What's Hot
What's Hot
 |
|
April 2003
Intermittent fasting provides benefits of dietary restriction A study published in the Proceedings of the National Academy of Sciences online early edition has shown that a regimen of every other day fasting resulted in some benefits that met or exceeded those previously demonstrated to be the result of dietary restriction. Restricting calories in the diet has been the only method to consistently extend maximum lifespan in every species tested, and has been shown to provide other benefits such as lower glucose levels and improved disease resistance. The current study, conducted by researchers at the National Institute on Aging Gerontology Research Center, used nine week old mice that were divided into groups who received unlimited access to food, unlimited access every other day alternating with fasting, or a diet containing 60 percent of the calories consumed by the first group. Blood samples were drawn at 29 weeks of age. At the study’s conclusion, the intermittently fasting mice were consuming the same amount of food in a 48 hour period as the mice who were allowed to eat as much as they wanted. While body weight of the calorie restricted mice was half that of the group whose calories were unlimited, intermittently fasting mice weighed only slightly less. Both calorie restricted and intermittently fasting mice had significantly lower fasting levels of glucose and insulin, with levels in the intermittently fasting mice dropping lower than those of the calorie restricted group. Mice who fasted every other day also showed greater brain cell resistance to excitotoxic stress than either group. IGF-1 levels were reduced in the restricted mice but increased in the intermittently fasting mice, revealing a dissociation in the mechanisms that regulate IGF-1 and insulin levels. Although this study did not show whether intermittent fasting would extend lifespan, it demonstrated that the regimen has benefits that are independent of caloric intake. —D Dye Modified citrus pectin slows prostate cancer growth in new study A study published in the February 1 2003 issue of The Prostate that evaluated a new statistical method additionally confirmed previous research showing that oral consumption of modified citrus pectin (MCP) slowed the progression of prostate cancer in humans. The report was based on research conducted at the Prostate Cancer Research Institute and Healing Touch Oncology in Marina del Rey, California. Prior research had found that consuming modified citrus pectin lengthened prostate specific antigen doubling time in four of seven patients. Prostate specific antigen, or PSA, is a marker for prostate tumors and is monitored during prostate cancer treatment to aid physicians in evaluating treatment success. Shorter PSA doubling times indicate accelerated disease progression. In the current study, prostate cancer patients who experienced PSA elevation after prostatectomy, radiation or cryosurgery were given 15 grams of modified citrus pectin per day in three divided doses for one year. In 75 percent of the patients, modified citrus pectin slowed the progression of the cancer as indicated by PSA levels. Stephen Strum MD, who with Mark Scholz MD, conducted the previous study, commented, “Modified citrus pectin is a natural substance, it’s nontoxic and it has been shown to slow down the progression of prostate cancer. I recommend MCP selectively to patients who have a high risk of recurrence of prostate cancer after any primary treatment. I also recommend MCP for those who have shown a slow, persistent rise of PSA levels that is consistent with established prostate cancer recurrence.” Integrative medicine physician Isaac Eliaz, MD, whose Northern California practice focuses on cancer patients, noted that because subjects experienced a drop in PSA levels soon after treatment was initiated, the mechanism of action of MCP may not be solely that of inhibiting metastasis as has been hypothesized, and that an antiangiogenic effect for MCP may be at work. —D Dye Green tea compound is fountain of youth for skin cells In a study published online in the Journal of Pharmacology and Experimental Therapeutics, researchers from the Medical College of Georgia have discovered yet another health benefit for green tea: the ability to heal wounds and skin diseases. The research team, led by cell biologist Dr Stephen Hsu, studied the effect of epigallocatechin-3-gallate (EGCG), the most abundant polyphenol found in green tea, on growing and aging human epidermal skin cells. Previous research had found that the compound induced apoptosis (programmed cell death) in tumor cells. In the current study, the researchers found that EGCG accelerated cell differentiation in the growing cells and renewed DNA synthesis in the aged cells. Dr Hsu commented, "Cells that migrate toward the surface of the skin normally live about 28 days, and by day 20, they basically sit on the upper layer of the skin getting ready to die. But EGCG reactivates them. I was so surprised. When exposed to EGCG, the old cells found in the upper layers of the epidermis appear to start dividing again. They make DNA and produce more energy. They are reactivated. There are lots of