youth.”
Co-author Jacqueline Bourgeois said: “The recipe for healthy aging is very simple, and that’s exercise. The problem is that it is most people find it a difficult recipe to follow.”
Thursday, February 17, 2011
Vitamin E may increase or decrease the risk of pneumonia depending on smoking and exercise
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Depending on the level of smoking and leisure time exercise, vitamin E supplementation may decrease or increase, or may have no effect, on the risk of pneumonia, according to a study published in Clinical Epidemiology.
In laboratory studies, vitamin E has influenced the immune system. In several animal studies vitamin E protected against viral and bacterial infections. However, the importance of vitamin E on human infections is not known.
Dr. Harri Hemila and Professor Jaakko Kaprio, of the University of Helsinki, Finland, studied the effect of vitamin E on the risk of pneumonia in the large randomized trial (Alpha-Tocopherol Beta-Carotene Cancer Prevention Study) which was conducted in Finland between 1985-1993. There were 898 cases of pneumonia among 29,133 participants of the study.
Vitamin E had no overall effect on pneumonia risk. However, vitamin E decreased pneumonia risk by 69% among participants who had the least exposure to smoking and exercised during leisure time. In contrast, vitamin E increased pneumonia risk by 79% among those who had the highest exposure to smoking and did not exercise. Over half of the participants were outside of these two subgroups and vitamin E did not affect their risk of pneumonia. Thus, the beneficial and harmful effects of vitamin E are restricted to fairly small parts of the population. The researchers concluded the role of vitamin E in susceptibility to pneumonia in physically active nonsmokers warrants further study.
Depending on the level of smoking and leisure time exercise, vitamin E supplementation may decrease or increase, or may have no effect, on the risk of pneumonia, according to a study published in Clinical Epidemiology.
In laboratory studies, vitamin E has influenced the immune system. In several animal studies vitamin E protected against viral and bacterial infections. However, the importance of vitamin E on human infections is not known.
Dr. Harri Hemila and Professor Jaakko Kaprio, of the University of Helsinki, Finland, studied the effect of vitamin E on the risk of pneumonia in the large randomized trial (Alpha-Tocopherol Beta-Carotene Cancer Prevention Study) which was conducted in Finland between 1985-1993. There were 898 cases of pneumonia among 29,133 participants of the study.
Vitamin E had no overall effect on pneumonia risk. However, vitamin E decreased pneumonia risk by 69% among participants who had the least exposure to smoking and exercised during leisure time. In contrast, vitamin E increased pneumonia risk by 79% among those who had the highest exposure to smoking and did not exercise. Over half of the participants were outside of these two subgroups and vitamin E did not affect their risk of pneumonia. Thus, the beneficial and harmful effects of vitamin E are restricted to fairly small parts of the population. The researchers concluded the role of vitamin E in susceptibility to pneumonia in physically active nonsmokers warrants further study.
Higher levels of social activity decrease the risk of developing disability in old age
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Afraid of becoming disabled in old age, not being able to dress yourself or walk up and down the stairs? Staying physically active before symptoms set in could help. But so could going out to eat, playing bingo and taking overnight trips.
According to research conducted at Rush University Medical Center, higher levels of social activity are associated with a decreased risk of becoming disabled. The study has just been posted online and will be published in the April issue of the Journal of Gerontology: Medical Sciences.
"Social activity has long been recognized as an essential component of healthy aging, but now we have strong evidence that it is also related to better everyday functioning and less disability in old age," said lead researcher Bryan James, PhD, postdoctoral fellow in the epidemiology of aging and dementia in the Rush Alzheimer's Disease Center. "The findings are exciting because social activity is potentially a risk factor that can be modified to help older adults avoid the burdens of disability."
The study included 954 older adults with a mean age of 82 who are participating in the Rush Memory and Aging Project, an ongoing longitudinal study of common chronic conditions of aging. At the start of the investigation, none of the participants had any form of disability. They each underwent yearly evaluations that included a medical history and neurological and neuropsychological tests.
Social activity was measured based on a questionnaire that assessed whether, and how often, participants went to restaurants, sporting events or the teletract (off-track betting) or played bingo; went on day trips or overnight trips; did volunteer work; visited relatives or friends; participated in groups such as the Knights of Columbus; or attended religious services.
To assess disability, participants were asked whether they could perform six activities of daily living without help: feeding, bathing, dressing, toileting, transferring and walking across a small room. They were also asked whether they could perform three tasks that require mobility and strength: walking up and down a flight of stairs, walking a half mile and doing heavy housework. Finally, they were asked about their ability to perform what are referred to as "instrumental" activities of daily living, such as using the telephone, preparing meals and managing medications. Difficulties with household management and mobility are more common and represent less severe disability than difficulty with self-care tasks, so the measures represented a range of disability.
Results showed that a person who reported a high level of social activity was about twice as likely to remain free of a disability involving activities of daily living than a person with a low level of social activity, and about 1.5 times as likely to remain free of disability involving instrumental activities of daily living or mobility.
Why social activity plays a role in the development of disability is not clear, James said. Possibly, social activity may reinforce the neural networks and musculoskeletal function required to maintain functional independence.
Future research is needed to determine whether interventions aimed at increasing late-life social activity can play a part in delaying or preventing disability, James said.
Afraid of becoming disabled in old age, not being able to dress yourself or walk up and down the stairs? Staying physically active before symptoms set in could help. But so could going out to eat, playing bingo and taking overnight trips.
According to research conducted at Rush University Medical Center, higher levels of social activity are associated with a decreased risk of becoming disabled. The study has just been posted online and will be published in the April issue of the Journal of Gerontology: Medical Sciences.
"Social activity has long been recognized as an essential component of healthy aging, but now we have strong evidence that it is also related to better everyday functioning and less disability in old age," said lead researcher Bryan James, PhD, postdoctoral fellow in the epidemiology of aging and dementia in the Rush Alzheimer's Disease Center. "The findings are exciting because social activity is potentially a risk factor that can be modified to help older adults avoid the burdens of disability."
The study included 954 older adults with a mean age of 82 who are participating in the Rush Memory and Aging Project, an ongoing longitudinal study of common chronic conditions of aging. At the start of the investigation, none of the participants had any form of disability. They each underwent yearly evaluations that included a medical history and neurological and neuropsychological tests.
Social activity was measured based on a questionnaire that assessed whether, and how often, participants went to restaurants, sporting events or the teletract (off-track betting) or played bingo; went on day trips or overnight trips; did volunteer work; visited relatives or friends; participated in groups such as the Knights of Columbus; or attended religious services.
To assess disability, participants were asked whether they could perform six activities of daily living without help: feeding, bathing, dressing, toileting, transferring and walking across a small room. They were also asked whether they could perform three tasks that require mobility and strength: walking up and down a flight of stairs, walking a half mile and doing heavy housework. Finally, they were asked about their ability to perform what are referred to as "instrumental" activities of daily living, such as using the telephone, preparing meals and managing medications. Difficulties with household management and mobility are more common and represent less severe disability than difficulty with self-care tasks, so the measures represented a range of disability.
Results showed that a person who reported a high level of social activity was about twice as likely to remain free of a disability involving activities of daily living than a person with a low level of social activity, and about 1.5 times as likely to remain free of disability involving instrumental activities of daily living or mobility.
Why social activity plays a role in the development of disability is not clear, James said. Possibly, social activity may reinforce the neural networks and musculoskeletal function required to maintain functional independence.
Future research is needed to determine whether interventions aimed at increasing late-life social activity can play a part in delaying or preventing disability, James said.
Wednesday, February 16, 2011
Bisphosphonates, acting like statins, fight colorectal cancer."
As previously reported, Australian clinical researchers have noted an extraordinary and unexpected benefit of osteoporosis treatment – that people taking bisphosphonates are not only surviving well, better than people without osteoporosis, they appear to be gaining an extra five years of life. These findings are published in the Journal of Clinical Endocrinology and Metabolism.
Now, an international team of researchers has found that the use of bisphosphonates - drugs already taken by millions of healthy women to prevent bone-loss - for more than one year was associated with a 50 percent reduction in the risk of postmenopausal colorectal cancer. The results were published this week in the Journal of Clinical Oncology.
According to lead researcher Prof. Gad Rennert, M.D., Ph.D., of the Technion-Israel Institute of Technology Faculty of Medicine and chairman of the Department of Community Medicine and Epidemiology at the Carmel Medical Center of Clalit Health Services, these findings further support the role of bisphosphonates as a possible new drug class for cancer prevention.
"We formerly identified a new class of drugs associated with a reduced risk of breast cancer," said Rennert. "And, now, by showing a similar effect on colorectal cancer risk reduction, we can assume that this class of medications has a broad effect - not necessarily limited to a specific cancer site." Such an effect, if proven in randomized trials, could lead to the recommendation for the use of these medications by the general population for cancer prevention, he added.
Rennert and colleagues extracted data from the Molecular Epidemiology of Colorectal Cancer (MECC) study, a population-based case-control study in northern Israel, conducted together with senior author Stephen Gruber, M.D., MPH, Ph.D. of the University of Michigan, Ann Arbor. Using pharmacy records, the team evaluated the use of bisphosphonates in 1,866 postmenopausal female participants.
The researchers found that the use of bisphosphonates prior to diagnosis was strongly associated with a significant reduced relative risk for colorectal cancer - even after making adjustments for a large variety of known risk or protective factors for colorectal cancer such as family history, dietary components, physical activity, body mass index, and the use of other medications such as aspirin, statins and hormone replacement therapy.
"Bisphosphonates share the same mevalonate metabolic pathway as do statins, which we have previously shown to be associated with risk reduction of colorectal cancer," said Dr. Gruber. "This fact adds to the credibility of the current finding by adding biological plausibility."
Colorectal cancer is among the leading cancers in western countries, with more than 150,000 new cases diagnosed every year. In the U.S. alone, colorectal cancer kills some 50,000 deaths per year, making it one of the country's leading causes of cancer death.
"While the disease is generally caused by bad dietary habits and lack of physical activity, it can possibly be prevented by several medications, such as aspirin and cholesterol-lowering medication of the statins group," said Prof. Rennert. "And now, we can add bisphosphonates to the list of tools for potential prevention of colorectal cancer."
Now, an international team of researchers has found that the use of bisphosphonates - drugs already taken by millions of healthy women to prevent bone-loss - for more than one year was associated with a 50 percent reduction in the risk of postmenopausal colorectal cancer. The results were published this week in the Journal of Clinical Oncology.
According to lead researcher Prof. Gad Rennert, M.D., Ph.D., of the Technion-Israel Institute of Technology Faculty of Medicine and chairman of the Department of Community Medicine and Epidemiology at the Carmel Medical Center of Clalit Health Services, these findings further support the role of bisphosphonates as a possible new drug class for cancer prevention.
"We formerly identified a new class of drugs associated with a reduced risk of breast cancer," said Rennert. "And, now, by showing a similar effect on colorectal cancer risk reduction, we can assume that this class of medications has a broad effect - not necessarily limited to a specific cancer site." Such an effect, if proven in randomized trials, could lead to the recommendation for the use of these medications by the general population for cancer prevention, he added.
Rennert and colleagues extracted data from the Molecular Epidemiology of Colorectal Cancer (MECC) study, a population-based case-control study in northern Israel, conducted together with senior author Stephen Gruber, M.D., MPH, Ph.D. of the University of Michigan, Ann Arbor. Using pharmacy records, the team evaluated the use of bisphosphonates in 1,866 postmenopausal female participants.
The researchers found that the use of bisphosphonates prior to diagnosis was strongly associated with a significant reduced relative risk for colorectal cancer - even after making adjustments for a large variety of known risk or protective factors for colorectal cancer such as family history, dietary components, physical activity, body mass index, and the use of other medications such as aspirin, statins and hormone replacement therapy.
"Bisphosphonates share the same mevalonate metabolic pathway as do statins, which we have previously shown to be associated with risk reduction of colorectal cancer," said Dr. Gruber. "This fact adds to the credibility of the current finding by adding biological plausibility."
Colorectal cancer is among the leading cancers in western countries, with more than 150,000 new cases diagnosed every year. In the U.S. alone, colorectal cancer kills some 50,000 deaths per year, making it one of the country's leading causes of cancer death.
"While the disease is generally caused by bad dietary habits and lack of physical activity, it can possibly be prevented by several medications, such as aspirin and cholesterol-lowering medication of the statins group," said Prof. Rennert. "And now, we can add bisphosphonates to the list of tools for potential prevention of colorectal cancer."
NAC can help prevent and treat cancers
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Researchers from Jefferson's Kimmel Cancer Center have genetic evidence suggesting the antioxidant drugs currently used to treat lung disease, malaria and even the common cold can also help prevent and treat cancers because they fight against mitochondrial oxidative stress—a culprit in driving tumor growth.
For the first time, the researchers show that loss of the tumor suppressor protein Caveolin-1 (Cav-1) induces mitochondrial oxidative stress in the stromal micro-environment, a process that fuels cancer cells in most common types of breast cancer.
"Now we have genetic proof that mitochondrial oxidative stress is important for driving tumor growth," said lead researcher Michael P. Lisanti, M.D., Ph.D., professor of cancer biology at Jefferson Medical College of Thomas Jefferson University and member of the Kimmel Cancer Center at Jefferson. "This means we need to make anti-cancer drugs that specially target this type of oxidative stress. And there are already antioxidant drugs out there on the market as dietary supplements, like N-acetyl cysteine (NAC)."
