March 31, 2006
Increased magnesium intake associated with lower risk of developing metabolic syndrome
A report published ahead of print online in the journal Circulation revealed that young adults who have a higher intake of magnesium experienced a reduced risk of developing metabolic syndrome compared to their peers whose intake of the mineral is low.
Researchers at Northwestern University in Chicago and their colleagues evaluated data from 4,637 men and women between the ages of 18 and 30 who did not have metabolic syndrome or diabetes at the beginning of the study. Food frequency questionnaires completed by the participants were evaluated for magnesium intake from diet and supplements. Metabolic syndrome was diagnosed if subjects developed three or more of the following conditions: fasting glucose greater than or equal to 6.1 micromoles per liter, systolic blood pressure greater than or equal to 130 or diastolic blood pressure greater than or equal to 85 mm Hg, waist circumference more than 88 centimeters (34.6 inches)for women or 103 centimeters (40.6 inches) for men, triglycerides greater than or equal to 1.7 millimoles per liter, and HDL cholesterol level less than 1.3 millimoles per liter for women or less than 1.04 millimoles per liter in men.
Six hundred eight individuals were diagnosed with metabolic syndrome over the course of the study. Having a greater intake of magnesium was associated with a lower risk of developing the syndrome in a dose-response manner. Men and women whose intake of magnesium was in the top one-fourth of participants experienced a 31 percent lower risk than those in the bottom fourth.
"To our knowledge, no longitudinal study or clinical trial on magnesium and metabolic syndrome has been reported," the authors note. "Will higher magnesium intake prevent people from developing metabolic syndrome, which leads to diabetes and coronary heart disease? Further studies, particularly well-designed trials, are warranted," they conclude.
March 29, 2006
Animal study finds lower risk of obesity in offspring of mice who consumed soy compound
The April 2006, issue of the journal Environmental Health Perspectives published the finding of Randy L. Jirtle and colleagues at Duke University that pregnant mice provided with a diet rich in the soy phytoestrogen known as genistein gave birth to offspring that experienced a lower risk of becoming obese. The discovery may explain why Asians, who consume relatively large amounts of soy, have less obesity than their western counterparts.
Dr Jirtle's team gave one group of Agouti mice a diet containing a concentration of genistein comparable with that received by humans who consume high soy diets, while a second group received a phytoestrogen-free diet. The diets were initiated before the mice were bred, and continued throughout pregnancy and lactation.
Mice born to mothers who did not receive genistein had a greater rate of obesity upon adulthood, and weighed approximately twice as much as mice born to genistein-fed mothers. The phenomenon was associated with the methylation of a gene called agouti at six sites near its regulatory region, which reduced its expression among mice whose mothers did not receive genistein.
Dr Jirtle, who is a professor of radiation oncology at Duke, commented, "We are increasingly finding that our parents' and even our grandparents' nutritional status and environmental exposures can regulate our future risk of disease. In other words, it may not only be the hamburgers and fries we are eating, but also what our parents consumed or encountered in the environment that predisposes us to various conditions."
"Our study demonstrates there are highly sensitive windows early in development when environmental exposures can permanently alter the offspring's adult susceptibility to disease," he concluded. "Therefore, we need to examine the effect of environmental exposures during pregnancy, not just in adulthood, if we want to accurately assess their risk or benefit to humans."
March 27, 2006
Clinical trial finds grape seed extract lowers blood pressure
A study presented at the American Chemical Society Meeting and Exposition on March 26 in Atlanta found that men and women with the cluster of cardiovascular disease risk factors known as metabolic syndrome experienced a reduction in blood pressure after consuming grape seed extract. The trial was the first to assess grape seed's effect metabolic syndrome patients. The finding will also be reported on April 2 at the Federation of American Societies for Experimental Biology's 2006 meeting which will be held in San Francisco.
Cardiovascular researchers at the University of California, Davis divided 24 male and female metabolic syndrome patients into three groups of eight subjects each. One group was given a placebo, while the second and third groups received 150 and 300 milligrams of a grape seed extract for one month. Blood pressure was automatically measured and recorded for twelve 12 hours following ingestion.
"Participants in the two groups receiving grape seed extract experienced an equal degree of reduced blood pressure," reported lead researcher and professor of cardiovascular medicine at UC Davis, C. Tissa Kappagoda. "The average drop in systolic pressure was 12 millimeters. The average drop in diastolic pressure was 8 millimeters."
Additionally, participants who received the higher dose of grape seed extract experienced a reduction in serum oxidized low density lipoprotein cholesterol levels. "Generally, the higher their initial oxidized LDL level was, the greater the drop by the end of the study," Dr Kappagoda noted.