unknowns-this is the first step into the door-but if we can energize dying skin cells, we can probably improve the skin condition.” Dr Hsu believes the finding is promising for conditions such as apthous ulcers, wrinkles, rosacea, psoriasis and wounds, and may also be of value for diabetics, who experience delayed healing. He explained, "If skin cells surrounding wounds or infections don't heal in time, fibroblasts in the connective tissue may rush in to fill the void and cause scar tissue formation. If we can spur the skin cells to differentiate and proliferate, we can potentially accelerate the wound-healing process and prevent scarring." —D Dye Tea boosts immune function A report published in the early online edition of The Proceedings of the National Academy of Sciences (http://www.pnas.org) has revealed that drinking tea can promote a strong immune response in humans. Tea contains L-theanine which is a precursor to nonpeptide alkylamine antigens that are also found in bacteria, parasites, fungi and tumor cells. Exposure to this antigen results in a memory response of the immune system in the event of subsequent exposure to one of the pathogenic agents. Using cultured human gamma-delta T cells, which are involved in immune response, researchers at Brigham and Women’s Hospital and Harvard Medical School in Boston exposed some of them to an alkylamine antigen, washed them, and then exposed the cells to the same antigen, dead bacteria, or lipopolysaccharide. Cells that had been exposed to the antigen multiplied up to ten-fold and produced the cytokines interferon-gamma or tumor necrosis factor-alpha, which help fight disease. Cells not exposed showed none of this response. Interestingly, the bacteria and lipopolysaccharide do not contain the antigen, demonstrating a nonmemory response elicited by antigen exposure. In a human investigation, eleven volunteers were asked to drink five to six cups of black tea (containing a total of 2.2 micromoles L-theanine) daily for two weeks or four weeks. A control group was instructed to drink the same amount of instant coffee. Blood samples were taken at the start of the study and at the end of each week. In the group that received tea, gamma-delta T cells showed an increase in the ability to produce chemicals that combat disease after two weeks, however this benefit was not observed in the gamma-delta T cells of the coffee drinkers. The authors conclude , "Dietary intake of tea . . . may prime human gamma-delta T cells that then can provide natural resistance to microbial infections and perhaps tumors.” —D Dye Whey, creatine increase muscle fiber growth In yet another exciting finding revealed at the 2003 Experimental Biology Meeting, cosponsored by the American Physiological Society, researchers at Victoria University in Australia have demonstrated that a 100% whey isolate formula and the popular athletic supplement creatine produce an increase in muscle fiber growth greater that correlated with greater strength gains. The same researchers had conducted earlier experiments that revealed an increase in muscle force and mitochondrial energy production in rats and improve muscle mass and strength in bodybuilders when either supplement was consumed. In the current double-blind study, the researchers, led by Professor Mick Carey and Dr Alan Hayes from Victoria University’s Centre for Rehabilitation, Exercise and Sport Science, supplemented thirty-three male bodybuilders with 1.5 grams per kilogram body weight with the following daily regimens: creatine plus carbohydrate, whey isolate, creatine and whey, or carbohydrate alone. The investigators took biopsies of the muscle fibers of the subjects before and following an eleven week period of thrice weekly resistance training, and found an increase in the cross sectional area of fast-twitch muscle fibers in men who consumed creatine and/or whey compared to the men who received the supplement consisting of carbohydrate. Fast twitch muscle fibers are those that grow in response to weight training and are responsible for maximal force production. Subjects who received both whey and creatine experienced a greater increase in fast twitch muscle fiber size than those who received whey alone. Additionally, a significant correlation between strength gains and increase in muscle type fiber was observed in the participants. While all groups gained in strength and lean mass after eleven weeks, the groups receiving creatine and/or whey experienced a greater increase than the carbohydrate only group. Whey is a protein that naturally occurs in cow’s milk. In addition to aiding bodybuilders and other athletes, whey may prove to be helpful to older individuals or others who experience muscle wasting conditions. —D Dye Grape seed extract lowers blood pressure In another promising study presented during the annual American Physiological Society meeting, researchers from the University of Alabama in Birmingham reported that an extract of grape seed given to spontaneously hypertensive female rats whose ovaries had been removed caused a reduction in blood pressure comparable to that of plant estrogens or estradiol, one of the hormones provided with hormone replacement therapy. Blood pressure