These findings were published in the online February 15 issue of Cancer Biology & Therapy.
Lisanti's lab previously discovered Cav-1 as a biomarker that functions as a tumor suppressor and is the single strongest predictor of breast cancer patient outcome. For example, if a woman has triple negative breast cancer and is Cav-1 positive in the stroma, her survival is greater than 75 percent at 12 years, versus less than 10 percent at 5 years if she doesn't have the Cav-1 protein, according to Dr. Lisanti.
The researchers also established Cav-1's role in oxidative stress and tumor growth; however, where that stress originates and its mechanism(s) were unclear.
To determine this, Jefferson researchers applied a genetically tractable model for human cancer associated fibroblasts in this study using a targeted sh-RNA knock-down approach. Without the Cav-1 protein, researchers found that oxidative stress in cancer associated fibroblasts leads to mitochondrial dysfunction in stromal fibroblasts. In this context, oxidative stress and the resulting autophagy (producton of recycled nutrients) in the tumor-microenvironment function as metabolic energy or "food" to "fuel" tumor growth.
The researchers report that the loss of Cav-1 increases mitochondrial oxidative stress in the tumor stroma, increasing both tumor mass and tumor volume by four-fold, without any increase in tumor angiogenesis.
"Antioxidants have been associated with cancer reducing effects—beta carotene, for example—but the mechanisms, the genetic evidence, has been lacking," Dr. Lisanti said. "This study provides the necessary genetic evidence that reducing oxidative stress in the body will decrease tumor growth."
Currently, anti-cancer drugs targeting oxidative stress are not used because is it commonly thought they will reduce the effectiveness of certain chemotherapies, which increase oxidative stress.
"We are not taking advantage of the available drugs that reduce oxidative stress and autophagy, including metformin, chloroquine and N-acetyl cysteine," Dr. Lisanti said. "Now that we have genetic proof that oxidative stress and resulting autophagy are important for driving tumor growth, we should re-consider using antioxidants and autophagy inhibitors as anti-cancer agents."
The diabetic drug metformin and chloroquine, which is used for the prevention and treatment of malaria, prevent a loss of Cav-1 in cancer associated fibroblasts (which is due to oxidative stress), functionally cutting off the fuel supply to cancer cells.
This research also has important implications for understanding the pathogenesis of triple negative and tamoxifen-resistance in ER-positive breast caner patients, as well as other epithelial cancers, such as prostate cancers.
"Undoubtedly, this new genetically tractable system for cancer associated fibroblasts will help identify other key genetic 'factors' that can block tumor growth," Dr. Lisanti said.
Researchers from Jefferson's Kimmel Cancer Center have genetic evidence suggesting the antioxidant drugs currently used to treat lung disease, malaria and even the common cold can also help prevent and treat cancers because they fight against mitochondrial oxidative stress—a culprit in driving tumor growth.
For the first time, the researchers show that loss of the tumor suppressor protein Caveolin-1 (Cav-1) induces mitochondrial oxidative stress in the stromal micro-environment, a process that fuels cancer cells in most common types of breast cancer.
"Now we have genetic proof that mitochondrial oxidative stress is important for driving tumor growth," said lead researcher Michael P. Lisanti, M.D., Ph.D., professor of cancer biology at Jefferson Medical College of Thomas Jefferson University and member of the Kimmel Cancer Center at Jefferson. "This means we need to make anti-cancer drugs that specially target this type of oxidative stress. And there are already antioxidant drugs out there on the market as dietary supplements, like N-acetyl cysteine (NAC)."
These findings were published in the online February 15 issue of Cancer Biology & Therapy.
Lisanti's lab previously discovered Cav-1 as a biomarker that functions as a tumor suppressor and is the single strongest predictor of breast cancer patient outcome. For example, if a woman has triple negative breast cancer and is Cav-1 positive in the stroma, her survival is greater than 75 percent at 12 years, versus less than 10 percent at 5 years if she doesn't have the Cav-1 protein, according to Dr. Lisanti.
The researchers also established Cav-1's role in oxidative stress and tumor growth; however, where that stress originates and its mechanism(s) were unclear.
To determine this, Jefferson researchers applied a genetically tractable model for human cancer associated fibroblasts in this study using a targeted sh-RNA knock-down approach. Without the Cav-1 protein, researchers found that oxidative stress in cancer associated fibroblasts leads to mitochondrial dysfunction in stromal fibroblasts. In this context, oxidative stress and the resulting autophagy (producton of recycled nutrients) in the tumor-microenvironment function as metabolic energy or "food" to "fuel" tumor growth.
The researchers report that the loss of Cav-1 increases mitochondrial oxidative stress in the tumor stroma, increasing both tumor mass and tumor volume by four-fold, without any increase in tumor angiogenesis.
"Antioxidants have been associated with cancer reducing effects—beta carotene, for example—but the mechanisms, the genetic evidence, has been lacking," Dr. Lisanti said. "This study provides the necessary genetic evidence that reducing oxidative stress in the body will decrease tumor growth."
Currently, anti-cancer drugs targeting oxidative stress are not used because is it commonly thought they will reduce the effectiveness of certain chemotherapies, which increase oxidative stress.
"We are not taking advantage of the available drugs that reduce oxidative stress and autophagy, including metformin, chloroquine and N-acetyl cysteine," Dr. Lisanti said. "Now that we have genetic proof that oxidative stress and resulting autophagy are important for driving tumor growth, we should re-consider using antioxidants and autophagy inhibitors as anti-cancer agents."
The diabetic drug metformin and chloroquine, which is used for the prevention and treatment of malaria, prevent a loss of Cav-1 in cancer associated fibroblasts (which is due to oxidative stress), functionally cutting off the fuel supply to cancer cells.
This research also has important implications for understanding the pathogenesis of triple negative and tamoxifen-resistance in ER-positive breast caner patients, as well as other epithelial cancers, such as prostate cancers.
"Undoubtedly, this new genetically tractable system for cancer associated fibroblasts will help identify other key genetic 'factors' that can block tumor growth," Dr. Lisanti said.
Zinc reduces the burden of the common cold
Ω
Zinc supplements reduce the severity and duration of illness caused by the common cold, according to a systematic review published in The Cochrane Library. The findings could help reduce the amount of time lost from work and school due to colds.
The common cold places a heavy burden on society, accounting for approximately 40% of time taken off work and millions of days of school missed by children each year. The idea that zinc might be effective against the common cold came from a study carried out in 1984, which showed that zinc lozenges could reduce how long symptoms lasted. Since then, trials have produced conflicting results and although several biological explanations for the effect have been proposed, none have been confirmed.
The review updates a previous Cochrane Systematic Review, carried out in 1999, with data from several new trials. In total, data from 15 trials, involving 1,360 people, were included. According to the results, zinc syrup, lozenges or tablets taken within a day of the onset of cold symptoms reduce the severity and length of illness. At seven days, more of the patients who took zinc had cleared their symptoms compared to those who took placebos. Children who took zinc syrup or lozenges for five months or longer caught fewer colds and took less time off school. Zinc also reduced antibiotic use in children, which is important because overuse has implications for antibiotic resistance.
"This review strengthens the evidence for zinc as a treatment for the common cold," said lead researcher Meenu Singh of the Post Graduate Institute of Medical Education and Research in Chandigarh, India. "However, at the moment, it is still difficult to make a general recommendation, because we do not know very much about the optimum dose, formulation or length of treatment."
Further research should focus on the benefits of zinc in defined populations, the review suggests. "Our review only looked at zinc supplementation in healthy people," said Singh. "But it would be interesting to find out whether zinc supplementation could help asthmatics, whose asthma symptoms tend to get worse when they catch a cold." The researchers also say that more work needs to be carried out in low-income countries, where zinc deficiency may be prevalent.
Zinc supplements reduce the severity and duration of illness caused by the common cold, according to a systematic review published in The Cochrane Library. The findings could help reduce the amount of time lost from work and school due to colds.
The common cold places a heavy burden on society, accounting for approximately 40% of time taken off work and millions of days of school missed by children each year. The idea that zinc might be effective against the common cold came from a study carried out in 1984, which showed that zinc lozenges could reduce how long symptoms lasted. Since then, trials have produced conflicting results and although several biological explanations for the effect have been proposed, none have been confirmed.
The review updates a previous Cochrane Systematic Review, carried out in 1999, with data from several new trials. In total, data from 15 trials, involving 1,360 people, were included. According to the results, zinc syrup, lozenges or tablets taken within a day of the onset of cold symptoms reduce the severity and length of illness. At seven days, more of the patients who took zinc had cleared their symptoms compared to those who took placebos. Children who took zinc syrup or lozenges for five months or longer caught fewer colds and took less time off school. Zinc also reduced antibiotic use in children, which is important because overuse has implications for antibiotic resistance.
"This review strengthens the evidence for zinc as a treatment for the common cold," said lead researcher Meenu Singh of the Post Graduate Institute of Medical Education and Research in Chandigarh, India. "However, at the moment, it is still difficult to make a general recommendation, because we do not know very much about the optimum dose, formulation or length of treatment."
Further research should focus on the benefits of zinc in defined populations, the review suggests. "Our review only looked at zinc supplementation in healthy people," said Singh. "But it would be interesting to find out whether zinc supplementation could help asthmatics, whose asthma symptoms tend to get worse when they catch a cold." The researchers also say that more work needs to be carried out in low-income countries, where zinc deficiency may be prevalent.
Good Diets Fight Bad Alzheimer Genes
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Diets high in fish oil have a beneficial effect in patients at risk
Scientists today agree that there are five molecules that are known to affect or cause Alzheimer's disease, which plagues an estimated five million Americans. The potency of these molecules is linked to environmental factors such as diet and lifestyle.
Prof. Daniel Michaelson of Tel Aviv University's Department of Neurobiology at the George S. Wise Faculty of Life Sciences has illuminating news about one of these five molecules — APOE, created by the apolipoprotein E. gene found in all of our bodies.
Prof. Michaelson says APOE comes in two forms, a "good" APOE gene and a "bad" APOE gene, called APOE4. He has developed animal models to investigate the effects of diet and environment on carriers of APOE4, the presence of which is a known risk factor for Alzheimer's. It appears in 50% of all Alzheimer's patients, and in 15% of the general population which due to APOE4 is the population which is at risk of getting the disease.
The good news? In preliminary results, the researchers are exhilarated to find that a diet high in Omega 3 oils and low in cholesterol appears to significantly reduce the negative effects of the APOE4 gene in mouse models.
Exercise is not enough — and may be worse
In differentiating between the good and bad variants of the APOE gene, Prof. Michaelson and his team studied many variables. They determined that while a rich and stimulating environment is good for carriers of "good" APOE, the same environment has a negative effect on those at risk for Alzheimer's because they carry the APOE4 gene. While this environment stimulated the formation of new neuronal connections in the "good APOE" mice, it caused the death of brain neurons in the "bad APOE" mice. The stimulating environment included running wheels and tubes for hiding and sliding, as well as ropes and other toys for the mice to play on, replaced and updated with new toys weekly. Those in a non-stimulating environment had access to no toys at all.
"Conditions that are generally considered good can be harmful if the mouse is a carrier of the APOE4 gene. Extrapolating this to the human population, individuals with the bad APOE4 gene are more susceptible to stress caused by an environment that stimulates their brain," says Prof. Michaelson.
Recently he expanded his original findings, first published in the Journal of Neuroscience in 2008, with a new element: diet.
APOE is a lipoprotein and known to be influenced by the good oil found in fish. Prof. Michaelson and his European colleagues, under a joint European Commission grant called LIPIDIDIET, constructed an experiment. In a standardized environment, they introduced three different kinds of diet: a normal diet, a "bad" diet high in cholesterol, and a "good" diet high in fish oil.
When it's good, it's good
"The main take-away message here is that good diets can alleviate the effects of bad genes. Of course nutritionists have had this general idea for a while, but it's nice to be able to show that this approach can be applied to specifically counteract the negative effects of Alzheimer's disease-related genes," says Prof. Michaelson.
Diets high in fish oil have a beneficial effect in patients at risk
Scientists today agree that there are five molecules that are known to affect or cause Alzheimer's disease, which plagues an estimated five million Americans. The potency of these molecules is linked to environmental factors such as diet and lifestyle.
Prof. Daniel Michaelson of Tel Aviv University's Department of Neurobiology at the George S. Wise Faculty of Life Sciences has illuminating news about one of these five molecules — APOE, created by the apolipoprotein E. gene found in all of our bodies.
Prof. Michaelson says APOE comes in two forms, a "good" APOE gene and a "bad" APOE gene, called APOE4. He has developed animal models to investigate the effects of diet and environment on carriers of APOE4, the presence of which is a known risk factor for Alzheimer's. It appears in 50% of all Alzheimer's patients, and in 15% of the general population which due to APOE4 is the population which is at risk of getting the disease.
The good news? In preliminary results, the researchers are exhilarated to find that a diet high in Omega 3 oils and low in cholesterol appears to significantly reduce the negative effects of the APOE4 gene in mouse models.
Exercise is not enough — and may be worse
In differentiating between the good and bad variants of the APOE gene, Prof. Michaelson and his team studied many variables. They determined that while a rich and stimulating environment is good for carriers of "good" APOE, the same environment has a negative effect on those at risk for Alzheimer's because they carry the APOE4 gene. While this environment stimulated the formation of new neuronal connections in the "good APOE" mice, it caused the death of brain neurons in the "bad APOE" mice. The stimulating environment included running wheels and tubes for hiding and sliding, as well as ropes and other toys for the mice to play on, replaced and updated with new toys weekly. Those in a non-stimulating environment had access to no toys at all.