Dr Kappagoda's team previously found that grape seed extract helped prevent atherosclerosis in an animal model of the disease. A second placebo-controlled clinical trial has begun at UC Davis to determine the benefits of grape seed extract on patients with prehypertension.
March 24, 2006
Older can be better
The results of a study published in the April, 2006 issue of the Journal of Epidemiology and Community Health found that quality of life improved with age for many older individuals, contradicting the commonly held notion that life gets worse with age.
Dr Gopal Netuveli from Imperial College London and his British and Swedish colleagues evaluated health, social and socioeconomic factors among 12,234 men and women between the ages of 50 and 84 who participated in the English Longitudinal Study of Ageing. Responses to a 19 item scaled index were used for the analysis.
Not surprisingly, it was discovered that quality of life was reduced by depression, poor financial situation, mobility limitations, difficulties with the activities of daily living, and long-standing illness. Trusting relationships with family and friends, frequent contact with friends, living in a good neighborhood, and having two cars were all associated with improved quality of life.
Dr Netuveli commented, "Although many worry that old age and retirement could be a time of hardship, this study shows that for many their quality of life actually improves as they get older. In particular, social engagement such as volunteering can significantly improve quality of life, even in very old age."
Senior researcher, Professor David Blane, also from Imperial College, added, "An increasingly ageing population has raised the possibility of a 'long and morbid winter' for many old people, and a potential problem for national economies with more people to support than there are people to work. However this study indicates that many of the problems associated with old age may be compressed to the last few years and people are able to lead a fulfilling life after retirement."
March 22, 2006
Bing cherries lower inflammatory markers
The April, 2006 issue of the Journal of Nutrition published the findings of researchers at the U.S. Department of Agriculture that consuming Bing sweet cherries on a regular basis is appears to lower some inflammatory markers in men and women.
Researchers at the USDA's Western Human Nutrition Research Center in California and the University of California, Davis, enrolled eighteen healthy men and women for the current study. During a baseline period of eight days, the participants' blood was analyzed for the inflammatory markers serum C-reactive protein (CRP), plasma interleukin-6 and tumor necrosis factor-alpha, as well as plasma concentrations of nitric oxide (NO) and 42 inflammatory cytokines, receptors, growth factors, chemokines and adhesion markers. Additionally, total, VLDL, LDL and HDL cholesterol and subfractions as well as triglycerides were measured. The subjects were instructed to consume 280 grams Bing cherries per day for 28 days, during which blood samples were taken after two and four weeks and analyzed for the above factors. An additional blood sample was drawn and analyzed four weeks after the study's conclusion.
After one month of cherry consumption, C-reactive protein levels decreased by an average of 25 percent. The chemokines known as RANTES, and nitric oxide levels were also reduced. This effect continued for another month for RANTES, with levels decreasing even further to 36 percent below that of pre-study levels. Interleukin-6 and plasma lipid levels did not change during the study.
"Reduction in plasma CRP by cherries can be viewed as a reduction in inflammation that may affect the risk for CVD," the authors write. "This is supported by the simultaneous reductions in the ciruclating concentrations of NO and RANTES."
They note, "Because fresh cherries have limited availability, studies with cherry juice, canned cherries, cherry powder, or other fruits with similar phytochemical profile may be useful."
March 20, 2006
Ginseng use associated with improved survival among breast cancer patients
An advance online publication in the American Journal of Epidemiology revealed that among a sample of women with breast cancer who regularly use the popular herb ginseng there was improved survival and quality of life. Ginseng contains compounds known as ginsenosides which have been found to have anti-tumor effects in cell and animal studies, suggesting that the herb could be helpful for cancer patients.
Xiao-Ou Shu, MD, PhD and colleagues at Vanderbilt-Ingram Cancer Center at Vanderbilt University in Nashville evaluated ginseng's effects on 1,455 breast cancer patients who enrolled in the Shanghai Breast Cancer Study between August 1996 and March 1998 in Shanghai, China, and who were followed through December of 2002. All of the patients had been treated with surgery, chemotherapy and/or radiation. Information on ginseng use prior to diagnosis was obtained upon enrollment.
Three to four years following their diagnosis, the participants were asked by the researchers about their current ginseng use. While 27.4 percent of the patients had reported regular use of ginseng before their breast cancer diagnosis, 62.8 percent reported using the herb after being diagnosed. Ginseng use before diagnosis was correlated with improved survival, with those whose used the herb experiencing a 29 percent lower risk of mortality than those who did not use ginseng. Mortality from breast cancer and reccurence of the disease was similarly reduced. Ginseng use following diagnosis was found to have a positive association with reported physical, psychological, social and material well-being.
"There is a lot of skepticism about herbal medicine," Dr Shu stated. "That is why we are taking the observational approach at this time to see whether there is any efficacy. If so, we can go to the next phase... and eventually go to clinical trials."
