June 29, 2007
Lifestyle changes in middle age still beneficial
A report published in the July 2007 issue of The American Journal of Medicine concluded that adopting lifestyle changes relatively late in life is still an effective means to lower the risk of cardiovascular disease and lengthen life.
Dana E. King, MD, MS, along with Arch G. Mainous III, PhD, and Mark E. Geesey, MS at the Medical University of South Carolina in Charleston studied 15,792 men and women aged 45 to 64 who enrolled in the Atherosclerosis Risk in Communities Study (ARIC) between 1987 to 1989. The study was conducted by the National Heart Lung and Blood Institute to investigate the origin and progression of atherosclerotic diseases. Follow up visits were scheduled every three years through 1998 to obtain updated information on the participants' weight, medical history, diet, smoking status and exercise levels.
The researchers found that only 8.4 percent of the over-45 population newly adopted four healthy behaviors: consuming five or more fruits and vegetables daily, exercising a minimum of 2.5 hours per week, maintaining their body mass index (BMI) between 18.5 and 30 kilograms per meter, and not smoking. This group experienced a 35 reduction in the incidence of cardiovascular disease and a 40 percent reduction in mortality over the follow-up period compared with participants who adopted three or fewer behaviors.
“The potential public health benefit from adopting a healthier lifestyle in middle age is substantial," the authors conclude. "The current study demonstrated that adopting four modest healthy habits considerably lowers the risk of cardiovascular disease and mortality in relatively short-term 4-year follow up period. The findings emphasize that making the necessary changes to adhere to a healthy lifestyle is extremely worthwhile, and that middle-age is not too late to act.”
June 27, 2007
Review confirms association between depression and folate deficiency
A review published in the July, 2007 issue of the Journal of Epidemiology and Community Health determined that reduced folate, a member of the B vitamin complex, is associated with a greater risk of depression. Although the relationship had been previously observed in a number of studies, the association was not considered conclusive.
Dr Simon Gilbody and colleagues at the University of York and Hull York Medical School in England selected three case-control studies (in which patients diagnosed with depression were compared with a control population), seven population surveys, and one cohort study with a fifteen year follow-up period for the meta-analysis. The cohort study and one cross-sectional survey determined low folate from dietary records, while the remainder used serum or red blood cell folate levels.
The studies included a total of 15,315 participants, 1,769 of whom were diagnosed with depression. Adjusted analysis found that low folate status was associated with a 42 percent greater depression risk.
Folate is necessary for the formation of S-adenosylmethionine (SAMe) from homocysteine, as well as for the synthesis of neurotransmitters such as serotonin, which could help explain its effect on mood. Previous research conducted by the team determined that depressed individuals frequently have a gene that causes less efficient processing of folate.
"Our study is unique in that for the first time all the relevant evidence in this controversial area has been brought together," Dr Gilbody commented. "Although the research does not prove that low folate causes depression, we can now be sure that the two are linked. Interestingly, there is also some trial evidence that suggests folic acid supplements can benefit people with depression. We recommend that large trials should be carried out to further test this suggestion."
June 25, 2007
Men with low vitamin B6 intake have a greater risk of colorectal cancer
The July, 2007 issue of the Journal of Nutrition published a report by researchers in Japan that found an association between reduced vitamin B6 intake and an increased incidence of colorectal cancer.
Shoichiro Tsugane of Japan's National Cancer Center and his associates utilized data from the Japan Public Health Center-based Prospective Study Group, an ongoing cohort study of cancer, cardiovascular disease and other lifestyle diseases among the residents of 11 areas in Japan. The current study included 38,107 men and 43,077 women who responded to five-year follow-up surveys between 1995 and 1999. Food frequency questionnaires included in the surveys were used to estimate folate, vitamin B6, vitamin B12, and methionine intake. The authors hypothesize that low intake of these nutrients could cause colon cancer by inducing aberrations in DNA methylation and synthesis.
Participants were followed through 2002, during which 335 men and 191 women developed cancer. Men whose intake of vitamin B6 was in the top 25 percent of subjects had an approximately 35 percent lower risk of colorectal cancer than men in the lowest quarter. Among men in the lowest 25 percent of B6 intake, drinking more than 150 grams alcohol per week doubled the risk of colorectal cancer compared to men who drank less, however, a greater intake of vitamin B6 reduced this risk. None of the vitamins examined were associated with a protective effect among women.
The authors state that a protective effect for vitamin B6 among those who drink alcohol is biologically plausible because alcohol interferes with B6 absorption, reduces the synthesis of methionine from homocysteine, and lowers glutathione levels. They conclude that a higher intake of the vitamin may be of benefit to those who consume more than 150 grams alcohol per week.