"Conditions that are generally considered good can be harmful if the mouse is a carrier of the APOE4 gene. Extrapolating this to the human population, individuals with the bad APOE4 gene are more susceptible to stress caused by an environment that stimulates their brain," says Prof. Michaelson.
Recently he expanded his original findings, first published in the Journal of Neuroscience in 2008, with a new element: diet.
APOE is a lipoprotein and known to be influenced by the good oil found in fish. Prof. Michaelson and his European colleagues, under a joint European Commission grant called LIPIDIDIET, constructed an experiment. In a standardized environment, they introduced three different kinds of diet: a normal diet, a "bad" diet high in cholesterol, and a "good" diet high in fish oil.
When it's good, it's good
"The main take-away message here is that good diets can alleviate the effects of bad genes. Of course nutritionists have had this general idea for a while, but it's nice to be able to show that this approach can be applied to specifically counteract the negative effects of Alzheimer's disease-related genes," says Prof. Michaelson.
Monday, February 14, 2011
Fish Oil Protects Against Cardiovascular Disease
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A Michigan Technological University scientist is finding a growing body of evidence suggesting that the omega-3 fatty acids found in fish oil protect against cardiovascular disease.
Fish oil has been shown to improve vascular function (blood flow) by decreasing triglyceride levels and the growth rate of atherosclerotic plaques, and by reducing blood pressure, says Jason R, Carter, chair of the Department of Exercise Science, Health and Physical Education at Michigan Tech. The underlying mechanisms responsible are not entirely clear, but reduction of sympathetic nerve activity (the flight/fight response) may be an important contributor, Carter suggests.
A Michigan Technological University scientist is finding a growing body of evidence suggesting that the omega-3 fatty acids found in fish oil protect against cardiovascular disease.
Fish oil has been shown to improve vascular function (blood flow) by decreasing triglyceride levels and the growth rate of atherosclerotic plaques, and by reducing blood pressure, says Jason R, Carter, chair of the Department of Exercise Science, Health and Physical Education at Michigan Tech. The underlying mechanisms responsible are not entirely clear, but reduction of sympathetic nerve activity (the flight/fight response) may be an important contributor, Carter suggests.
Eating berries may lower risk of Parkinson's
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New research shows men and women who regularly eat berries may have a lower risk of developing Parkinson's disease, while men may also further lower their risk by regularly eating apples, oranges and other sources rich in dietary components called flavonoids. The study was released today and will be presented at the American Academy of Neurology's 63rd Annual Meeting in Honolulu April 9 to April 16, 2011.
Flavonoids are found in plants and fruits and are also known collectively as vitamin P and citrin. They can also be found in berry fruits, chocolate, and citrus fruits such as grapefruit.
The study involved 49,281 men and 80,336 women. Researchers gave participants questionnaires and used a database to calculate intake amount of flavonoids. They then analyzed the association between flavonoid intakes and risk of developing Parkinson's disease. They also analyzed consumption of five major sources of foods rich in flavonoids: tea, berries, apples, red wine and oranges or orange juice. The participants were followed for 20 to 22 years.
During that time, 805 people developed Parkinson's disease. In men, the top 20 percent who consumed the most flavonoids were about 40 percent less likely to develop Parkinson's disease than the bottom 20 percent of male participants who consumed the least amount of flavonoids. In women, there was no relationship between overall flavonoid consumption and developing Parkinson's disease. However, when sub-classes of flavonoids were examined, regular consumption of anthocyanins, which are mainly obtained from berries, were found to be associated with a lower risk of Parkinson's disease in both men and women.
"This is the first study in humans to examine the association between flavonoids and risk of developing Parkinson's disease," said study author Xiang Gao, MD, PhD, with the Harvard School of Public Health in Boston. "Our findings suggest that flavonoids, specifically a group called anthocyanins, may have neuroprotective effects. If confirmed, flavonoids may be a natural and healthy way to reduce your risk of developing Parkinson's disease."
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New research shows men and women who regularly eat berries may have a lower risk of developing Parkinson's disease, while men may also further lower their risk by regularly eating apples, oranges and other sources rich in dietary components called flavonoids. The study was released today and will be presented at the American Academy of Neurology's 63rd Annual Meeting in Honolulu April 9 to April 16, 2011.
Flavonoids are found in plants and fruits and are also known collectively as vitamin P and citrin. They can also be found in berry fruits, chocolate, and citrus fruits such as grapefruit.
The study involved 49,281 men and 80,336 women. Researchers gave participants questionnaires and used a database to calculate intake amount of flavonoids. They then analyzed the association between flavonoid intakes and risk of developing Parkinson's disease. They also analyzed consumption of five major sources of foods rich in flavonoids: tea, berries, apples, red wine and oranges or orange juice. The participants were followed for 20 to 22 years.
During that time, 805 people developed Parkinson's disease. In men, the top 20 percent who consumed the most flavonoids were about 40 percent less likely to develop Parkinson's disease than the bottom 20 percent of male participants who consumed the least amount of flavonoids. In women, there was no relationship between overall flavonoid consumption and developing Parkinson's disease. However, when sub-classes of flavonoids were examined, regular consumption of anthocyanins, which are mainly obtained from berries, were found to be associated with a lower risk of Parkinson's disease in both men and women.
"This is the first study in humans to examine the association between flavonoids and risk of developing Parkinson's disease," said study author Xiang Gao, MD, PhD, with the Harvard School of Public Health in Boston. "Our findings suggest that flavonoids, specifically a group called anthocyanins, may have neuroprotective effects. If confirmed, flavonoids may be a natural and healthy way to reduce your risk of developing Parkinson's disease."
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Fiber intake associated with reduced risk of death
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Dietary fiber may be associated with a reduced risk of death from cardiovascular, infectious and respiratory diseases, as well as a reduced risk of death from any cause over a nine-year period, according to a report posted online today that will be published in the June 14 print issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Fiber, the edible part of plants that resist digestion, has been hypothesized to lower risks of heart disease, some cancers, diabetes and obesity, according to background information in the article. It is known to assist with bowel movements, reduce blood cholesterol levels, improve blood glucose levels, lower blood pressure, promote weight loss and reduce inflammation and bind to potential cancer-causing agents to increase the likelihood they will be excreted by the body.
Yikyung Park, Sc.D., of the National Cancer Institute, Rockville, Md., and colleagues analyzed data from 219,123 men and 168,999 women in the National Institutes of Health-AARP Diet and Health Study. Participants completed a food frequency questionnaire at the beginning of the study in 1995 and 1996. Causes of death were determined by linking study records to national registries.
Participants' fiber intake ranged from 13 to 29 grams per day in men and from 11 to 26 grams per day in women. Over an average of nine years of follow-up, 20,126 men and 11,330 women died. Fiber intake was associated with a significantly decreased risk of total death in both men and women—the one-fifth of men and women consuming the most fiber (29.4 grams per day for men and 25.8 grams for women) were 22 percent less likely to die than those consuming the least (12.6 grams per day for men and 10.8 grams for women).
The risk of cardiovascular, infectious and respiratory diseases was reduced by 24 percent to 56 percent in men and 34 percent to 59 percent in women with high fiber intakes. Dietary fiber from grains, but not from other sources such as fruits, was associated with reduced risks of total, cardiovascular, cancer and respiratory disease deaths in men and women.
"The findings remained robust when we corrected for dietary intake measurement error using calibration study data; in fact, the association was even stronger with measurement error correction," the authors write.
"The current Dietary Guidelines for Americans recommend choosing fiber-rich fruits, vegetables and whole grains frequently and consuming 14 grams per 1,000 calories of dietary fiber," the authors conclude. "A diet rich in dietary fiber from whole plant foods may provide significant health benefits."
Dietary fiber may be associated with a reduced risk of death from cardiovascular, infectious and respiratory diseases, as well as a reduced risk of death from any cause over a nine-year period, according to a report posted online today that will be published in the June 14 print issue of Archives of Internal Medicine, one of the JAMA/Archives journals.
Fiber, the edible part of plants that resist digestion, has been hypothesized to lower risks of heart disease, some cancers, diabetes and obesity, according to background information in the article. It is known to assist with bowel movements, reduce blood cholesterol levels, improve blood glucose levels, lower blood pressure, promote weight loss and reduce inflammation and bind to potential cancer-causing agents to increase the likelihood they will be excreted by the body.
Yikyung Park, Sc.D., of the National Cancer Institute, Rockville, Md., and colleagues analyzed data from 219,123 men and 168,999 women in the National Institutes of Health-AARP Diet and Health Study. Participants completed a food frequency questionnaire at the beginning of the study in 1995 and 1996. Causes of death were determined by linking study records to national registries.
Participants' fiber intake ranged from 13 to 29 grams per day in men and from 11 to 26 grams per day in women. Over an average of nine years of follow-up, 20,126 men and 11,330 women died. Fiber intake was associated with a significantly decreased risk of total death in both men and women—the one-fifth of men and women consuming the most fiber (29.4 grams per day for men and 25.8 grams for women) were 22 percent less likely to die than those consuming the least (12.6 grams per day for men and 10.8 grams for women).
The risk of cardiovascular, infectious and respiratory diseases was reduced by 24 percent to 56 percent in men and 34 percent to 59 percent in women with high fiber intakes. Dietary fiber from grains, but not from other sources such as fruits, was associated with reduced risks of total, cardiovascular, cancer and respiratory disease deaths in men and women.
"The findings remained robust when we corrected for dietary intake measurement error using calibration study data; in fact, the association was even stronger with measurement error correction," the authors write.
"The current Dietary Guidelines for Americans recommend choosing fiber-rich fruits, vegetables and whole grains frequently and consuming 14 grams per 1,000 calories of dietary fiber," the authors conclude. "A diet rich in dietary fiber from whole plant foods may provide significant health benefits."
Thursday, February 10, 2011
Study related to diet soda and stroke risk is seriously flawed
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Study is drawing a growing body of criticism and skepticism from experts in the field of nutrition and science
The Calorie Control Council stated today that research findings presented during a poster session at the International Stroke Conference claiming an association between diet soft drink consumption and increased risk of stroke and heart attack are critically flawed.
"The findings are so speculative and preliminary at this point that they should be considered with extreme caution. In fact, the study has not been peer reviewed by any independent scientists and has not been published in a scientific journal," stated Beth Hubrich, a registered dietitian with the Council.
The research, as well as the publicity regarding the study abstract, is drawing a growing body of criticism and skepticism from experts in the field of nutrition and science.
"I have to say this is one of the worst studies I've seen capturing headlines in a long time," said Dr. Richard Besser, Chief Health and Medical Editor at ABC News, commenting during a February 10 segment on Good Morning America. "It's bad because of the science, but it's also bad because of the behavior that it can induce and the fear that people have. I don't think people should change behavior based on this study."
Pointing out some of the flaws in the study, Besser added, "They didn't look at how much salt they took in, they didn't look at what other foods they ate. Those things we know are associated with stroke and heart attack. They didn't even look at obesity over time. And so to conclude from this, that it's all from the diet soda, just makes no sense whatsoever."
Dr. Walter Willett, chair of the Department of Nutrition at Harvard School of Public Health, echoed this criticism in comments presented on ABCnews.com (http://abcnews.go.com/Health/video/taking-diet-soda-study-grain-salt-12870775): "It's important to keep in mind that his was really a preliminary report. It's not even published yet, and the study was fairly small. I think we have to interpret the findings about diet soda very carefully, in almost any first report, we shouldn't really change our behavior, because it could easily have occurred by chance."
The poster presentation is also at odds with statements on the website of the American Heart Association, sponsor of the conference where this poster was presented. Regarding the low-calorie sweeteners used in diet soft drinks, AHA states: "Try non-nutritive sweeteners such as aspartame, sucralose or saccharin in moderation. Non-nutritive sweeteners may be a way to satisfy your sweet tooth without adding more calories to your diet. The FDA has determined that non-nutritive sweeteners are safe."
Among the weaknesses and criticisms of the poster:
The poster is not a published study and has not been peer-reviewed for a scientific journal. As a result, it has not been examined by experts as to design, reasonableness of conclusions, and other methodological issues. The academic standards for poster presentations are lower than for peer-reviewed scientific journals, calling the conclusions into greater question.
The soda intake data used for this presentation are of questionable reliability. They are based on self-reported consumption figures, which are grouped into general categories, such as "moderate diet only" soda consumers. This imprecision makes it very difficult to draw any meaningful conclusions from the study.
This study is observational and does not show cause and effect. As a result, the presenters' conclusion that diet soda "may be associated with a greater risk of stroke, MI or vascular death than regular soda" is not well founded. For example, the authors do not appear to have controlled for such critical factors as family history of heart disease or stroke, or for weight gain. Also, stroke is more common in men 55 years of age and older and women 65 years or older. The average age of those in the study was 69.
The sample size of those who claimed they drank diet soda daily was small – only 4.5 percent of the total study sample.
The overall study population was not representative of the U.S. population, either in age (average age was 69), or race (only 20 percent non-Hispanic white).
Cardiovascular events are very complex statistically. Many people who have had a cardiovascular event (and therefore are a much higher risk for a second, statistically) are switched to a low calorie diet which will often include diet drinks as opposed to high calorie drinks.