March 17, 2006
Prostate cancer cells are wusses when it comes to hot chilies
Prostate cancer cells would rather commit suicide than feel the burn of hot chili peppers (or, at least, one of chili peppers' components), according to a report published in the March 15, 2006 issue of Cancer Research. Scientists at the Samuel Oschin Comprehensive Cancer Institute at Cedars-Sinai Medical Center along with colleagues from the University of California at Los Angeles found that giving capsaicin, the compound in jalapeño chilies responsible for a burning sensation when consumed, to mice in whom human prostate cancer tumors were implanted caused approximately 80 percent of the cancerous cells to undergo apoptosis (programmed self-destruction). The dose given to the mice was the equivalent of giving a 200 pound man 400 milligrams capsaicin three times per week, which is the amount provided by three to eight fresh habañera peppers.
In separate studies using androgen-dependent and independent cell cultures, capsaicin reduced cell proliferation and lowered the production of prostate specific antigen (PSA), a protein produced by prostate tumors.
"Capsaicin had a profound anti-proliferative effect on human prostate cancer cells in culture," stated study coauthor Sören Lehmann, MD, PhD, who is a visiting scientist at Cedars-Sinai Medical Center and the UCLA School of Medicine. "It also dramatically slowed the development of prostate tumors formed by those human cell lines grown in mouse models."
The team discovered that that capsaicin inhibited the the activation of NF-kappa Beta, a molecule involved in cell growth. "When we noticed that capsaicin affected NF-kappa Beta, that was an indication that we might expect some of the apoptotic proteins to be affected," commented senior author and director of Hematology and Oncology at Cedars-Sinai Medical Center, Phillip Koeffler, MD.
"In summary, our data suggests that capsaicin, or a related analogue, may have a role in the management of prostate cancer," the authors conclude.
March 15, 2006
Greater intake of calcium reduces colorectal cancer risk in men
The March, 2006 issue of the American Journal of Clinical Nutrition published the findings of S. C. Larsson of the Karolinska Instutet in Stockholm, Sweden and colleagues that men whose diets provide higher amounts of calcium and dairy foods have a lower risk of colorectal cancer.
The researchers enrolled 45,306 men with no history of cancer who were between the ages of 45 and 79 in 1997, and followed them for an average of 6.7 years. Food frequency questionnaires completed by the participants at the beginning of the study were analyzed for calcium and dairy product intake. During the follow-up period there were 276 cases of colon cancer and 173 cases of rectal cancer diagnosed.
Men whose calcium intake was in the top one-fourth of participants had a 32 percent lower risk of developing colorectal cancer than those whose intake was in the bottom fourth. The reduction in risk did not vary significantly with the site of the cancer. For dairy foods, consuming seven or more servings per day reduced the risk to 54 percent below that of men whose intake was less than two servings per day. Dairy foods appeared to have the greatest protective effect on the proximal colon. Milk emerged as the dairy food most strongly associated with a reduced risk of colorectal cancer, possibly because it is the most important source of dietary calcium intake in Sweden. Additionally, milk provides conjugated linoleic acid, sphingolipids and lactoferrin, all of which have been demonstrated to help prevent colorectal cancer in animals. The authors write. "Future studies should examine the relation of other components of dairy foods, such as conjugated linoleic acid, sphingolipids, and milk proteins, with the risk of colorectal cancer."
March 13, 2006
Cholesterol-lowering food combination as effective as drug intervention for some
A report published in the March, 2006 issue of the American Journal of Clinical Nutrition found that consuming a combination of cholesterol-lowering foods reduced low-density lipoprotein (LDL) cholesterol similarly to a statin drug.
Professor David Jenkins and colleagues at the University of Toronto prescribed diets containing high amounts of plant sterols, soy protein, viscous fibers and almonds to 66 men and women with elevated lipids. Fifty-five participants completed the twelve month study. Prior to the current study, 29 of the subjects had completed a short trial involving statin drugs.
The subjects maintained dietary records and had their cholesterol levels measured every two months by the researchers. At the study's conclusion, 31.8 percent of the participants had lowered their LDL-cholesterol by more than 20 percent, a reduction comparable to that achieved with statins in the earlier trial. Better compliance to the diet was correlated with a greater reduction in LDL-cholesterol, with only 2 of the 26 participants whose compliance was less than 55 percent having reduced their LDL by more than 20 percent by the end of the current study.
"Previous studies have demonstrated that statins can reduce heart disease risk between 25 and 50 per cent," Dr Jenkins stated. "We don't, however, know the long-term effects of these drugs when used on a large section of the broader population who are at low risk in primary prevention. Taking a pill may give people the false impression that they have nothing further to do to protect their health and prevent them from making serious lifestyle changes. Emphasizing diet changes in general can boost the success rate of statins while providing additional health benefits and a possible alternative for those for whom drugs are not a viable option."
