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Physical activity requires strong, healthy muscles. Fortunately, when people exercise on a regular basis, their muscles experience a continuous cycle of muscle breakdown (during exercise) and compensatory remodeling and growth (especially with weightlifting). Athletes have long experimented with methods to augment these physiologic responses to enhance muscle growth. One such ergogenic aid that has gained recent popularity is the use of high-quality, high-protein beverages during and after exercise, with dairy-based drinks enriched with whey proteins often taking front stage. Many studies have documented a beneficial effect of their consumption. Of particular interest is the effect of the essential amino acid leucine contained in these products. Two papers, published in the September 2011 issue of The American Journal of Clinical Nutrition, report the results of 2 independent studies conducted to understand better how amino acids influence protein synthesis in recreational athletes.
According to ASN Spokesperson Shelley McGuire, PhD: "These studies, and others like them, help us understand and apply something we all inherently know: the human body works in a complex, yet completely logical way! It makes good sense that consuming a food containing high-quality protein (like milk) during and/or immediately following exercise would help muscles get stronger. Muscle strength doesn't just happen on its own - our muscles need to be both encouraged (as happens via exercise) and nourished (as happens when we eat well). Now we have even more scientific proof for this common-sense concept."
In the first study, researchers led by Stuart Phillips (McMaster University) investigated whether postexercise muscle protein synthesis is different when a large, single dose of whey protein (25 g) is consumed immediately after activity compared with when smaller doses (2.5 g) are consumed 10 times over an extended period. The idea with the small "protein shots" was to mimic how another milk protein, casein, is digested. Participants (8 men; mean age: 22 y) performed 8 sets of 8 repetitions on a leg-extension machine; each subject participated in both dietary treatment regimens. In the second study led by Stefan Pasiakos from the US Army Research Institute of Environmental Medicine, active-duty military personnel (7 men and 1 woman; mean age: 24 y) consumed a high-protein beverage (10 g protein as essential amino acids) containing 1.87 or 3.5 g leucine while exercising on a stationary bicycle. In both studies, postexercise muscle protein synthesis was evaluated.
Consuming the large bolus of whey protein immediately after exercise increased muscle protein synthesis more than when periodic smaller doses of protein were consumed. In the second study, muscle protein synthesis was 33% greater after consumption of the leucine-enriched protein beverage than after the lower-leucine drink.
The researchers concluded that muscle metabolism after exercise can be manipulated via dietary means. In terms of the most beneficial timing of protein intake, immediate postexercise consumption appears to be best. Furthermore, leucine may play an especially important role in stimulating muscle growth in the postactivity recovery period.
Thursday, August 18, 2011
Four Specific Health Behaviors Contribute to a Longer Life
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A new CDC report finds that people can live longer if they practice one or more healthy lifestyle behaviors— not smoking, eating a healthy diet, getting regular physical activity, and limiting alcohol consumption. Not smoking provides the most protection from dying early from all causes.
The study, “Low Risk Lifestyle Behaviors and All-Cause Mortality: Findings from the National Health and Nutrition Examination Survey III Mortality Study,” is published online today by the American Journal of Public Health.
People who engaged in all four healthy behaviors were 66 percent less likely to die early from cancer, 65 percent less likely to die early from cardiovascular disease, and 57 percent less likely to die early from other causes compared to people who did not engage in any of the healthy behaviors.
What You Can Do to Live a Healthier and Longer Life:
Avoid Excessive Alcohol Use
Drink alcohol in moderation (men should have no more than two drinks per day; and women no more than one drink per day).
Avoid Tobacco
Improve Nutrition
- Eat more fruits, vegetables, whole grains, fat-free and low-fat dairy products, and seafood.
- Eat fewer foods with sodium (salt), saturated fats, trans fats, cholesterol, added sugars, and refined grains.
Engage in Physical Activity
- Participate in moderate intensity physical activity 5 or more days per week (150 minutes), such as brisk walking, or
- Practice vigorous physical activity 3 or more days per week (75 minutes) such as jogging or race walking.
A new CDC report finds that people can live longer if they practice one or more healthy lifestyle behaviors— not smoking, eating a healthy diet, getting regular physical activity, and limiting alcohol consumption. Not smoking provides the most protection from dying early from all causes.
The study, “Low Risk Lifestyle Behaviors and All-Cause Mortality: Findings from the National Health and Nutrition Examination Survey III Mortality Study,” is published online today by the American Journal of Public Health.