The authors offer no explanation or theories for why diet soft drinks might be related to an increased risk of vascular events.
Low-calorie sweeteners are some of the most thoroughly studied food ingredients in the food supply. The safety of low-calorie sweeteners has been reaffirmed time and again by leading health and regulatory groups worldwide.
Study is drawing a growing body of criticism and skepticism from experts in the field of nutrition and science
The Calorie Control Council stated today that research findings presented during a poster session at the International Stroke Conference claiming an association between diet soft drink consumption and increased risk of stroke and heart attack are critically flawed.
"The findings are so speculative and preliminary at this point that they should be considered with extreme caution. In fact, the study has not been peer reviewed by any independent scientists and has not been published in a scientific journal," stated Beth Hubrich, a registered dietitian with the Council.
The research, as well as the publicity regarding the study abstract, is drawing a growing body of criticism and skepticism from experts in the field of nutrition and science.
"I have to say this is one of the worst studies I've seen capturing headlines in a long time," said Dr. Richard Besser, Chief Health and Medical Editor at ABC News, commenting during a February 10 segment on Good Morning America. "It's bad because of the science, but it's also bad because of the behavior that it can induce and the fear that people have. I don't think people should change behavior based on this study."
Pointing out some of the flaws in the study, Besser added, "They didn't look at how much salt they took in, they didn't look at what other foods they ate. Those things we know are associated with stroke and heart attack. They didn't even look at obesity over time. And so to conclude from this, that it's all from the diet soda, just makes no sense whatsoever."
Dr. Walter Willett, chair of the Department of Nutrition at Harvard School of Public Health, echoed this criticism in comments presented on ABCnews.com (http://abcnews.go.com/Health/video/taking-diet-soda-study-grain-salt-12870775): "It's important to keep in mind that his was really a preliminary report. It's not even published yet, and the study was fairly small. I think we have to interpret the findings about diet soda very carefully, in almost any first report, we shouldn't really change our behavior, because it could easily have occurred by chance."
The poster presentation is also at odds with statements on the website of the American Heart Association, sponsor of the conference where this poster was presented. Regarding the low-calorie sweeteners used in diet soft drinks, AHA states: "Try non-nutritive sweeteners such as aspartame, sucralose or saccharin in moderation. Non-nutritive sweeteners may be a way to satisfy your sweet tooth without adding more calories to your diet. The FDA has determined that non-nutritive sweeteners are safe."
Among the weaknesses and criticisms of the poster:
The poster is not a published study and has not been peer-reviewed for a scientific journal. As a result, it has not been examined by experts as to design, reasonableness of conclusions, and other methodological issues. The academic standards for poster presentations are lower than for peer-reviewed scientific journals, calling the conclusions into greater question.
The soda intake data used for this presentation are of questionable reliability. They are based on self-reported consumption figures, which are grouped into general categories, such as "moderate diet only" soda consumers. This imprecision makes it very difficult to draw any meaningful conclusions from the study.
This study is observational and does not show cause and effect. As a result, the presenters' conclusion that diet soda "may be associated with a greater risk of stroke, MI or vascular death than regular soda" is not well founded. For example, the authors do not appear to have controlled for such critical factors as family history of heart disease or stroke, or for weight gain. Also, stroke is more common in men 55 years of age and older and women 65 years or older. The average age of those in the study was 69.
The sample size of those who claimed they drank diet soda daily was small – only 4.5 percent of the total study sample.
The overall study population was not representative of the U.S. population, either in age (average age was 69), or race (only 20 percent non-Hispanic white).
Cardiovascular events are very complex statistically. Many people who have had a cardiovascular event (and therefore are a much higher risk for a second, statistically) are switched to a low calorie diet which will often include diet drinks as opposed to high calorie drinks.
The authors offer no explanation or theories for why diet soft drinks might be related to an increased risk of vascular events.
Low-calorie sweeteners are some of the most thoroughly studied food ingredients in the food supply. The safety of low-calorie sweeteners has been reaffirmed time and again by leading health and regulatory groups worldwide.
Wednesday, February 9, 2011
Diet soda may raise odds of vascular events; salt linked to stroke risk
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Even if you drink diet soda — instead of the sugar variety — you could still have a much higher risk of vascular events compared to those who don't drink soda, according to research presented at the American Stroke Association's International Stroke Conference 2011.
In findings involving 2,564 people in the large, multi-ethnic Northern Manhattan Study (NOMAS), scientists said people who drank diet soda every day had a 61 percent higher risk of vascular events than those who reported no soda drinking.
"If our results are confirmed with future studies, then it would suggest that diet soda may not be the optimal substitute for sugar-sweetened beverages for protection against vascular outcomes," said Hannah Gardener, Sc.D., lead author and epidemiologist at the University of Miami Miller School of Medicine in Miami, Fla.
In separate research using 2,657 participants also in the Manhattan study, scientists found that high salt intake, independent of the hypertension it causes, was linked to a dramatically increased risk of ischemic strokes (when a blood vessel blockage cuts off blood flow to the brain).
In the study, people who consumed more than 4,000 milligrams (mg) per day of sodium had more than double the risk of stroke compared to those consuming less than 1,500 mg per day.
At the start of both studies, researchers assessed diet by a food frequency questionnaire.
NOMAS is a collaboration of investigators at Columbia University in New York and Miami's Miller School of Medicine, launched in 1993 to examine stroke incidence and risk factors in a multi-ethnic urban population. A total of 3,298 participants over 40 years old (average age 69) were enrolled through 2001 and continue to be followed. Sixty-three percent were women, 21 percent were white, 24 percent black and 53 percent Hispanic.
In the soda study, researchers asked subjects at the outset to report how much and what kind of soda they drank. Based on the data, they grouped participants into seven consumption categories: no soda (meaning less than one soda of any kind per month); moderate regular soda only (between one per month and six per week), daily regular soda (at least one per day); moderate diet soda only; daily diet soda only; and two groups of people who drink both types: moderate diet and any regular, and daily diet with any regular.
During an average follow-up of 9.3 years, 559 vascular events occurred (including ischemic and hemorrhagic stroke, which is caused by rupture of a weakened blood vessel). Researchers accounted for participants' age, sex, race or ethnicity, smoking status, exercise, alcohol consumption and daily caloric intake. And even after researchers also accounted for patients' metabolic syndrome, peripheral vascular disease and heart disease history, the increased risk persisted at a rate 48 percent higher.
In the sodium research, 187 ischemic strokes were reported during 9.7 years of follow-up. Stroke risk, independent of hypertension, increased 16 percent for every 500 mg of sodium consumed a day, the scientists calculated. Those figures included adjustment for age, sex, race/ethnicity, education, alcohol use, exercise, daily caloric intake, smoking status, diabetes, high cholesterol, high blood pressure and previous heart disease.
Only a third of participants met the current U.S. Dietary Guidelines for Americans that recommend daily sodium intake fall below 2,300 mg, or about a teaspoon of salt, Gardener said. Only 12 percent of subjects met the American Heart Association's recommendations to consume less than 1,500 mg a day. Average intake was 3,031 milligrams.
"The take-home message is that high sodium intake is a risk factor for ischemic stroke among people with hypertension as well as among those without hypertension, underscoring the importance of limiting consumption of high sodium foods for stroke prevention," Gardener said.
Participants' reporting their dietary behavior is a key limitation of both studies, Gardener said.
In the soda study, investigators also lacked data on types of diet and regular drinks consumed, preventing analysis of whether variations among brands or changes over time in coloring and sweeteners might have played a role.
Even if you drink diet soda — instead of the sugar variety — you could still have a much higher risk of vascular events compared to those who don't drink soda, according to research presented at the American Stroke Association's International Stroke Conference 2011.
In findings involving 2,564 people in the large, multi-ethnic Northern Manhattan Study (NOMAS), scientists said people who drank diet soda every day had a 61 percent higher risk of vascular events than those who reported no soda drinking.
"If our results are confirmed with future studies, then it would suggest that diet soda may not be the optimal substitute for sugar-sweetened beverages for protection against vascular outcomes," said Hannah Gardener, Sc.D., lead author and epidemiologist at the University of Miami Miller School of Medicine in Miami, Fla.
In separate research using 2,657 participants also in the Manhattan study, scientists found that high salt intake, independent of the hypertension it causes, was linked to a dramatically increased risk of ischemic strokes (when a blood vessel blockage cuts off blood flow to the brain).
In the study, people who consumed more than 4,000 milligrams (mg) per day of sodium had more than double the risk of stroke compared to those consuming less than 1,500 mg per day.
At the start of both studies, researchers assessed diet by a food frequency questionnaire.
NOMAS is a collaboration of investigators at Columbia University in New York and Miami's Miller School of Medicine, launched in 1993 to examine stroke incidence and risk factors in a multi-ethnic urban population. A total of 3,298 participants over 40 years old (average age 69) were enrolled through 2001 and continue to be followed. Sixty-three percent were women, 21 percent were white, 24 percent black and 53 percent Hispanic.
In the soda study, researchers asked subjects at the outset to report how much and what kind of soda they drank. Based on the data, they grouped participants into seven consumption categories: no soda (meaning less than one soda of any kind per month); moderate regular soda only (between one per month and six per week), daily regular soda (at least one per day); moderate diet soda only; daily diet soda only; and two groups of people who drink both types: moderate diet and any regular, and daily diet with any regular.
During an average follow-up of 9.3 years, 559 vascular events occurred (including ischemic and hemorrhagic stroke, which is caused by rupture of a weakened blood vessel). Researchers accounted for participants' age, sex, race or ethnicity, smoking status, exercise, alcohol consumption and daily caloric intake. And even after researchers also accounted for patients' metabolic syndrome, peripheral vascular disease and heart disease history, the increased risk persisted at a rate 48 percent higher.
In the sodium research, 187 ischemic strokes were reported during 9.7 years of follow-up. Stroke risk, independent of hypertension, increased 16 percent for every 500 mg of sodium consumed a day, the scientists calculated. Those figures included adjustment for age, sex, race/ethnicity, education, alcohol use, exercise, daily caloric intake, smoking status, diabetes, high cholesterol, high blood pressure and previous heart disease.
Only a third of participants met the current U.S. Dietary Guidelines for Americans that recommend daily sodium intake fall below 2,300 mg, or about a teaspoon of salt, Gardener said. Only 12 percent of subjects met the American Heart Association's recommendations to consume less than 1,500 mg a day. Average intake was 3,031 milligrams.
"The take-home message is that high sodium intake is a risk factor for ischemic stroke among people with hypertension as well as among those without hypertension, underscoring the importance of limiting consumption of high sodium foods for stroke prevention," Gardener said.
Participants' reporting their dietary behavior is a key limitation of both studies, Gardener said.
In the soda study, investigators also lacked data on types of diet and regular drinks consumed, preventing analysis of whether variations among brands or changes over time in coloring and sweeteners might have played a role.
Omega 3's prevent several forms of blindness
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Omega-3 fatty acids –fats commonly found in fish oil – were shown several years ago to prevent retinopathy, a major form of blindness, in a mouse model of the disease. A follow-up study, from the same research team at Children's Hospital Boston, now reveals exactly how omega-3's provide protection, and provides reassurance that widely used COX-inhibiting drugs like aspirin and NSAIDs don't negate their benefit. The findings, published in the February 9th issue of Science Translational Medicine, also suggest that omega-3's may be beneficial in diabetes.
Retinopathy – an eye disease caused by the proliferation of tortuous, leaky blood vessels in the retina – is a leading cause of blindness, affecting 4.1 million Americans with diabetes (a number expected to double over the next 15 years) and many premature infants. Another 7 million-plus Americans have age-related macular degeneration (AMD); this too will increase as the population ages. The most common "wet" form of AMD is also caused by abnormal blood vessel growth.
The ability to prevent these "neovascular" eye diseases with omega-3 fatty acids could provide tremendous cost savings, says Children's ophthalmologist Lois Smith, MD, PhD, senior investigator on the study. "The cost of omega-3 supplementation is about $10 a month, versus up to $4,000 a month for anti-VEGF therapy," she says, referring to drugs such as Macugen and Lucentis used in AMD and diabetic retinopathy. "Our new findings give us new information on how omega-3s work that makes them an even more promising option."
Omega-3 fatty acids, highly concentrated in the retina, are often lacking in Western diets, which tend to be higher in omega-6 fatty acids. In Smith's previous study (http://www.childrenshospital.org/newsroom/Site1339/mainpageS1339P1sublevel309.html), mice fed diets rich in omega-3 fatty acids by Smith's team had nearly 50 percent less pathologic vessel growth in the retina than mice fed omega-6-rich diets. Smith and colleagues further showed that the omega-3 diet decreased inflammatory messaging in the eye.
In the new study, they document another protective mechanism: a direct effect on blood vessel growth (angiogenesis) that selectively promotes the growth of healthy blood vessels and inhibits the growth of abnormal vessels.
In addition, Smith and colleagues isolated the specific compound from omega-3 fatty acids that has these beneficial effects in mice (a metabolite of the omega-3 fatty acid DHA, known as 4-HDHA), and the enzyme that produces it (5-lipoxygenase, or 5-LOX). They showed that COX enzymes are not involved in omega-3 breakdown, suggesting that aspirin and NSAIDs – taken by millions of Americans -- will not interfere with omega-3 benefits.