March 10, 2006
Calcium supplements prevent pregnancy complications
The March, 2006 issue of the American Journal of Obstetrics and Gynecology published the findings of a World Health Organization randomized trial that a daily calcium supplement helps prevent complications associated with preeclampsia among pregnant women whose intake of the mineral is low. Preeclampsia is a condition that can occur during pregnancy which is characterized by high blood pressure and protein in the urine, and can lead to life-threatening complications for both mother and child.
The double-blind, placebo-controlled trial was conducted at prenatal care centers in Argentina, Egypt, India, Peru, South Africa and Vietnam, and included more than 8,300 pregnant women whose dietary intake of calcium was less than 600 milligrams per day, which is 50 percent of the amount recommended during pregnancy. Half of the participants were given 1500 milligrams calcium per day, while the remainder received a placebo.
While the incidence of preeclampsia did not differ between the two groups, eclampsia and other severe complications including severe gestational hypertension were significantly lower among those who received calcium. Preterm and early preterm delivery were reduced by calcium in women under the age of twenty, a group that is at greatest risk of being deficient in the mineral and experiencing the resulting complications. Additionally, children of women who received calcium had a lower rate of death.
Coauthor Jose Villar, MD, states, "This large randomized trial in populations with low calcium intake demonstrates that while supplementation with 1.5 gm calcium/day did not result in a statistically significant decrease in the overall incidence of preeclampsia, calcium significantly decreased the risk of its more serious complications, including maternal and severe neonatal morbidity and mortality, as well as preterm delivery, the latter among young women."
March 8, 2006
Higher omega-3 fatty acid levels correlated with better mood
A study funded by the National Heart, Lung and Blood Institute of the National Institutes of Health, reported at the 64th Annual Scientific Meeting of the American Psychosomatic Society held in Denver on March 6, 2006, found that people who have higher blood levels of omega-3 polyunsaturated fatty acids are more likely to report a positive mood. Omega-3 fatty acids are abundant in fish and fish oils, as well as flaxseeds, walnuts and other plant foods. Research has continued to reveal an array of benefits associated with their intake, although the majority of the studies have focused on their cardiovascular effects.
Sarah Conklin, PhD and colleagues at the University of Pittsburgh School of Medicine measured blood levels of omega-3 fatty acids in 106 healthy participants who were not asked to change their diets. Separate tests for depression, personality and impulsiveness were administered to all participants.
The researchers found that subjects with low omega-3 levels reported more mild to moderate symptoms of depression, a more negative outlook, and greater impulsivity. Those whose levels of the fatty acids were higher were discovered to be more agreeable.
Dr Conklin, who is a postdoctoral scholar with the Cardiovascular Behavioral Medicine Program at the University of Pennsylvania School of Medicine's department of psychiatry, commented, "A number of previous studies have linked low levels of omega-3 to clinically significant conditions such as major depressive disorder, bipolar disorder, schizophrenia, substance abuse and attention deficit disorder. However, few studies have shown that these relationships also occur in healthy adults. This study opens the door for future research looking at what effect increasing omega-3 intake, whether by eating omega-3 rich foods like salmon, or taking fish-oil supplements, has on people's mood."
March 1, 2006
Vitamin D plus calcium reduces falls in women
The results of a three year randomized controlled trial published in the February 27 2006 issue of the American Medical Association journal Archives of Internal Medicine found that long-term supplementation with vitamin D and calcium reduces the risk of falls in older women. The combination did not appear to influence falls in older men.
Heicke A. Bischoff-Ferrari, MD, of University Hospital Zurich, Switzerland and colleagues at Harvard School of Public Health and Tufts University analyzed data from 199 men and 246 women aged 65 and older enrolled in a study designed to show the effect of vitamin D and calcium on bone density. Participants received 500 milligrams calcium citrate malate with 700 international units vitamin D in the form of cholecalciferol, or a placebo for three years. Three hundred-eighteen participants completed their course of treatment.
At the study's conclusion, 45 percent of the men and 55 percent of the women reported one or more falls. The vitamin D and calcium combination was found to reduce the odds of falling among active women by 46 percent compared to those who received the placebo. Among women classified as less physically active, vitamin D and calcium supplementation was associated with a 65 percent reduction in falls, and for women who completed treatment throughout the three year follow-up, the risk was further reduced. For men enrolled in the study, the number reporting at least one fall in the treatment and placebo groups was almost the same. Activity level among men did not appear to influence responsiveness to treatment.
"Our results have clinical significance," the authors conclude. "We show a significant reduction in the odds of falling in ambulatory older women with a very inexpensive, well-tolerated, and simple supplementation with cholecalciferol-calcium."