People who engaged in all four healthy behaviors were 66 percent less likely to die early from cancer, 65 percent less likely to die early from cardiovascular disease, and 57 percent less likely to die early from other causes compared to people who did not engage in any of the healthy behaviors.
What You Can Do to Live a Healthier and Longer Life:
Avoid Excessive Alcohol Use
Drink alcohol in moderation (men should have no more than two drinks per day; and women no more than one drink per day).
Avoid Tobacco
Improve Nutrition
- Eat more fruits, vegetables, whole grains, fat-free and low-fat dairy products, and seafood.
- Eat fewer foods with sodium (salt), saturated fats, trans fats, cholesterol, added sugars, and refined grains.
Engage in Physical Activity
- Participate in moderate intensity physical activity 5 or more days per week (150 minutes), such as brisk walking, or
- Practice vigorous physical activity 3 or more days per week (75 minutes) such as jogging or race walking.
Wednesday, August 17, 2011
Popular Herbal Supplements May Adversely Affect Chemotherapy Treatment
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Doctors urge cancer patients to discuss supplements with their doctors before beginning treatment
Acai berry, cumin, herbal tea, turmeric and long-term use of garlic – all herbal supplements commonly believed to be beneficial to your health – may negatively impact chemotherapy treatment according to a new report presented at the recent American Society of Clinical Oncology (ASCO) meeting in Chicago. Researchers from Northwestern Memorial hospital say there is growing evidence that these popular supplements may intensify or weaken the effect of chemotherapy drugs and in some cases, may cause a toxic, even lethal reaction.
“With the growth of the Internet, patients have better access to information about alternative products and often turn to dietary and herbal supplements to treat their illness because they think they’re natural and safe,” said June M. McKoy, MD, geriatrician at Northwestern Memorial Hospital and lead investigator on the ASCO presentation. “What people don’t realize is that supplements are more than just vitamins and can counteract medical therapies if not taken appropriately”.
McKoy, who is also director of geriatric oncology at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University, says more research is needed to understand which supplements interact with chemotherapy drugs and the extent of those interactions and encourages patients to openly communicate with their physicians about the use of supplements.
“Patients need to tell their doctors what medications they are taking – including vitamins and supplements – to avoid any possible interaction,” said McKoy who is also an assistant professor of medicine and preventive medicine at Northwestern University Feinberg School of Medicine.
Herbal supplements, defined as plant or plant parts used for therapeutic purposes, can interact with chemotherapy drugs through different mechanisms. Some herbs can interfere with the metabolism of the drugs, making them less effective while other herbs such as long-term use of garlic may increase the risk of bleeding during surgery. While culinary herbs used in small quantities for flavoring are generally safe, consuming large amounts for prolonged periods of time may have a negative effect on the body when going through chemotherapy. "
Recent research shows that 50 percent of patients undergoing chemotherapy did not tell their doctor they were taking alternative therapies. “Some believe it’s not important, while others are uncomfortable admitting they are pursuing alternative therapies,” said McKoy. “The truth is, integrative approaches can be beneficial for cancer patients, but it’s important to take these approaches at the right time and under the supervision of your doctor.”
McKoy urges patients to stop taking herbal supplements while receiving chemotherapy until more is known about possible interactions, but encourages those who are interested in complementary approaches to have a conversation with their doctor about other approaches that may be beneficial.
“Integrative therapies such as massage, acupuncture and meditation can address important patient needs by alleviating stress, addressing pain and helping patients cope,” said Melinda Ring, MD, medical director for the Northwestern Memorial Physicians Group’s Center for Integrative Medicine and Wellness.
No matter the course of treatment, McKoy stresses the importance of physicians and patients being more cognizant of this potential interaction and encourages communication about all herbal supplement intakes. “Patients should bring in labels and bottles to their appointments. This can help the doctor calibrate drug dosage with other supplements in mind in order to prevent toxicities,” stated McKoy.
McKoy plans to launch a pilot study this summer to examine how frequently conversations about supplements come up between cancer patients and their doctors.
“By identifying communication barriers, we can take steps to improve doctor patient communication in order to prevent potentially dangerous drug interactions,” said McKoy.