June 22, 2007
Omega-3 fatty acids help relieve depression and agitation for some Alzheimer’s disease patients
A report published online on June 21, 2007 in the International Journal of General Psychiatry described the finding of researchers at Karolinska Institutet and Uppsala University in Sweden that supplementing with omega-3 fatty acids can help improve depression and agitation in men and women with Alzheimer’s disease. Agitation and/or depression are psychiatric symptoms that frequently occur in Alzheimer's disease patients along with cognitive dysfunction and brain changes. Epidemiologic studies have associated a greater intake of fatty fish, which contains abundant amounts of omega-3 fatty acids, with a protective effect against Alzheimer's disease.
Yvonne Freund-Levi of Karolinska University Hospital in Stockholm and colleagues divided 200 patients with mild Alzheimer's disease to receive 0.6 grams eicosapentaenoic acid (EPA) and 1.7 grams docosahexaenoic acid (DHA) per day, or a placebo for six months, followed by another six month period in which all participants received the omega-3 fatty acids. Neuropsychiatric symptoms, caregivers' burden, and activities of daily living were evaluated.
One hundred seventy-four participants completed the trial. Although there did not appear to be an overall difference between the effects of treatment with omega-3 fatty acids and the placebo group, patients that carried the Alzheimer's disease susceptibility gene APOE 4 were found to have a significant decrease in agitation after treatment with EPA and DHA, while depressive symptoms improved in noncarriers of the gene.
The study adds evidence to previous research suggesting an antidepressant effect associated with EPA and DHA. The authors note that larger studies involving participants with more pronounced neuropsychiatric symptoms are needed before general therapeutic recommendations can be made.
June 20, 2007
Less is more
A review published in the May 9, 2007 issue of the Journal of the American Medical Association revealed the finding of a group of cardiologists that baby aspirin may be just as effective at preventing cardiovascular events with less of a risk of gastrointestinal bleeding than adult-sized aspirin. Baby aspirin contains 75 to 81 milligrams aspirin in contrast with 325 milligrams in an adult dose. Earlier research has indicated that long term doses of as little as 30 milligrams per day are adequate to help prevent excessive blood clot formation, which can lead to heart attack or stroke.
Cardiologists at the University of Kentucky and the Institut de Cardiologie-Centre Hospitalier Universitaire Pitié-Salpêtrière in Paris selected 8 randomized controlled clinical trials and 3 observational studies for the current review. Analysis of the data failed to find support for using more than 75 to 81 milligrams aspirin, and confirmed an increased incidence of bleeding events associated with higher doses.
"While aspirin is an effective drug for the prevention of clots, the downside of aspirin therapy is an increased tendency for bleeding (particularly from the GI tract)," stated lead author Charles L. Campbell, MD of the University of Kentucky's Gill Heart Institute. "We believe the minimum effective dose should be utilized. We also believe more study in this area is warranted to determine if the minimum dose is effective for everyone, or if dose should be adjusted from person to person."
Coauthor Steven R Steinhubl, MD, also of the University of Kentucky, added, "Patients should check with their doctor to be sure, but there is almost no one who needs to take more than 81 mg of aspirin a day for protection from heart attacks."
June 15, 2007
Healthy diet and exercise improve breast cancer survival
The June 10, 2007 issue of the Journal of Clinical Oncology published the results of a study conducted by the Moores Cancer Center at the University of California, San Diego that found a diet high in vegetables and fruit combined with exercise cuts the risk of dying by half among breast cancer survivors. The study is the first to evaluate the combination in breast cancer patients.
The subjects included 1,490 women aged 70 and younger enrolled in the ongoing Women's Health Eating and Living (WHEL) study. Participants were treated for early-stage breast cancer between 1991 and 2000, and enrolled an average of two years after their diagnosis.
Consuming at least five servings of vegetables and/or fruits per day combined with the exercise equivalent of thirty minutes six days per week of walking was associated with half the risk of dying over the 5 to 11 year follow-up period compared with women who did not adhere to these practices. The finding was valid for both obese and normal weight women, and stronger for those with hormone-receptor positive cancers.
"Of particular importance is that this halving of risk was seen in women who were not obese as well as in those who were obese,” coauthor Cheryl Rock, PhD, RD observed. “Also, the effect was not seen in women who practiced only one of the lifestyle patterns – high vegetable and fruit intake, or physical activity.”
“We demonstrate in this study of breast cancer survivors that even if a woman is overweight, if she eats at least five servings of vegetables and fruits a day and walks briskly for 30 minutes, six days a week, her risk of death from her disease goes down by 50 percent,” lead author John Pierce, PhD, of Moores Cancer Center concurred. “The key is that you must do both.”