"This is important for people with diabetes, who often take aspirin to prevent heart disease, and also for elderly people with AMD who have a propensity for heart disease," says Smith. (One drug used for asthma, zileuton, does interfere with 5-LOX, however.)
Finally, the study demonstrated that 5-LOX acts by activating the PPAR-gamma receptor, the same receptor targeted by "glitazone" drugs such as Avandia, taken by patients with type 2 diabetes to increase their sensitivity to insulin. Since these drugs also increase the risk for heart disease, boosting omega-3 intake through diet or supplements might be a safer way to improve insulin sensitivity in patients with diabetes or pre-diabetes. "There needs to be a good clinical study in diabetes," Smith says.
Smith works closely with principal investigators at the National Eye Institute who are conducting an ongoing multicenter trial of omega-3 supplements in patients with AMD, known as AREDS2. The trial will continue until 2013. An earlier retrospective study, AREDS1, found higher self-reported intake of fish to be associated with a lower likelihood of AMD.
In addition, Smith is collaborating with a group in Sweden that is conducting a clinical trial of omega-3 fatty acids in premature infants, who are often deficient in omega-3. That study will measure infants' blood levels of omega-3 products and follow the infants to see if they develop retinopathy. If results are promising Smith will seek FDA approval to conduct a clinical trial in premature infants at Children's.
Meanwhile, in her lab work, Smith plans to continue seeking beneficial lipid pathways, while looking for the most harmful omega 6 metabolites. "We found the good guys, now we'll look for the bad ones," says Smith. "If we find the pathways, maybe we can selectively block the bad metabolites. We would hope to start with drugs that are already available."
Omega-3 fatty acids –fats commonly found in fish oil – were shown several years ago to prevent retinopathy, a major form of blindness, in a mouse model of the disease. A follow-up study, from the same research team at Children's Hospital Boston, now reveals exactly how omega-3's provide protection, and provides reassurance that widely used COX-inhibiting drugs like aspirin and NSAIDs don't negate their benefit. The findings, published in the February 9th issue of Science Translational Medicine, also suggest that omega-3's may be beneficial in diabetes.
Retinopathy – an eye disease caused by the proliferation of tortuous, leaky blood vessels in the retina – is a leading cause of blindness, affecting 4.1 million Americans with diabetes (a number expected to double over the next 15 years) and many premature infants. Another 7 million-plus Americans have age-related macular degeneration (AMD); this too will increase as the population ages. The most common "wet" form of AMD is also caused by abnormal blood vessel growth.
The ability to prevent these "neovascular" eye diseases with omega-3 fatty acids could provide tremendous cost savings, says Children's ophthalmologist Lois Smith, MD, PhD, senior investigator on the study. "The cost of omega-3 supplementation is about $10 a month, versus up to $4,000 a month for anti-VEGF therapy," she says, referring to drugs such as Macugen and Lucentis used in AMD and diabetic retinopathy. "Our new findings give us new information on how omega-3s work that makes them an even more promising option."
Omega-3 fatty acids, highly concentrated in the retina, are often lacking in Western diets, which tend to be higher in omega-6 fatty acids. In Smith's previous study (http://www.childrenshospital.org/newsroom/Site1339/mainpageS1339P1sublevel309.html), mice fed diets rich in omega-3 fatty acids by Smith's team had nearly 50 percent less pathologic vessel growth in the retina than mice fed omega-6-rich diets. Smith and colleagues further showed that the omega-3 diet decreased inflammatory messaging in the eye.
In the new study, they document another protective mechanism: a direct effect on blood vessel growth (angiogenesis) that selectively promotes the growth of healthy blood vessels and inhibits the growth of abnormal vessels.
In addition, Smith and colleagues isolated the specific compound from omega-3 fatty acids that has these beneficial effects in mice (a metabolite of the omega-3 fatty acid DHA, known as 4-HDHA), and the enzyme that produces it (5-lipoxygenase, or 5-LOX). They showed that COX enzymes are not involved in omega-3 breakdown, suggesting that aspirin and NSAIDs – taken by millions of Americans -- will not interfere with omega-3 benefits.
"This is important for people with diabetes, who often take aspirin to prevent heart disease, and also for elderly people with AMD who have a propensity for heart disease," says Smith. (One drug used for asthma, zileuton, does interfere with 5-LOX, however.)
Finally, the study demonstrated that 5-LOX acts by activating the PPAR-gamma receptor, the same receptor targeted by "glitazone" drugs such as Avandia, taken by patients with type 2 diabetes to increase their sensitivity to insulin. Since these drugs also increase the risk for heart disease, boosting omega-3 intake through diet or supplements might be a safer way to improve insulin sensitivity in patients with diabetes or pre-diabetes. "There needs to be a good clinical study in diabetes," Smith says.
Smith works closely with principal investigators at the National Eye Institute who are conducting an ongoing multicenter trial of omega-3 supplements in patients with AMD, known as AREDS2. The trial will continue until 2013. An earlier retrospective study, AREDS1, found higher self-reported intake of fish to be associated with a lower likelihood of AMD.
In addition, Smith is collaborating with a group in Sweden that is conducting a clinical trial of omega-3 fatty acids in premature infants, who are often deficient in omega-3. That study will measure infants' blood levels of omega-3 products and follow the infants to see if they develop retinopathy. If results are promising Smith will seek FDA approval to conduct a clinical trial in premature infants at Children's.
Meanwhile, in her lab work, Smith plans to continue seeking beneficial lipid pathways, while looking for the most harmful omega 6 metabolites. "We found the good guys, now we'll look for the bad ones," says Smith. "If we find the pathways, maybe we can selectively block the bad metabolites. We would hope to start with drugs that are already available."
Jon's Health Tips - Latest Health Research
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I try not to let reports like this discourage me: (And I keep taking statins and Vitamin D):
Why Almost Everything You Hear About Medicine Is Wrong
Statins should be prescribed with caution in those at low risk of cardiovascular disease
But there is reason to go on:
Vitamin E may increase the life expectancy of older men
Sun exposure, vitamin D may lower risk of multiple sclerosis
Inaccurate Negative Statin News Reports
I can’t wait to resume regular aspirin use.
I try to avoid loneliness: Loneliness is bad for your health
I am eating small amounts of dark chocolate every day:
Dark chocolate and cocoa have a greater antioxidant capacity and a greater total flavanol, and polyphenol, content than the fruit juices
New explanation for heart-healthy benefits of chocolate
I do go to sleep earlier than I used to, and often get a good night’s sleep:
Late nights can lead to higher risk of strokes and heart attacks
Lack of sleep found to be a new risk factor for colon cancer
I certainly prefer to get my exercise outdoors (although not in this weather) but I’m not sure an artificial turf field would qualify:
There are benefits to mental and physical well-being from taking exercise in the natural environment.
Where once I hoped to qualify for stain treatment, now I may want to be treated for osteoporosis :
Australian clinical researchers have noted an extraordinary and unexpected benefit of osteoporosis treatment – that people taking bisphosphonates are not only surviving well, better than people without osteoporosis, they appear to be gaining an extra five years of life.
I’m going to take a break before I continue working on this:
Plenty of breaks, even if they are as little as one minute, seem to be good for people's hearts and their waistlines
I’m eating more vegetables these days (a restaurant with a salad bar near my new office is a big factor) which has many benefits:
Eating More Fruit and Vegetables Is Linked to a Lower Risk of Dying from Ischemic Heart Disease
I am happy that I continue to eat fish, and olive oil, avoid trans-fats, and take Omega-3 oil pills:
A deficiency of dietary omega-3 may explain depressive behaviors
Trans-Fats Increase Risk of Depression, While Olive Oil Helps Avoid Risk
I'm positive that Positive Emotions ARE Good for Your Health.
Olive Oil's Healthy Pain
I continue to drink red wine, which should help me fight aging.
Maybe it’s a good thing the Giants were not in the Super Bowl:
Super Bowl losses can increase cardiac death
Ω
I try not to let reports like this discourage me: (And I keep taking statins and Vitamin D):
Why Almost Everything You Hear About Medicine Is Wrong
In just the last two months, two pillars of preventive medicine fell. A major study concluded there’s no good evidence that statins (drugs like Lipitor and Crestor) help people with no history of heart disease. The study was based on an evaluation of 14 individual trials with 34,272 patients. Cost of statins: more than $20 billion per year, of which half may be unnecessary. In November a panel of the Institute of Medicine concluded that having a blood test for vitamin D is pointless: almost everyone has enough D for bone health (20 nanograms per milliliter) without taking supplements or calcium pills. Cost of vitamin D: $425 million per year...
Statins should be prescribed with caution in those at low risk of cardiovascular disease
But there is reason to go on:
Vitamin E may increase the life expectancy of older men
Sun exposure, vitamin D may lower risk of multiple sclerosis
Inaccurate Negative Statin News Reports
But this is lousy reporting - the actual research conclusion is: "All cause mortality. coronary heart disease and stroke events were reduced with the use of statins....Taking statins did not increase the risk of adverse effects such as cancer." No mention of undesirable side-effects. The researchers mainly criticized the quality of the research, and advised exercising caution.
I can’t wait to resume regular aspirin use.
I try to avoid loneliness: Loneliness is bad for your health
I am eating small amounts of dark chocolate every day:
Dark chocolate and cocoa have a greater antioxidant capacity and a greater total flavanol, and polyphenol, content than the fruit juices
New explanation for heart-healthy benefits of chocolate
I do go to sleep earlier than I used to, and often get a good night’s sleep:
Late nights can lead to higher risk of strokes and heart attacks
Lack of sleep found to be a new risk factor for colon cancer
I certainly prefer to get my exercise outdoors (although not in this weather) but I’m not sure an artificial turf field would qualify:
There are benefits to mental and physical well-being from taking exercise in the natural environment.
Where once I hoped to qualify for stain treatment, now I may want to be treated for osteoporosis :
Australian clinical researchers have noted an extraordinary and unexpected benefit of osteoporosis treatment – that people taking bisphosphonates are not only surviving well, better than people without osteoporosis, they appear to be gaining an extra five years of life.
I’m going to take a break before I continue working on this:
Plenty of breaks, even if they are as little as one minute, seem to be good for people's hearts and their waistlines
I’m eating more vegetables these days (a restaurant with a salad bar near my new office is a big factor) which has many benefits:
Nitrate (found in leafy green vegetables) reduces the blood pressure of healthy individuals and that in laboratory animals it counteracts components of the metabolic syndrome, a pre-stage of diabetes. Other scientists have demonstrated protective effects of nitrate and nitrite in animal models against heart attack and stroke.
Eating More Fruit and Vegetables Is Linked to a Lower Risk of Dying from Ischemic Heart Disease
I am happy that I continue to eat fish, and olive oil, avoid trans-fats, and take Omega-3 oil pills:
A deficiency of dietary omega-3 may explain depressive behaviors
Trans-Fats Increase Risk of Depression, While Olive Oil Helps Avoid Risk
I'm positive that Positive Emotions ARE Good for Your Health.
Olive Oil's Healthy Pain
I continue to drink red wine, which should help me fight aging.
Maybe it’s a good thing the Giants were not in the Super Bowl:
Super Bowl losses can increase cardiac death
Ω
Folic Acid Works Like Aspirin To Prevent a Heart Attack
Ω
A perplexing medical paradox now has an explanation according to research undertaken at Barts and The London School of Medicine and Dentistry and published in the current issue of the Public Library of Science. The paradox is that taking folic acid, a B vitamin, lowers homocysteine in the blood which, epidemiological evidence indicates, should lower the risk of heart attack, but clinical trials of folic acid have not shown the expected benefit.
The explanation is surprisingly simple; lowering homocysteine prevents platelets sticking, which stops blood clots…something aspirin also does, so if people in the trials were already taking aspirin there would be no extra benefit in lowering homocysteine with folic acid. Aspirin was in fact widely used by participants in the trials because they were mainly conducted in patients who had already had a heart attack or other cardiovascular diseases.
Research led by Dr David Wald at the Wolfson Institute of Preventive Medicine at Barts and The London School of Medicine and Dentistry showed that there was a difference in the reduction in heart disease events between the five trials with the lowest aspirin use (60 per cent of the participants took aspirin) and the five trials with the highest use (91 per cent took aspirin). The observed risk reduction was six per cent but it would have been 15 per cent if no one had been taking aspirin. Research was based on 75 epidemiological studies involving about 50,000 participants and clinical trials involving about 40,000 participants.
"The explanation has important implications," said Dr David Wald, the lead author of the paper. "The negative clinical trial evidence should not close the door on folic acid -- folic acid may still be of benefit in people who have not had a heart attack because they will generally not be taking aspirin."
A perplexing medical paradox now has an explanation according to research undertaken at Barts and The London School of Medicine and Dentistry and published in the current issue of the Public Library of Science. The paradox is that taking folic acid, a B vitamin, lowers homocysteine in the blood which, epidemiological evidence indicates, should lower the risk of heart attack, but clinical trials of folic acid have not shown the expected benefit.
The explanation is surprisingly simple; lowering homocysteine prevents platelets sticking, which stops blood clots…something aspirin also does, so if people in the trials were already taking aspirin there would be no extra benefit in lowering homocysteine with folic acid. Aspirin was in fact widely used by participants in the trials because they were mainly conducted in patients who had already had a heart attack or other cardiovascular diseases.