Doctors urge cancer patients to discuss supplements with their doctors before beginning treatment
Acai berry, cumin, herbal tea, turmeric and long-term use of garlic – all herbal supplements commonly believed to be beneficial to your health – may negatively impact chemotherapy treatment according to a new report presented at the recent American Society of Clinical Oncology (ASCO) meeting in Chicago. Researchers from Northwestern Memorial hospital say there is growing evidence that these popular supplements may intensify or weaken the effect of chemotherapy drugs and in some cases, may cause a toxic, even lethal reaction.
“With the growth of the Internet, patients have better access to information about alternative products and often turn to dietary and herbal supplements to treat their illness because they think they’re natural and safe,” said June M. McKoy, MD, geriatrician at Northwestern Memorial Hospital and lead investigator on the ASCO presentation. “What people don’t realize is that supplements are more than just vitamins and can counteract medical therapies if not taken appropriately”.
McKoy, who is also director of geriatric oncology at the Robert H. Lurie Comprehensive Cancer Center of Northwestern University, says more research is needed to understand which supplements interact with chemotherapy drugs and the extent of those interactions and encourages patients to openly communicate with their physicians about the use of supplements.
“Patients need to tell their doctors what medications they are taking – including vitamins and supplements – to avoid any possible interaction,” said McKoy who is also an assistant professor of medicine and preventive medicine at Northwestern University Feinberg School of Medicine.
Herbal supplements, defined as plant or plant parts used for therapeutic purposes, can interact with chemotherapy drugs through different mechanisms. Some herbs can interfere with the metabolism of the drugs, making them less effective while other herbs such as long-term use of garlic may increase the risk of bleeding during surgery. While culinary herbs used in small quantities for flavoring are generally safe, consuming large amounts for prolonged periods of time may have a negative effect on the body when going through chemotherapy. "
Recent research shows that 50 percent of patients undergoing chemotherapy did not tell their doctor they were taking alternative therapies. “Some believe it’s not important, while others are uncomfortable admitting they are pursuing alternative therapies,” said McKoy. “The truth is, integrative approaches can be beneficial for cancer patients, but it’s important to take these approaches at the right time and under the supervision of your doctor.”
McKoy urges patients to stop taking herbal supplements while receiving chemotherapy until more is known about possible interactions, but encourages those who are interested in complementary approaches to have a conversation with their doctor about other approaches that may be beneficial.
“Integrative therapies such as massage, acupuncture and meditation can address important patient needs by alleviating stress, addressing pain and helping patients cope,” said Melinda Ring, MD, medical director for the Northwestern Memorial Physicians Group’s Center for Integrative Medicine and Wellness.
No matter the course of treatment, McKoy stresses the importance of physicians and patients being more cognizant of this potential interaction and encourages communication about all herbal supplement intakes. “Patients should bring in labels and bottles to their appointments. This can help the doctor calibrate drug dosage with other supplements in mind in order to prevent toxicities,” stated McKoy.
McKoy plans to launch a pilot study this summer to examine how frequently conversations about supplements come up between cancer patients and their doctors.
“By identifying communication barriers, we can take steps to improve doctor patient communication in order to prevent potentially dangerous drug interactions,” said McKoy.
Fish oil's positive impact on cognition and brain structure
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Researchers at Rhode Island Hospital's Alzheimer's Disease and Memory Disorders Center have found positive associations between fish oil supplements and cognitive functioning as well as differences in brain structure between users and non-users of fish oil supplements. The findings suggest possible benefits of fish oil supplements on brain health and aging. The results were reported at the recent International Conference on Alzheimer's Disease, in Paris, France.
The study was led by Lori Daiello, PharmD, a research scientist at the Rhode Island Hospital Alzheimer's Disease and Memory Disorders Center. Data for the analyses was obtained from the Alzheimer's Disease Neuroimaging Initiative (ADNI), a large multi-center, NIH-funded study that followed older adults with normal cognition, mild cognitive impairment, and Alzheimer's Disease for over three years with periodic memory testing and brain MRIs.
The study included 819 individuals, 117 of whom reported regular use of fish oil supplements before entry and during study follow-up. The researchers compared cognitive functioning and brain atrophy for patients who reported routinely using these supplements to those who were not using fish oil supplements.
Daiello reports that compared to non-users, use of fish oil supplements was associated with better cognitive functioning during the study. However, this association was significant only in those individuals who had a normal baseline cognitive function and in individuals who tested negative for a genetic risk factor for Alzheimer's Disease known as APOE4. This is consistent with previous research.