June 13, 2007
Greater vitamin D levels associated with protection from cardiovascular risk factors
A report published in the June 11, 2007 issue of the journal Archives of Internal Medicine concluded that having higher serum levels of 25-hydroxyvitamin D is associated with a lower risk of hypertension, diabetes, obesity, and elevated triglyceride levels, all risk factors for cardiovascular disease.
Researchers at Charles R. Drew University of Medicine and Science in Los Angeles and colleagues at the University of California, Los Angeles, and Harvard examined data obtained from 7,186 men and 7,902 women enrolled in the Third National Health and Nutrition Examination Survey (NHANES III), conducted from 1988 through 1994. Blood samples were tested for serum vitamin D, cholesterol, triglycerides, fasting blood glucose and other factors, and height, weight, body mass index, and blood pressure were determined. Interviews with the subjects confirmed pre-existing diabetes and hypertension.
Mean serum vitamin D levels, particularly in women, people aged 60 and older, and minorities, were well below the recommended national goal. The team found significant relationships between lower vitamin D levels and the presence of cardiovascular disease risk factors. Participants whose vitamin D levels were in the lowest one-fourth of the study population had a 30 percent greater risk of hypertension, a 98 percent higher risk of diabetes, more than double the risk of obesity, and a 47 percent greater risk of having high serum triglyceride levels than subjects whose vitamin D levels were in the top 25 percent.
The study is the first, to the authors' knowledge, to show a significant association between reduced vitamin D levels and risk factors for cardiovascular disease risk factors in a nationally representative sample. They conclude that "Prospective studies to assess a direct benefit of cholecalciferol (vitamin D) supplementation on cardiovascular disease risk factors are warranted."
June 11, 2007
Greater fruit, vegetable, vitamin intake linked with reduced mortality over six and a half year period
The June, 2007 issue of the American Journal of Clinical Nutrition published the finding of researchers in Spain that men and women who consumed a greater amount of fruits, vegetables and antioxidant nutrients experienced fewer deaths during a 6.5 year period.
Antonio Agudo of The Catalan Institute of Oncology in Spain and his associates evaluated data from 41,358 Spanish participants in the European Prospective Investigation Into Cancer and Nutrition study. Information on diet obtained during interviews was analyzed for alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, vitamin C, and vitamin E levels. Vegetable intake was grouped and analyzed in five categories, and fresh fruit was analyzed separately from total fruit consumption.
Over the 6.5 year follow-up, 562 deaths occurred among 30 to 69 year olds. Participants whose fresh fruit intake was in the top 25 percent of participants experienced a 21 percent lower risk of dying than those whose intake was in the lowest fourth. Root vegetable intake in the top fourth was associated with a 28 percent lower mortality risk, and seed-containing vegetables with a 23 percent lower risk compared with those whose intake was least.
When antioxidants were examined, lycopene intake was associated with the greatest reduction in the risk of death. Subjects whose lycopene intake levels were in the top fourth had a 35 percent lower risk of death during follow-up compared with men and women whose intake was in the bottom fourth. Vitamin C and carotenoids also appeared to be protective, however, adjustment for total antioxidant capacity in plant foods cancelled the effect.
"A high intake of fresh fruit, root vegetables, and fruiting vegetables is associated with reduced mortality, probably as a result of their high content of vitamin C, provitamin A carotenoids, and lycopene," the authors conclude. "Antioxidant capacity could partly explain the effect of ascorbic acid and provitamin A but not the association with lycopene."
June 8, 2007
Flaxseed arrests prostate tumor growth
The results of research presented on June 2, 2007 at the annual meeting of the American Society of Clinical Oncology in Chicago found that consuming flaxseed can help arrest the growth of tumors of the prostate gland.
The study involved men scheduled for removal of the prostate due to prostate cancer. Researchers at Duke University Medical Center assigned four groups of approximately 40 patients each to receive a low fat diet, a low fat diet supplemented with 30 grams ground flaxseed daily, an unsupplemented normal diet, or a normal diet combined with 30 grams ground flaxseed per day for one month prior to surgery.
Men in both groups that received flaxseed were found to have the slowest rate of tumor growth when the prostate tumors were examined following surgery. The omega-3 fatty acids in flaxseed are believed to halt the cellular activity that leads to cancer growth and spread by modifying the ability of cancer cells to clump together or adhere to other cells. Lignans from flaxseed might also help inhibit the ability of tumors to form new blood vessels.
"Our previous studies in animals and in humans had shown a correlation between flaxseed supplementation and slowed tumor growth, but the participants in those studies had taken flaxseed in conjunction with a low-fat diet," commented lead researcher Wendy Demark-Wahnefried, PhD of Duke's School of Nursing. "For this study, we demonstrated that it is flaxseed that primarily offers the protective benefit. The results showed that the men who took just flaxseed as well as those who took flaxseed combined with a low-fat diet did the best, indicating that it is the flaxseed which is making the difference," she explained.