Research led by Dr David Wald at the Wolfson Institute of Preventive Medicine at Barts and The London School of Medicine and Dentistry showed that there was a difference in the reduction in heart disease events between the five trials with the lowest aspirin use (60 per cent of the participants took aspirin) and the five trials with the highest use (91 per cent took aspirin). The observed risk reduction was six per cent but it would have been 15 per cent if no one had been taking aspirin. Research was based on 75 epidemiological studies involving about 50,000 participants and clinical trials involving about 40,000 participants.
"The explanation has important implications," said Dr David Wald, the lead author of the paper. "The negative clinical trial evidence should not close the door on folic acid -- folic acid may still be of benefit in people who have not had a heart attack because they will generally not be taking aspirin."
Tuesday, February 8, 2011
Loneliness is bad for your health
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Loneliness is no fun — and now it appears it's bad for you as well. UCLA researchers report that chronically lonely people may be at higher risk for certain types of inflammatory disease because their feelings of social isolation trigger the activity of pro-inflammatory immune cells.
In their analysis of 93 older adults, the researchers screened for gene function among different types of immune cells and found that genes originating from two particular cell types — plasmacytoid dendritic cells and monocytes — were overexpressed in chronically lonely individuals, compared with the remainder of the sample. These cell types produce an inflammatory response to tissue damage, and are part of the immune system's first line of defense, which produces an immediate inflammatory response to tissue damage.
It's this same inflammatory response that, over the long-term, can promote cardiovascular disease, cancer and neurodegeneration.
Loneliness is no fun — and now it appears it's bad for you as well. UCLA researchers report that chronically lonely people may be at higher risk for certain types of inflammatory disease because their feelings of social isolation trigger the activity of pro-inflammatory immune cells.
In their analysis of 93 older adults, the researchers screened for gene function among different types of immune cells and found that genes originating from two particular cell types — plasmacytoid dendritic cells and monocytes — were overexpressed in chronically lonely individuals, compared with the remainder of the sample. These cell types produce an inflammatory response to tissue damage, and are part of the immune system's first line of defense, which produces an immediate inflammatory response to tissue damage.
It's this same inflammatory response that, over the long-term, can promote cardiovascular disease, cancer and neurodegeneration.
Dark chocolate and cocoa have a greater antioxidant capacity and a greater total flavanol, and polyphenol, content than the fruit juices
It is widely known that fruit contains antioxidants which may be beneficial to health. New research published in the open access journal Chemistry Central Journal demonstrates that chocolate is a rich source of antioxidants and contains more polyphenols and flavanols than fruit juice.
When researchers at the Hershey Center for Health & Nutrition™ compared the antioxidant activity in cocoa powder and fruit powders they found that, gram per gram, there was more antioxidant capacity, and a greater total flavanol content, in the cocoa powder.
Similarly when they compared the amount of antioxidants, per serving, of dark chocolate, cocoa, hot chocolate mix and fruit juices they found that both dark chocolate and cocoa had a greater antioxidant capacity and a greater total flavanol, and polyphenol, content than the fruit juices. However hot chocolate, due to processing (alkalization) of the chocolate, contained little of any.
When researchers at the Hershey Center for Health & Nutrition™ compared the antioxidant activity in cocoa powder and fruit powders they found that, gram per gram, there was more antioxidant capacity, and a greater total flavanol content, in the cocoa powder.
Similarly when they compared the amount of antioxidants, per serving, of dark chocolate, cocoa, hot chocolate mix and fruit juices they found that both dark chocolate and cocoa had a greater antioxidant capacity and a greater total flavanol, and polyphenol, content than the fruit juices. However hot chocolate, due to processing (alkalization) of the chocolate, contained little of any.
Sun exposure, vitamin D may lower risk of multiple sclerosis
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People who spend more time in the sun and those with higher vitamin D levels may be less likely to develop multiple sclerosis (MS), according to a study published in the February 8, 2011, print issue of Neurology®, the medical journal of the American Academy of Neurology. MS is a chronic disease of the brain and spinal cord, usually with recurrent flare-ups of symptoms. It is often preceded by a first episode (or event) of similar symptoms lasting days to weeks.
"Previous studies have found similar results, but this is the first study to look at people who have just had the first symptoms of MS and haven't even been diagnosed with the disease yet," said study author Robyn Lucas, PhD, of Australian National University in Canberra. "Other studies have looked at people who already have MS—then it's hard to know whether having the disease led them to change their habits in the sun or in their diet."
The multi-site study involved 216 people age 18 to 59 who had a first event with symptoms of the type seen in MS. Those people were matched with 395 people with no symptoms of possible MS who were of similar ages, of the same sex and from the same regions of Australia.
The participants reported how much sun they were exposed to during different periods of their lives, and researchers also measured the amount of skin damage participants had from sun exposure and the amount of melanin in their skin. Vitamin D levels (from sun exposure, diet and supplement use) were measured by blood tests.
The risk of having a first event, diagnosed by a doctor, ranged from approximately two to nine new cases for every 100,000 people per year in this study. The reported UV light exposure of participants ranged from about 500 to over 6,000 kilojoules per meter squared. The researchers found that the risk of having a diagnosed first event decreased by 30 percent for each UV increase of 1,000 kilojoules. They also found that people with most evidence of skin damage from sun exposure were 60 percent less likely to develop a first event than the people with the least damage. People with the highest levels of vitamin D also were less likely to have a diagnosed first event than people with the lowest levels.
Studies have shown that MS is more common in latitudes further away from the equator, and this has been confirmed in Australia.
"Added together, the differences in sun exposure, vitamin D levels and skin type accounted for a 32-percent increase in a diagnosed first event from the low to the high latitude regions of Australia," Lucas said.
Lucas noted that the effects of sun exposure and vitamin D acted independently of each other on the risk of first event. "Further research should evaluate both sun exposure and vitamin D for the prevention of MS," Lucas said.
Lucas also stated that people should continue to limit their sun exposure due to skin cancer risks. She also noted that the risks of tanning beds far outweigh any possible protective effect against MS. Exposure to the sun has not been shown to benefit people who already have MS.
People who spend more time in the sun and those with higher vitamin D levels may be less likely to develop multiple sclerosis (MS), according to a study published in the February 8, 2011, print issue of Neurology®, the medical journal of the American Academy of Neurology. MS is a chronic disease of the brain and spinal cord, usually with recurrent flare-ups of symptoms. It is often preceded by a first episode (or event) of similar symptoms lasting days to weeks.
"Previous studies have found similar results, but this is the first study to look at people who have just had the first symptoms of MS and haven't even been diagnosed with the disease yet," said study author Robyn Lucas, PhD, of Australian National University in Canberra. "Other studies have looked at people who already have MS—then it's hard to know whether having the disease led them to change their habits in the sun or in their diet."
The multi-site study involved 216 people age 18 to 59 who had a first event with symptoms of the type seen in MS. Those people were matched with 395 people with no symptoms of possible MS who were of similar ages, of the same sex and from the same regions of Australia.
The participants reported how much sun they were exposed to during different periods of their lives, and researchers also measured the amount of skin damage participants had from sun exposure and the amount of melanin in their skin. Vitamin D levels (from sun exposure, diet and supplement use) were measured by blood tests.
The risk of having a first event, diagnosed by a doctor, ranged from approximately two to nine new cases for every 100,000 people per year in this study. The reported UV light exposure of participants ranged from about 500 to over 6,000 kilojoules per meter squared. The researchers found that the risk of having a diagnosed first event decreased by 30 percent for each UV increase of 1,000 kilojoules. They also found that people with most evidence of skin damage from sun exposure were 60 percent less likely to develop a first event than the people with the least damage. People with the highest levels of vitamin D also were less likely to have a diagnosed first event than people with the lowest levels.
Studies have shown that MS is more common in latitudes further away from the equator, and this has been confirmed in Australia.
"Added together, the differences in sun exposure, vitamin D levels and skin type accounted for a 32-percent increase in a diagnosed first event from the low to the high latitude regions of Australia," Lucas said.
Lucas noted that the effects of sun exposure and vitamin D acted independently of each other on the risk of first event. "Further research should evaluate both sun exposure and vitamin D for the prevention of MS," Lucas said.
Lucas also stated that people should continue to limit their sun exposure due to skin cancer risks. She also noted that the risks of tanning beds far outweigh any possible protective effect against MS. Exposure to the sun has not been shown to benefit people who already have MS.
New explanation for heart-healthy benefits of chocolate
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In time for the chocolate-giving and chocolate-noshing fest on Valentine's Day, scientists are reporting discovery of how this treat boosts the body's production of high-density lipoprotein cholesterol (HDL) — the "good" form of cholesterol that protects against heart disease. Just as those boxes of chocolates get hearts throbbing and mouths watering, polyphenols in chocolate rev up the activity of certain proteins, including proteins that attach to the genetic material DNA in ways that boost HDL levels. Their report appears in the Journal of Agricultural and Food Chemistry, one of 39 peer-reviewed scientific journals published by the American Chemical Society.
Midori Natsume, Ph.D., and colleagues note that studies have shown that cocoa, the main ingredient in chocolate, appears to reduce the risk of heart disease by boosting levels of HDL, or "good" cholesterol, and decreasing levels of low-density lipoprotein (LDL), or "bad" cholesterol. Credit for those heart-healthy effects goes to a cadre of antioxidant compounds in cocoa called polyphenols, which are particularly abundant in dark chocolate. Until now, however, nobody knew exactly how the polyphenols in cocoa orchestrated those beneficial effects.
The scientists analyzed the effects of cocoa polyphenols on cholesterol using cultures of human liver and intestinal cells. They focused on the production of apolipoprotein A1 (ApoA1), a protein that is the major component of "good" cholesterol, and apolipoprotein B (ApoB), the main component of "bad" cholesterol. It turns out that cocoa polyphenols increased ApoA1 levels and decreased ApoB levels in both the liver and intestine. Further, the scientists discovered that the polyphenols seem to work by enhancing the activity of so-called sterol regulatory element binding proteins (SREBPs). SREBPs attach to the genetic material DNA and activate genes that boost ApoA1 levels, increasing "good" cholesterol. The scientists also found that polyphenols appear to increase the activity of LDL receptors, proteins that help lower "bad" cholesterol levels.
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Here is a Valentine's Day sampler of other recent research on the health benefits chocolate published in ACS journals:
New evidence that dark chocolate helps ease emotional stress
Natural ACE inhibitors in chocolate, wine and tea may help lower blood pressure
In time for the chocolate-giving and chocolate-noshing fest on Valentine's Day, scientists are reporting discovery of how this treat boosts the body's production of high-density lipoprotein cholesterol (HDL) — the "good" form of cholesterol that protects against heart disease. Just as those boxes of chocolates get hearts throbbing and mouths watering, polyphenols in chocolate rev up the activity of certain proteins, including proteins that attach to the genetic material DNA in ways that boost HDL levels. Their report appears in the Journal of Agricultural and Food Chemistry, one of 39 peer-reviewed scientific journals published by the American Chemical Society.
Midori Natsume, Ph.D., and colleagues note that studies have shown that cocoa, the main ingredient in chocolate, appears to reduce the risk of heart disease by boosting levels of HDL, or "good" cholesterol, and decreasing levels of low-density lipoprotein (LDL), or "bad" cholesterol. Credit for those heart-healthy effects goes to a cadre of antioxidant compounds in cocoa called polyphenols, which are particularly abundant in dark chocolate. Until now, however, nobody knew exactly how the polyphenols in cocoa orchestrated those beneficial effects.
The scientists analyzed the effects of cocoa polyphenols on cholesterol using cultures of human liver and intestinal cells. They focused on the production of apolipoprotein A1 (ApoA1), a protein that is the major component of "good" cholesterol, and apolipoprotein B (ApoB), the main component of "bad" cholesterol. It turns out that cocoa polyphenols increased ApoA1 levels and decreased ApoB levels in both the liver and intestine. Further, the scientists discovered that the polyphenols seem to work by enhancing the activity of so-called sterol regulatory element binding proteins (SREBPs). SREBPs attach to the genetic material DNA and activate genes that boost ApoA1 levels, increasing "good" cholesterol. The scientists also found that polyphenols appear to increase the activity of LDL receptors, proteins that help lower "bad" cholesterol levels.
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Here is a Valentine's Day sampler of other recent research on the health benefits chocolate published in ACS journals:
New evidence that dark chocolate helps ease emotional stress
Natural ACE inhibitors in chocolate, wine and tea may help lower blood pressure
Late nights can lead to higher risk of strokes and heart attacks
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New research from Warwick Medical School published today in the European Heart Journal shows that prolonged sleep deprivation and disrupted sleep patterns can have long-term, serious health implications. Leading academics from the University have linked lack of sleep to strokes, heart attacks and cardiovascular disorders which often result in early death.
Professor Francesco Cappuccio from the University of Warwick Medical School, explained: "If you sleep less than six hours per night and have disturbed sleep you stand a 48 per cent greater chance of developing or dying from heart disease and a 15 per cent greater chance of developing or dying of a stroke.
"The trend for late nights and early mornings is actually a ticking time bomb for our health so you need to act now to reduce your risk of developing these life-threatening conditions."
Professor Cappuccio and co-author Dr Michelle Miller, from the University of Warwick, conducted the research programme which followed up evidence from seven to 25 years from more than 470,000 participants from eight countries including Japan, USA, Sweden and UK.
Professor Cappuccio explained: "There is an expectation in today's society to fit more into our lives. The whole work/life balance struggle is causing too many of us to trade in precious sleeping time to ensure we complete all the jobs we believe are expected of us."