The unique finding, however, is that there was a clear association between fish oil supplements and brain volume. Consistent with the cognitive outcomes, these observations were significant only for those who were APOE4 negative.
Daiello says, "In the imaging analyses for the entire study population, we found a significant positive association between fish oil supplement use and average brain volumes in two critical areas utilized in memory and thinking (cerebral cortex and hippocampus), as well as smaller brain ventricular volumes compared to non-users at any given time in the study. In other words, fish oil use was associated with less brain shrinkage in patients taking these supplements during the ADNI study compared to those who didn't report using them."
Daiello continues, "These observations should motivate further study of the possible effects of long-term fish oil supplementation on important markers of cognitive decline and the potential influence of genetics on these outco
Researchers at Rhode Island Hospital's Alzheimer's Disease and Memory Disorders Center have found positive associations between fish oil supplements and cognitive functioning as well as differences in brain structure between users and non-users of fish oil supplements. The findings suggest possible benefits of fish oil supplements on brain health and aging. The results were reported at the recent International Conference on Alzheimer's Disease, in Paris, France.
The study was led by Lori Daiello, PharmD, a research scientist at the Rhode Island Hospital Alzheimer's Disease and Memory Disorders Center. Data for the analyses was obtained from the Alzheimer's Disease Neuroimaging Initiative (ADNI), a large multi-center, NIH-funded study that followed older adults with normal cognition, mild cognitive impairment, and Alzheimer's Disease for over three years with periodic memory testing and brain MRIs.
The study included 819 individuals, 117 of whom reported regular use of fish oil supplements before entry and during study follow-up. The researchers compared cognitive functioning and brain atrophy for patients who reported routinely using these supplements to those who were not using fish oil supplements.
Daiello reports that compared to non-users, use of fish oil supplements was associated with better cognitive functioning during the study. However, this association was significant only in those individuals who had a normal baseline cognitive function and in individuals who tested negative for a genetic risk factor for Alzheimer's Disease known as APOE4. This is consistent with previous research.
The unique finding, however, is that there was a clear association between fish oil supplements and brain volume. Consistent with the cognitive outcomes, these observations were significant only for those who were APOE4 negative.
Daiello says, "In the imaging analyses for the entire study population, we found a significant positive association between fish oil supplement use and average brain volumes in two critical areas utilized in memory and thinking (cerebral cortex and hippocampus), as well as smaller brain ventricular volumes compared to non-users at any given time in the study. In other words, fish oil use was associated with less brain shrinkage in patients taking these supplements during the ADNI study compared to those who didn't report using them."
Daiello continues, "These observations should motivate further study of the possible effects of long-term fish oil supplementation on important markers of cognitive decline and the potential influence of genetics on these outco
Milk better than water to rehydrate kids
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Active children need to be watered with milk. It's a more effective way of countering dehydration than a sports drink or water itself, say researchers at McMaster University.
That's particularly important during hot summer weather, says Brian Timmons, research director of the Child Health and Exercise Medicine Program at McMaster and principal investigator of the study.
"Children become dehydrated during exercise, and it's important they get enough fluids, particularly before going into a second round of a game. Milk is better than either a sports drink or water because it is a source of high quality protein, carbohydrates, calcium and electrolytes."
He added that milk replaces sodium lost in sweat and helps the body retain fluid better. As well, the milk provides protein needed by children for muscle development and growth which is not found in the other drinks.
The study of eight to 10-year-olds involved exercising in a climate chamber, then receiving a drink and being measured for hydration.
Timmons, an assistant professor of pediatrics of the Michael G. DeGroote School of Medicine, said active children and adults usually don't drink enough to stay hydrated during exercise, so they often have a "hydration disadvantage" when they start their next period of exercise.
He said that one per cent dehydration can have up to a 15 per cent decrease in performance, with an increased heart rate, core temperature and less ability to keep going. More significant dehydration comes with an increased risk of heat-related illness such as heat stroke.
Active children need to be watered with milk. It's a more effective way of countering dehydration than a sports drink or water itself, say researchers at McMaster University.
That's particularly important during hot summer weather, says Brian Timmons, research director of the Child Health and Exercise Medicine Program at McMaster and principal investigator of the study.
"Children become dehydrated during exercise, and it's important they get enough fluids, particularly before going into a second round of a game. Milk is better than either a sports drink or water because it is a source of high quality protein, carbohydrates, calcium and electrolytes."