"We are excited that this study showed that flaxseed is safe and associated with a protective effect on prostate cancer," Dr Demark-Wahnefried added.
June 6, 2007
Low testosterone linked to increased risk of dying over 18 year period for over-50s
The results of a study presented on June 5, 2007 at The Endocrine Society for publication in their ENDO 07 Research Summaries Book determined that men over 50 whose levels of the hormone testosterone are low had a greater risk of dying within an eighteen year period than men with higher levels.
University of California, San Diego School of Medicine chief of the Division of Epidemiology Elizabeth Barrett-Connor, MD and colleagues evaluated data from nearly 800 men aged 50 to 91 who enrolled in the Rancho Bernardo Heart and Chronic Disease Study in the 1970s. Twenty-nine percent of the participants had testosterone levels at the lower limit of the normal range for their age at the beginning of the 1980s. These men experienced a 33 percent greater risk of dying from any cause over the ensuing 18 years than men with higher levels. Participants with decreased testosterone had a greater incidence of elevated inflammatory cytokines, as well as greater waist girth and other metabolic syndrome risk factors.
"Conventional wisdom is that women live longer because estrogen is good and testosterone is bad," Dr Barrett-Connor stated. "We don’t know. Maybe the decline in testosterone is healthy and comes with older age. Maybe the decline is bad and is associated with chronic diseases of aging."
"The new study is only the second report linking deficiency of this sex hormone with increased death from all causes, over time, and the first to do so in relatively healthy men who are living in the community," announced coauthor Gail Laughlin, PhD, who presented the findings. "We have followed these men for an average of 18 years and our study strongly suggests that the association between testosterone levels and death is not simply due to some acute illness."
June 4, 2007
Meta-analysis finds folic acid supplements lower stroke risk
A meta-analysis published in the June 2, 2007 issue of The Lancet concluded that supplementing with the B vitamin folic acid can lower stroke risk by at least 18 percent.
Professor Xiaobin Wang of Children's Memorial Hospital and Children's Memorial Research Center at Northwestern University Feinberg School of Medicine in Chicago and analyzed eight randomized trials involving folic acid and stroke. The review concluded that participants supplementing with folic acid lowered their risk of stroke by an average of 18 percent compared to those who did not use folic acid supplements, however, for trials in which supplementation continued for at least three years, the risk was lowered to 29 percent.
It is believed that the reduction in homocysteine, an amino acid found in the blood that is toxic in above normal amounts, is responsible for folic acid's ability to lower the incidence of strokes as well as cardiovascular disease and deep vein thrombosis. In the current review, homocysteine reduction of 20 percent or more, having no prior risk of stroke, or living in areas in which folic acid fortification of grains was not mandated further increased the reduction in stroke risk found to be associated with folic acid supplementation.
"Our meta-analysis provides coherent evidence that folic acid supplementation can significantly reduce the risk of stroke in primary prevention," the authors conclude. "To efficiently assess the efficacy and causality of folic acid supplementation on stroke, future clinical trials should be done in regions without grain fortification, with a longer period of follow-up (4 years or longer), and among individuals without a history of stroke. The issue of folic acid supplementation alone versus folic acid in combination with other B vitamins, as well as optimum dosage, should also be carefully considered in future trials."
June 1, 2007
Flavonol improves mouse memory
The May 30, 2007 issue of The Journal of Neuroscience reported that a flavonol known as epicatechin that occurs in tea, blueberries and grapes improves memory in mice, an effect further enhanced by regular exercise.
Henriette van Praag, PhD, of the Salk Institute and colleagues gave one group of mice a standard diet and while another group received the diet supplemented with epicatechin for one month. Half of the mice in each group were provided with an exercise wheel for two hours per day. At the end of the treatment regimen, the animals were trained to locate a platform hidden underwater.
Although epicatechin was associated with better memory, blood vessel growth, and gene activity in nonexercising mice that received the compound, these effects were more pronounced in animals that had also access to exercise. Mice that received both epicatechin and exercise remembered the platform location for a longer period of time than the other groups, demonstrating improved spatial memory. The combination also resulted in structural and functional changes, such as an increase in mature nerve cells and blood vessel growth, in the part of the brain used during learning and memory known as the dentate gyrus, which suggests that the cells' ability to communicate was improved. Expression of genes involved in memory and learning increased, while the expression of those involved in inflammation and neurodegeneration was reduced.
"This finding is an important advance because it identifies a single natural chemical with memory-enhancing effects, suggesting that it may be possible to optimize brain function by combining exercise and dietary supplementation," commented Mark Mattson, PhD, of the National Institute on Aging.
Dr van Praag added that "A logical next step will be to study the effects of epicatechin on memory and brain blood flow in aged animals, and then humans, combined with mild exercise."
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