He added: "But in doing so, we are significantly increasing the risk of suffering a stroke or developing cardiovascular disease resulting in, for example, heart attacks."
Dr Miller explained further: "Chronic short sleep produces hormones and chemicals in the body which increase the risk of developing heart disease and strokes, and other conditions like high blood pressure and cholesterol, diabetes and obesity".
But Professor Cappuccio did warn of the implications of going too far the other way, as sleeping overly long – more than nine hours at a stretch – may be an indicator of illness, including cardiovascular disease.
"By ensuring you have about seven hours sleep a night, you are protecting your future health, and reducing the risk of developing chronic illnesses. The link is clear from our research: get the sleep you need to stay healthy and live longer."
New research from Warwick Medical School published today in the European Heart Journal shows that prolonged sleep deprivation and disrupted sleep patterns can have long-term, serious health implications. Leading academics from the University have linked lack of sleep to strokes, heart attacks and cardiovascular disorders which often result in early death.
Professor Francesco Cappuccio from the University of Warwick Medical School, explained: "If you sleep less than six hours per night and have disturbed sleep you stand a 48 per cent greater chance of developing or dying from heart disease and a 15 per cent greater chance of developing or dying of a stroke.
"The trend for late nights and early mornings is actually a ticking time bomb for our health so you need to act now to reduce your risk of developing these life-threatening conditions."
Professor Cappuccio and co-author Dr Michelle Miller, from the University of Warwick, conducted the research programme which followed up evidence from seven to 25 years from more than 470,000 participants from eight countries including Japan, USA, Sweden and UK.
Professor Cappuccio explained: "There is an expectation in today's society to fit more into our lives. The whole work/life balance struggle is causing too many of us to trade in precious sleeping time to ensure we complete all the jobs we believe are expected of us."
He added: "But in doing so, we are significantly increasing the risk of suffering a stroke or developing cardiovascular disease resulting in, for example, heart attacks."
Dr Miller explained further: "Chronic short sleep produces hormones and chemicals in the body which increase the risk of developing heart disease and strokes, and other conditions like high blood pressure and cholesterol, diabetes and obesity".
But Professor Cappuccio did warn of the implications of going too far the other way, as sleeping overly long – more than nine hours at a stretch – may be an indicator of illness, including cardiovascular disease.
"By ensuring you have about seven hours sleep a night, you are protecting your future health, and reducing the risk of developing chronic illnesses. The link is clear from our research: get the sleep you need to stay healthy and live longer."
Lack of sleep found to be a new risk factor for colon cancer
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An inadequate amount of sleep has been associated with higher risks of obesity, heart disease, diabetes, and death. Now colon cancer can be added to the list.
In a ground-breaking new study published in the Feb. 15, 2011 issue of the journal Cancer, researchers from University Hospitals (UH) Case Medical Center and Case Western Reserve University School of Medicine, found that individuals who averaged less than six hours of sleep at night had an almost 50 percent increase in the risk of colorectal adenomas compared with individuals sleeping at least seven hours per night. Adenomas are a precursor to cancer tumors, and left untreated, they can turn malignant.
"To our knowledge, this is the first study to report a significant association of sleep duration and colorectal adenomas," said Li Li, MD, PhD, the study's principal investigator, family medicine physician in the Department of Family Medicine at UH Case Medical Center and Associate Professor of Family Medicine, Epidemiology and Biostatistics at Case Western Reserve University School of Medicine. "A short amount of sleep can now be viewed as a new risk factor for the development of the development of colon cancer."
In the study, patients were surveyed by phone prior to coming into the hospital for scheduled colonoscopies at UH Case Medical Center. They were asked demographic information as well as questions from the Pittsburg Sleep Quality Index (PSQI), which obtains information about the patient's overall sleep quality during the past month. The PSQI asks for such information as how frequently one has trouble sleeping and how much sleep one has had per night. The study was funded by the National Cancer Institute through Case Western Reserve University School of Medicine.
Of the 1,240 patients, 338 were diagnosed with colorectal adenomas at their colonoscopy. The patients with adenomas were found in general to have reported sleeping less than six hours compared to compared to those patients without adenomas (control) patients, and the association between amount of sleep and adenomas remained even when adjusted for family history, smoking, and waist-to-hip ratio (a measurement of obesity).
The researchers also found a slightly stronger association of sleep duration with adenomas with women compared to men, but the difference was not statistically significant.
Dr Li said the magnitude of the increase in risk due to less hours of sleep is comparable to the risk associated with having a first-degree relative (parent or sibling) with colon cancer, as well as with high, red meat intake. "Short sleep duration is a public health hazard leading not only to obesity, diabetes and coronary heart disease, but also, as we now have shown in this study, colon adenomas," he said. "Effective intervention to increase duration of sleep and improve quality of sleep could be an under-appreciated avenue for prevention of colorectal cancer."
Although why fewer hours of sleep may lead to colon cancer is unknown, Dr. Li said some of theories include that less sleep may mean less production of melatonin, a natural hormone that in animals has been linked to DNA repair, or that insulin resistance may underlie the link between sleep disturbance and cancer development.
An inadequate amount of sleep has been associated with higher risks of obesity, heart disease, diabetes, and death. Now colon cancer can be added to the list.
In a ground-breaking new study published in the Feb. 15, 2011 issue of the journal Cancer, researchers from University Hospitals (UH) Case Medical Center and Case Western Reserve University School of Medicine, found that individuals who averaged less than six hours of sleep at night had an almost 50 percent increase in the risk of colorectal adenomas compared with individuals sleeping at least seven hours per night. Adenomas are a precursor to cancer tumors, and left untreated, they can turn malignant.
"To our knowledge, this is the first study to report a significant association of sleep duration and colorectal adenomas," said Li Li, MD, PhD, the study's principal investigator, family medicine physician in the Department of Family Medicine at UH Case Medical Center and Associate Professor of Family Medicine, Epidemiology and Biostatistics at Case Western Reserve University School of Medicine. "A short amount of sleep can now be viewed as a new risk factor for the development of the development of colon cancer."
In the study, patients were surveyed by phone prior to coming into the hospital for scheduled colonoscopies at UH Case Medical Center. They were asked demographic information as well as questions from the Pittsburg Sleep Quality Index (PSQI), which obtains information about the patient's overall sleep quality during the past month. The PSQI asks for such information as how frequently one has trouble sleeping and how much sleep one has had per night. The study was funded by the National Cancer Institute through Case Western Reserve University School of Medicine.
Of the 1,240 patients, 338 were diagnosed with colorectal adenomas at their colonoscopy. The patients with adenomas were found in general to have reported sleeping less than six hours compared to compared to those patients without adenomas (control) patients, and the association between amount of sleep and adenomas remained even when adjusted for family history, smoking, and waist-to-hip ratio (a measurement of obesity).
The researchers also found a slightly stronger association of sleep duration with adenomas with women compared to men, but the difference was not statistically significant.
Dr Li said the magnitude of the increase in risk due to less hours of sleep is comparable to the risk associated with having a first-degree relative (parent or sibling) with colon cancer, as well as with high, red meat intake. "Short sleep duration is a public health hazard leading not only to obesity, diabetes and coronary heart disease, but also, as we now have shown in this study, colon adenomas," he said. "Effective intervention to increase duration of sleep and improve quality of sleep could be an under-appreciated avenue for prevention of colorectal cancer."
Although why fewer hours of sleep may lead to colon cancer is unknown, Dr. Li said some of theories include that less sleep may mean less production of melatonin, a natural hormone that in animals has been linked to DNA repair, or that insulin resistance may underlie the link between sleep disturbance and cancer development.
Friday, February 4, 2011
Review confirms benefits of outdoor exercise
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A systematic review carried out by a team at the Peninsula College of Medicine and Dentistry has analysed existing studies and concluded that there are benefits to mental and physical well-being from taking exercise in the natural environment. Their findings are published in the leading research journal Environmental Science and Technology today, 4th February 2011.
The research team, supported by the NIHR Peninsula Collaboration in Leadership for Applied Health Research and Care (PenCLAHRC, part of the NIHR family of health and research initiatives) in collaboration with the European Centre for the Environment and Human Health (ECEHH), analysed data from a number of sources including 11 randomised and non-randomised control trials incorporating information from 833 adults.
Eligible trials were those that compared the effects of outdoor exercise initiatives with those conducted indoors and which reported at least one physical or mental well-being outcome in adults or children.
The study found that most trials showed an improvement in mental well-being: compared with exercising indoors, exercising in natural environments was associated with greater feelings of revitalisation, increased energy and positive engagement, together with decreases in tension, confusion, anger and depression. Participants also reported greater enjoyment and satisfaction with outdoor activity and stated that they were more likely to repeat the activity at a later date.
However, none of the identified studies measured the effects of physical activity on physical well-being, or the effect of natural environments on sticking to exercise.
On balance this review has identified some promising effects on self-reported mental well-being immediately following exercise in the natural environment, as opposed to those reported following exercise indoors. This is a first step towards vindicating the positive effects of programmes such as the Green Gym and Blue Gym, and innovative interventions by medical practitioners that include exercise outdoors as part of holistic treatments for those suffering from depression and similar psychological ailments.
At present research analysts are working with a paucity of high quality evidence, and one significant outcome from this study is the urgent need for there to be further research in this area. Large, well-designed longer-term trials in populations who might benefit most from the potential advantages of outdoor exercise are needed to fully analyse the effects of outdoor exercise on mental and physical well-being. Studies are also required that measure the influence of such effects on the sustainability of physical activity.
A systematic review carried out by a team at the Peninsula College of Medicine and Dentistry has analysed existing studies and concluded that there are benefits to mental and physical well-being from taking exercise in the natural environment. Their findings are published in the leading research journal Environmental Science and Technology today, 4th February 2011.
The research team, supported by the NIHR Peninsula Collaboration in Leadership for Applied Health Research and Care (PenCLAHRC, part of the NIHR family of health and research initiatives) in collaboration with the European Centre for the Environment and Human Health (ECEHH), analysed data from a number of sources including 11 randomised and non-randomised control trials incorporating information from 833 adults.
Eligible trials were those that compared the effects of outdoor exercise initiatives with those conducted indoors and which reported at least one physical or mental well-being outcome in adults or children.
The study found that most trials showed an improvement in mental well-being: compared with exercising indoors, exercising in natural environments was associated with greater feelings of revitalisation, increased energy and positive engagement, together with decreases in tension, confusion, anger and depression. Participants also reported greater enjoyment and satisfaction with outdoor activity and stated that they were more likely to repeat the activity at a later date.
However, none of the identified studies measured the effects of physical activity on physical well-being, or the effect of natural environments on sticking to exercise.
On balance this review has identified some promising effects on self-reported mental well-being immediately following exercise in the natural environment, as opposed to those reported following exercise indoors. This is a first step towards vindicating the positive effects of programmes such as the Green Gym and Blue Gym, and innovative interventions by medical practitioners that include exercise outdoors as part of holistic treatments for those suffering from depression and similar psychological ailments.
At present research analysts are working with a paucity of high quality evidence, and one significant outcome from this study is the urgent need for there to be further research in this area. Large, well-designed longer-term trials in populations who might benefit most from the potential advantages of outdoor exercise are needed to fully analyse the effects of outdoor exercise on mental and physical well-being. Studies are also required that measure the influence of such effects on the sustainability of physical activity.
Wednesday, February 2, 2011
Vegans' elevated heart risk requires omega-3s and B12
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People who follow a vegan lifestyle — strict vegetarians who try to eat no meat or animal products of any kind — may increase their risk of developing blood clots and atherosclerosis or "hardening of the arteries," which are conditions that can lead to heart attacks and stroke. That's the conclusion of a review of dozens of articles published on the biochemistry of vegetarianism during the past 30 years. The article,
"Chemistry behind Vegetarianism," appears in ACS' bi-weekly Journal of Agricultural and Food Chemistry.
Duo Li notes in the review that meat eaters are known for having a significantly higher combination of cardiovascular risk factors than vegetarians. Lower-risk vegans, however, may not be immune. Their diets tend to be lacking several key nutrients — including iron, zinc, vitamin B12, and omega-3 fatty acids. While a balanced vegetarian diet can provide enough protein, this isn't always the case when it comes to fat and fatty acids. As a result, vegans tend to have elevated blood levels of homocysteine and decreased levels of HDL, the "good" form of cholesterol. Both are risk factors for heart disease.
It concludes that there is a strong scientific basis for vegetarians and vegans to increase their dietary omega-3 fatty acids and vitamin B12 to help contend with those risks. Good sources of omega-3s include salmon and other oily fish, walnuts and certain other nuts. Good sources of vitamin B12 include seafood, eggs, and fortified milk. Dietary supplements also can supply these nutrients.
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People who follow a vegan lifestyle — strict vegetarians who try to eat no meat or animal products of any kind — may increase their risk of developing blood clots and atherosclerosis or "hardening of the arteries," which are conditions that can lead to heart attacks and stroke. That's the conclusion of a review of dozens of articles published on the biochemistry of vegetarianism during the past 30 years. The article,
"Chemistry behind Vegetarianism," appears in ACS' bi-weekly Journal of Agricultural and Food Chemistry.