He added that milk replaces sodium lost in sweat and helps the body retain fluid better. As well, the milk provides protein needed by children for muscle development and growth which is not found in the other drinks.
The study of eight to 10-year-olds involved exercising in a climate chamber, then receiving a drink and being measured for hydration.
Timmons, an assistant professor of pediatrics of the Michael G. DeGroote School of Medicine, said active children and adults usually don't drink enough to stay hydrated during exercise, so they often have a "hydration disadvantage" when they start their next period of exercise.
He said that one per cent dehydration can have up to a 15 per cent decrease in performance, with an increased heart rate, core temperature and less ability to keep going. More significant dehydration comes with an increased risk of heat-related illness such as heat stroke.
Tuesday, August 16, 2011
15 minutes of moderate daily exercise lengthens life
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Health benefits of physical activity found to begin before people reach the half-hour standard
Taiwanese who exercise for 15 minutes a day, or 92 minutes per week, extended their expected lifespan by three years compared to people who are inactive, according to a study published today in The Lancet.
"Exercising at very light levels reduced deaths from any cause by 14 percent," said study senior author Xifeng Wu, M.D., Ph.D., professor and chair of The University of Texas MD Anderson Cancer Center Department of Epidemiology. "The benefits of exercise appear to be significant even without reaching the recommended 150 minutes per week based on results of previous research."
Lead author Chi-Pang Wen, M.D., of the National Health Research Institutes of Taiwan, and colleagues also found that a person's risk of death from any cause decreased by 4 percent for every additional 15 minutes of exercise up to 100 minutes a day over the course of the study. Those exercising for 30 minutes daily added about four years to life expectancy.
"These benefits were applicable to all age groups, both sexes and those with cardiovascular disease risk," the authors note.
If inactive people in Taiwan were to do low-volume daily exercise, one in six deaths could be postponed by their reduced risk of dying, the authors report. It would be an estimated reduction in mortality similar to that from a successful tobacco control program.
The prospective observational study involved 416,175 Taiwanese who participated in a standard medical screening program run by MJ Health Management Institution between 1996 and 2008. Participants were followed for an average of eight years.
For the exercise study, participants completed a questionnaire covering their medical history and lifestyle information. They characterized their weekly physical activity for the previous month by intensity -- light (walking), moderate (brisk walking), vigorous (jogging) or high vigorous (running) – and time.
To account for occupational effects, participants also characterized their physical activity at work, ranging from sedentary to hard physical labor.
Those who reported less than one hour a week of leisure time physical activity were classified as inactive – 54 percent of all participants. Others were classified as low, medium, high or very high based on the duration and intensity of their exercise. Researchers calculated mortality risk and life expectancy for each group.
Thirteen other variables were analyzed: age, sex, education level, physical labor at work, smoking, alcohol use, fasting blood sugar, systolic blood pressure, total cholesterol, body mass index, diabetes, hypertension and history of cancer.
Those who engaged in low-volume exercise had lower death rates than inactive people regardless of age, gender, health status, tobacco use, alcohol consumption or cardiovascular disease risk.
The researchers note that the World Health Organization and the U.S. Centers for Disease Control and Prevention recommend at least 150 minutes of moderate-intensity exercise per week. A third of U.S. adults meet that guideline; about 20 percent of adults in China, Japan or Taiwan meet it.
"A recommendation of 15 minutes of daily exercise should be promoted to East Asian populations," the authors note.
The study's findings of reduced mortality through even moderately intense exercise are likely to hold true for other populations, Wu said, even though the total amount of time spent or workout intensity required for a health benefit might differ. "These findings can stimulate people to exercise as much as they can and to not be frustrated that they can't reach the 30 minute per day guideline."
Health benefits of physical activity found to begin before people reach the half-hour standard
Taiwanese who exercise for 15 minutes a day, or 92 minutes per week, extended their expected lifespan by three years compared to people who are inactive, according to a study published today in The Lancet.
"Exercising at very light levels reduced deaths from any cause by 14 percent," said study senior author Xifeng Wu, M.D., Ph.D., professor and chair of The University of Texas MD Anderson Cancer Center Department of Epidemiology. "The benefits of exercise appear to be significant even without reaching the recommended 150 minutes per week based on results of previous research."
Lead author Chi-Pang Wen, M.D., of the National Health Research Institutes of Taiwan, and colleagues also found that a person's risk of death from any cause decreased by 4 percent for every additional 15 minutes of exercise up to 100 minutes a day over the course of the study. Those exercising for 30 minutes daily added about four years to life expectancy.
"These benefits were applicable to all age groups, both sexes and those with cardiovascular disease risk," the authors note.
If inactive people in Taiwan were to do low-volume daily exercise, one in six deaths could be postponed by their reduced risk of dying, the authors report. It would be an estimated reduction in mortality similar to that from a successful tobacco control program.
The prospective observational study involved 416,175 Taiwanese who participated in a standard medical screening program run by MJ Health Management Institution between 1996 and 2008. Participants were followed for an average of eight years.
For the exercise study, participants completed a questionnaire covering their medical history and lifestyle information. They characterized their weekly physical activity for the previous month by intensity -- light (walking), moderate (brisk walking), vigorous (jogging) or high vigorous (running) – and time.
To account for occupational effects, participants also characterized their physical activity at work, ranging from sedentary to hard physical labor.
Those who reported less than one hour a week of leisure time physical activity were classified as inactive – 54 percent of all participants. Others were classified as low, medium, high or very high based on the duration and intensity of their exercise. Researchers calculated mortality risk and life expectancy for each group.
Thirteen other variables were analyzed: age, sex, education level, physical labor at work, smoking, alcohol use, fasting blood sugar, systolic blood pressure, total cholesterol, body mass index, diabetes, hypertension and history of cancer.
Those who engaged in low-volume exercise had lower death rates than inactive people regardless of age, gender, health status, tobacco use, alcohol consumption or cardiovascular disease risk.
The researchers note that the World Health Organization and the U.S. Centers for Disease Control and Prevention recommend at least 150 minutes of moderate-intensity exercise per week. A third of U.S. adults meet that guideline; about 20 percent of adults in China, Japan or Taiwan meet it.
"A recommendation of 15 minutes of daily exercise should be promoted to East Asian populations," the authors note.
The study's findings of reduced mortality through even moderately intense exercise are likely to hold true for other populations, Wu said, even though the total amount of time spent or workout intensity required for a health benefit might differ. "These findings can stimulate people to exercise as much as they can and to not be frustrated that they can't reach the 30 minute per day guideline."
Moderate drinking protects against Alzheimer's and cognitive impairment
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Moderate social drinking significantly reduces the risk of dementia and cognitive impairment, according to an analysis of 143 studies by Loyola University Chicago Stritch School of Medicine researchers.
Researchers reviewed studies dating to 1977 that included more than 365,000 participants. Moderate drinkers were 23 percent less likely to develop cognitive impairment or Alzheimer's disease and other forms of dementia.
Wine was more beneficial than beer or spirits. But this finding was based on a relatively small number of studies, because most papers did not distinguish among different types of alcohol.
Results are reported in the journal Neuropsychiatric Disease and Treatment. The authors are Edward J. Neafsey, PhD. and Michael A. Collins, PhD., professors in the Department of Molecular Pharmacology and Therapeutics.
Heavy drinking (more than 3 to 5 drinks per day) was associated with a higher risk of cognitive impairment and dementia, but this finding was not statistically significant.
"We don't recommend that nondrinkers start drinking," Neafsey said. "But moderate drinking -- if it is truly moderate -- can be beneficial." Moderate drinking is defined as a maximum of two drinks per day for men and 1 drink per day for women.
Among the studies reviewed, 74 papers calculated the ratios of risk between drinkers and non-drinkers, while 69 papers simply stated whether cognition in drinkers was better, the same or worse than cognition in nondrinkers. Neafsey and Collins did a meta-analysis of the studies that calculated risk ratios and found that moderate drinkers were 23 percent less likely to develop dementia or cognitive decline.
Other findings:
The protective effect of moderate drinking held up after adjusting for age, education, sex and smoking.
There was no difference in the effects of alcohol on men and women.
The beneficial effect of moderate drinking was seen in 14 of 19 countries, including the United States. In 3 of the remaining 5 countries, researchers also found a benefit, but it was not strong enough to be statistically significant.
The findings were similar across different types of studies (longitudinal cohort studies, case-control studies and cross-sectional studies).