Duo Li notes in the review that meat eaters are known for having a significantly higher combination of cardiovascular risk factors than vegetarians. Lower-risk vegans, however, may not be immune. Their diets tend to be lacking several key nutrients — including iron, zinc, vitamin B12, and omega-3 fatty acids. While a balanced vegetarian diet can provide enough protein, this isn't always the case when it comes to fat and fatty acids. As a result, vegans tend to have elevated blood levels of homocysteine and decreased levels of HDL, the "good" form of cholesterol. Both are risk factors for heart disease.
It concludes that there is a strong scientific basis for vegetarians and vegans to increase their dietary omega-3 fatty acids and vitamin B12 to help contend with those risks. Good sources of omega-3s include salmon and other oily fish, walnuts and certain other nuts. Good sources of vitamin B12 include seafood, eggs, and fortified milk. Dietary supplements also can supply these nutrients.
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An extra 5 years of life an unexpected benefit of osteoporosis treatment
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Australian clinical researchers have noted an extraordinary and unexpected benefit of osteoporosis treatment – that people taking bisphosphonates are not only surviving well, better than people without osteoporosis, they appear to be gaining an extra five years of life. These findings are published in the Journal of Clinical Endocrinology and Metabolism, now online.
Associate Professor Jacqueline Center and Professor John Eisman, from Sydney's Garvan Institute of Medical Research, based their findings on data from the long running Dubbo Osteoporosis Epidemiology Study.
Out of a total cohort of around 2,000, a sub-group of 121 people were treated with bisphosphonates for an average of 3 years. When compared with other sub-groups taking other forms of treatment, such as Vitamin D (with or without calcium) or hormone therapy, the longer life associated with bisphosphonate treatment was marked and clear.
"While the results seemed surprisingly good, they are borne out by the data – within the limitations of any study – and appear to apply to men as well as women," said Associate Professor Center. "When we first looked at the figures, we thought that there had to be a fallacy, that we were missing something. One of the most obvious things might be that these are people who seek medical attention, so may be healthier and live longer. So we compared the bisphosphonate group with people taking Vitamin D and calcium or women on hormone therapy."
"The comparison against these other groups of similarly health-aware people simply confirmed that our results were not skewed by that factor." Center continued. "In a group of women with osteoporotic fractures over the age of 75, you would expect 50 percent to die over a period of five years. Among women in that age group who took bisphosphonates, the death rate dropped to 10 percent. Similarly, in a group of younger women, where you would expect 20-25 percent to die over five years, there were no deaths. The data were consistent with about a five year survival advantage for people on bisphosphonates."
"We speculate that it may have something to do with the fact that bone acts as a repository for toxic heavy metals such as lead and cadmium," said Professor Eisman. "So when people get older, they lose bone. When this happens, these toxic materials are released back into the body and may adversely affect health. By preventing bone loss, bisphosphonates prevent some of this toxic metal release. While we know that this is the case, we don't yet have evidence that this produces the survival benefit."
Australian clinical researchers have noted an extraordinary and unexpected benefit of osteoporosis treatment – that people taking bisphosphonates are not only surviving well, better than people without osteoporosis, they appear to be gaining an extra five years of life. These findings are published in the Journal of Clinical Endocrinology and Metabolism, now online.
Associate Professor Jacqueline Center and Professor John Eisman, from Sydney's Garvan Institute of Medical Research, based their findings on data from the long running Dubbo Osteoporosis Epidemiology Study.
Out of a total cohort of around 2,000, a sub-group of 121 people were treated with bisphosphonates for an average of 3 years. When compared with other sub-groups taking other forms of treatment, such as Vitamin D (with or without calcium) or hormone therapy, the longer life associated with bisphosphonate treatment was marked and clear.
"While the results seemed surprisingly good, they are borne out by the data – within the limitations of any study – and appear to apply to men as well as women," said Associate Professor Center. "When we first looked at the figures, we thought that there had to be a fallacy, that we were missing something. One of the most obvious things might be that these are people who seek medical attention, so may be healthier and live longer. So we compared the bisphosphonate group with people taking Vitamin D and calcium or women on hormone therapy."
"The comparison against these other groups of similarly health-aware people simply confirmed that our results were not skewed by that factor." Center continued. "In a group of women with osteoporotic fractures over the age of 75, you would expect 50 percent to die over a period of five years. Among women in that age group who took bisphosphonates, the death rate dropped to 10 percent. Similarly, in a group of younger women, where you would expect 20-25 percent to die over five years, there were no deaths. The data were consistent with about a five year survival advantage for people on bisphosphonates."
"We speculate that it may have something to do with the fact that bone acts as a repository for toxic heavy metals such as lead and cadmium," said Professor Eisman. "So when people get older, they lose bone. When this happens, these toxic materials are released back into the body and may adversely affect health. By preventing bone loss, bisphosphonates prevent some of this toxic metal release. While we know that this is the case, we don't yet have evidence that this produces the survival benefit."
Roasting coffee beans a dark brown produces valued antioxidants
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Food scientists at the University of British Columbia have been able to pinpoint more of the complex chemistry behind coffee’s much touted antioxidant benefits, tracing valuable compounds to the roasting process.
Lead author Yazheng Liu and co-author Prof. David Kitts found that the prevailing antioxidants present in dark roasted coffee brew extracts result from the green beans being browned under high temperatures.
Their findings will appear in a forthcoming issue of Food Research International and can be previewed here.
Liu and Kitts analyzed the complex mixture of chemical compounds produced during the bean’s browning process, called the “Maillard reaction.” The term refers to the work by French chemist Louis-Camille Maillard who in the 1900s looked at how heat affects the carbohydrates, sugars and proteins in food, such as when grilling steaks or toasting bread.
Antioxidants aid in removing free radicals, the end products of metabolism which have been linked to the aging process.
“Previous studies suggested that antioxidants in coffee could be traced to caffeine or the chlorogenic acid found in green coffee beans, but our results clearly show that the Maillard reaction is the main source of antioxidants,” says Liu, an MSc student in the Faculty of Land and Food Systems (LFS).
“We found, for example, that coffee beans lose 90 per cent of their chlorogenic acid during the roasting process,” says Kitts, LFS food science professor and director of the Food, Nutrition and Health program.
The UBC study sheds light on an area of research that has yielded largely inconsistent findings. While some scientists report increased antioxidant activity in coffee made from dark roasted beans, others found a decrease. Yet other theories insist that medium roast coffees yield the highest level of antioxidant activity.
Food scientists at the University of British Columbia have been able to pinpoint more of the complex chemistry behind coffee’s much touted antioxidant benefits, tracing valuable compounds to the roasting process.
Lead author Yazheng Liu and co-author Prof. David Kitts found that the prevailing antioxidants present in dark roasted coffee brew extracts result from the green beans being browned under high temperatures.
Their findings will appear in a forthcoming issue of Food Research International and can be previewed here.
Liu and Kitts analyzed the complex mixture of chemical compounds produced during the bean’s browning process, called the “Maillard reaction.” The term refers to the work by French chemist Louis-Camille Maillard who in the 1900s looked at how heat affects the carbohydrates, sugars and proteins in food, such as when grilling steaks or toasting bread.
Antioxidants aid in removing free radicals, the end products of metabolism which have been linked to the aging process.
“Previous studies suggested that antioxidants in coffee could be traced to caffeine or the chlorogenic acid found in green coffee beans, but our results clearly show that the Maillard reaction is the main source of antioxidants,” says Liu, an MSc student in the Faculty of Land and Food Systems (LFS).
“We found, for example, that coffee beans lose 90 per cent of their chlorogenic acid during the roasting process,” says Kitts, LFS food science professor and director of the Food, Nutrition and Health program.
The UBC study sheds light on an area of research that has yielded largely inconsistent findings. While some scientists report increased antioxidant activity in coffee made from dark roasted beans, others found a decrease. Yet other theories insist that medium roast coffees yield the highest level of antioxidant activity.
Tuesday, February 1, 2011
Want more efficient muscles? Eat your spinach
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After taking a small dose of inorganic nitrate for three days, healthy people consume less oxygen while riding an exercise bike. A new study in the February issue of Cell Metabolism traces that improved performance to increased efficiency of the mitochondria that power our cells.
The researchers aren't recommending anyone begin taking inorganic nitrate supplements based on the new findings. Rather, they say that the results may offer one explanation for the well-known health benefits of fruits and vegetables, and leafy green vegetables in particular.
"We're talking about an amount of nitrate equivalent to what is found in two or three red beets or a plate of spinach," said Eddie Weitzberg of the Karolinska Institutet in Sweden. "We know that diets rich in fruits and vegetables can help prevent cardiovascular disease and diabetes but the active nutrients haven't been clear. This shows inorganic nitrate as a candidate to explain those benefits."
In fact, up until recently nitrate wasn't thought to have any nutritional value at all. It has even been suggested that this component of vegetables might be toxic. But Weitzberg and his colleague Jon Lundberg earlier showed that dietary nitrate feeds into a pathway that produces nitric oxide with the help of friendly bacteria found in our mouths. Nitric oxide has been known for two decades as a physiologically important molecule. It opens up our blood vessels to lower blood pressure, for instance.
The new study offers yet another benefit of nitrate and the nitric oxides that stem from them. It appears that the increased mitochondrial efficiency is owed to lower levels of proteins that normally make the cellular powerhouses leaky. "Mitochondria normally aren't fully efficient," Weitzberg explained. "No machine is."
Questions do remain. The new results show that increased dietary nitrate can have a rather immediate effect. But it's not yet clear what might happen in people who consume higher levels of inorganic nitrate over longer periods of time. Weitzberg says it will be a natural next step to repeat the experiment in people with conditions linked to mitochondrial dysfunction, including diabetes and cardiovascular disease, to see if they too enjoy the benefits of nitrates.
"Among the more consistent findings from nutritional research are the beneficial effects of a high intake of fruit and vegetables in protection against major disorders such as cardiovascular disease and diabetes," the researchers concluded. "However, the underlying mechanism(s) responsible for these effects is still unclear, and trials with single nutrients have generally failed. It is tempting to speculate that boosting of the nitrate-nitrite-NO pathway may be one mechanism by which vegetables exert their protective effects."
As an interesting aside, Weitzberg says that the benefits of dietary nitrates suggest that powerful mouthwashes may have a downside. "We need oral bacteria for the first step in nitrate reduction," he says. "You could block the effects of inorganic nitrate if you use a strong mouthwash or spit [instead of swallowing your saliva]. In our view, strong mouthwashes are not good if you want this system to work."
The group has also recently shown that nitrate reduces the blood pressure of healthy individuals and that in laboratory animals it counteracts components of the metabolic syndrome, a pre-stage of diabetes. Other scientists have demonstrated protective effects of nitrate and nitrite in animal models against heart attack and stroke.
Ω
After taking a small dose of inorganic nitrate for three days, healthy people consume less oxygen while riding an exercise bike. A new study in the February issue of Cell Metabolism traces that improved performance to increased efficiency of the mitochondria that power our cells.
The researchers aren't recommending anyone begin taking inorganic nitrate supplements based on the new findings. Rather, they say that the results may offer one explanation for the well-known health benefits of fruits and vegetables, and leafy green vegetables in particular.
"We're talking about an amount of nitrate equivalent to what is found in two or three red beets or a plate of spinach," said Eddie Weitzberg of the Karolinska Institutet in Sweden. "We know that diets rich in fruits and vegetables can help prevent cardiovascular disease and diabetes but the active nutrients haven't been clear. This shows inorganic nitrate as a candidate to explain those benefits."
In fact, up until recently nitrate wasn't thought to have any nutritional value at all. It has even been suggested that this component of vegetables might be toxic. But Weitzberg and his colleague Jon Lundberg earlier showed that dietary nitrate feeds into a pathway that produces nitric oxide with the help of friendly bacteria found in our mouths. Nitric oxide has been known for two decades as a physiologically important molecule. It opens up our blood vessels to lower blood pressure, for instance.
The new study offers yet another benefit of nitrate and the nitric oxides that stem from them. It appears that the increased mitochondrial efficiency is owed to lower levels of proteins that normally make the cellular powerhouses leaky. "Mitochondria normally aren't fully efficient," Weitzberg explained. "No machine is."
Questions do remain. The new results show that increased dietary nitrate can have a rather immediate effect. But it's not yet clear what might happen in people who consume higher levels of inorganic nitrate over longer periods of time. Weitzberg says it will be a natural next step to repeat the experiment in people with conditions linked to mitochondrial dysfunction, including diabetes and cardiovascular disease, to see if they too enjoy the benefits of nitrates.
"Among the more consistent findings from nutritional research are the beneficial effects of a high intake of fruit and vegetables in protection against major disorders such as cardiovascular disease and diabetes," the researchers concluded. "However, the underlying mechanism(s) responsible for these effects is still unclear, and trials with single nutrients have generally failed. It is tempting to speculate that boosting of the nitrate-nitrite-NO pathway may be one mechanism by which vegetables exert their protective effects."
As an interesting aside, Weitzberg says that the benefits of dietary nitrates suggest that powerful mouthwashes may have a downside. "We need oral bacteria for the first step in nitrate reduction," he says. "You could block the effects of inorganic nitrate if you use a strong mouthwash or spit [instead of swallowing your saliva]. In our view, strong mouthwashes are not good if you want this system to work."
The group has also recently shown that nitrate reduces the blood pressure of healthy individuals and that in laboratory animals it counteracts components of the metabolic syndrome, a pre-stage of diabetes. Other scientists have demonstrated protective effects of nitrate and nitrite in animal models against heart attack and stroke.
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