It is unknown why moderate drinking can have a beneficial effect. One theory suggests that the well-known cardiovascular benefits of moderate alcohol consumption, such as raising good HDL cholesterol, also can improve blood flow in the brain and thus brain metabolism.
A second possible explanation involves "sick quitters." According to this theory, nondrinkers have a higher risk of cognitive impairment and dementia because the group includes former heavy drinkers who damaged their brain cells before quitting. But the analysis by Neafsey and Collins did not support this explanation. They found that in studies that excluded former heavy drinkers, the protective effect of moderate drinking still held up.
Neafsey and Collins suggest a third possible explanation: Small amounts of alcohol might, in effect, make brain cells more fit. Alcohol in moderate amounts stresses cells and thus toughens them up to cope with major stresses down the road that could cause dementia.
For people who drink responsibly and in moderation, there's probably no reason to quit. But because of the potential for alcohol to be abused, Neafsey and Collins do not recommend that abstainers begin drinking.
The researchers note that there are other things besides moderate drinking that can reduce the risk of dementia, including exercise, education and a Mediterranean diet high in fruits, vegetables, cereals, beans, nuts and seeds. Even gardening has been shown to reduce the risk of dementia.
Moreover, there are times when people should never drink, including adolescence, pregnancy and before driving, the researchers said.
Moderate social drinking significantly reduces the risk of dementia and cognitive impairment, according to an analysis of 143 studies by Loyola University Chicago Stritch School of Medicine researchers.
Researchers reviewed studies dating to 1977 that included more than 365,000 participants. Moderate drinkers were 23 percent less likely to develop cognitive impairment or Alzheimer's disease and other forms of dementia.
Wine was more beneficial than beer or spirits. But this finding was based on a relatively small number of studies, because most papers did not distinguish among different types of alcohol.
Results are reported in the journal Neuropsychiatric Disease and Treatment. The authors are Edward J. Neafsey, PhD. and Michael A. Collins, PhD., professors in the Department of Molecular Pharmacology and Therapeutics.
Heavy drinking (more than 3 to 5 drinks per day) was associated with a higher risk of cognitive impairment and dementia, but this finding was not statistically significant.
"We don't recommend that nondrinkers start drinking," Neafsey said. "But moderate drinking -- if it is truly moderate -- can be beneficial." Moderate drinking is defined as a maximum of two drinks per day for men and 1 drink per day for women.
Among the studies reviewed, 74 papers calculated the ratios of risk between drinkers and non-drinkers, while 69 papers simply stated whether cognition in drinkers was better, the same or worse than cognition in nondrinkers. Neafsey and Collins did a meta-analysis of the studies that calculated risk ratios and found that moderate drinkers were 23 percent less likely to develop dementia or cognitive decline.
Other findings:
The protective effect of moderate drinking held up after adjusting for age, education, sex and smoking.
There was no difference in the effects of alcohol on men and women.
The beneficial effect of moderate drinking was seen in 14 of 19 countries, including the United States. In 3 of the remaining 5 countries, researchers also found a benefit, but it was not strong enough to be statistically significant.
The findings were similar across different types of studies (longitudinal cohort studies, case-control studies and cross-sectional studies).
It is unknown why moderate drinking can have a beneficial effect. One theory suggests that the well-known cardiovascular benefits of moderate alcohol consumption, such as raising good HDL cholesterol, also can improve blood flow in the brain and thus brain metabolism.
A second possible explanation involves "sick quitters." According to this theory, nondrinkers have a higher risk of cognitive impairment and dementia because the group includes former heavy drinkers who damaged their brain cells before quitting. But the analysis by Neafsey and Collins did not support this explanation. They found that in studies that excluded former heavy drinkers, the protective effect of moderate drinking still held up.
Neafsey and Collins suggest a third possible explanation: Small amounts of alcohol might, in effect, make brain cells more fit. Alcohol in moderate amounts stresses cells and thus toughens them up to cope with major stresses down the road that could cause dementia.
For people who drink responsibly and in moderation, there's probably no reason to quit. But because of the potential for alcohol to be abused, Neafsey and Collins do not recommend that abstainers begin drinking.
The researchers note that there are other things besides moderate drinking that can reduce the risk of dementia, including exercise, education and a Mediterranean diet high in fruits, vegetables, cereals, beans, nuts and seeds. Even gardening has been shown to reduce the risk of dementia.
Moreover, there are times when people should never drink, including adolescence, pregnancy and before driving, the researchers said.
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