often rises after menopause in women presumably due to the decline in estrogens, the principle hormones made by the ovaries. Postmenopausal women have frequently used hormone replacement therapy to control hypertension and other unwanted menopausal effects, but the use of this therapy has recently been found to be associated with an increased risk of cardiovascular events and reproductive system cancers. Previous research by the investigators uncovered a similar antihypertensive benefit from phytoestrogens derived from soy. In the current study, the researchers used three week old spontaneously hypertensive rats and surgically removed their ovaries to mimic menopause. The rats were provided with phytoestrogen-free diets containing 1 percent or 8 percent sodium chloride. Half of the rats received the addition of grape seed extract to their food. Predictably, the high (8 percent) salt diets greatly elevated blood pressure, however, the rats on this group who received grape seed extract experienced a much lower elevation. Rats on the 1 percent salt diet did not appear to be affected by grape seed extract. Like the estrogenic compounds, the extract did not produce any change in heart rate, showing a specific effect on blood pressure. The findings suggest that a different mechanism than estrogen receptor activation may be the cause of the benefits of estrogen therapy in postmenopausal hypertension. The researchers believe that the polyphenols from grape seed extract may be useful as an antihypertensive for women who are postmenopausal. —D Dye Alpha-lipoic acid helps reduce symptoms of diabetic neuropathy The March 2003 issue of the journal Diabetes Care published the results of a study showing that alpha-lipoic acid (ALA) improved symptoms such as burning, sharp pain, prickling sensations and numbness in diabetic patients. The study was the result of a collaboration between the Russian Medical Academy for Advanced Studies in Moscow and the Mayo Clinic. Diabetic sensorimotor neuropathy results from nerves damaged by oxidative stress that occurs with the high glucose levels experienced by patients who fail to adequately control the disease. One hundred twenty diabetic patients with neuropathy were enrolled in the study. One half were randomized to receive 600 milligrams alpha-lipoic acid intravenously while the remainder received a placebo, given periodically over three weeks After fourteen treatments, the Pain and Symptom Score of patients who received the alpha-lipoic acid improved by an average of 5.7 points compared to the placebo group’s improvement of 1.8 points. There were no unfavorable side effects experienced by the group receiving the alpha-lipoic acid. Research team member and Mayo Clinic neurologist Peter Dyck MD, commented, "There appears to be a rather large effect on the pain of diabetic neuropathy with ALA. The magnitude of the change is considerable. We also found some improvement in neurologic signs and nerve conduction. We were surprised by the magnitude and the rapidity of the response . . . I think it’s a promising lead for the future, in that antioxidants may be implicated in the cause of diabetic neuropathy, and ALA might conceivably be a preventative or interventative. It is known that ALA is a very strong antioxidant. High glucose in diabetes leaves trace chemicals harmful to cells -- that process is called oxidative stress. Antioxidants promote getting rid of oxidative stress products. “ Nutritional supplements reduce low birth weight incidence when given during pregnancy A study published in the March 15 2003 issue of the British Medical Journal has found that supplements containing folic acid and iron were just as effective as multiple micronutrient supplements in reducing the risk of low birth weight in newborn infants. The study was conducted in rural Nepal by researchers from with the Johns Hopkins Bloomberg School of Public Health's Center for Human Nutrition. Ninety percent of low birth weight infants are born in developing countries such as Nepal. Four thousand nine hundred twenty-six pregnant women were given vitamin A alone (control) or vitamin A with folic acid, folic acid plus iron, folic acid plus iron and zinc, or a supplement containing folic acid, iron, zinc, vitamin D, vitamin E, vitamin B1, vitamin B2, niacin, vitamin B6, vitamin B12, vitamin C, vitamin K, copper and magnesium. While folic acid alone and folic acid combined with iron and zinc had no effect on birth weight compared to the control group, the multiple micronutrient supplement reduced the incidence of low birth weight by 14 percent, and the folic acid-iron combination reduced it by 16 percent. Lead investigator and Center for Human Nutrition associate research professor Parul Christian DrPH, commented, "Our research work is aimed at trying to discern the right combinations of micronutrients that will maximize the health benefits to both mother and child . . . Micronutrient deficiencies during pregnancy may predispose mothers to losing their fetuses, having low birth weight newborns or infants who grow poorly. In rural Nepal alone, where more than 40 percent of babies are born low birth weight, a widespread micronutrient supplementation program could have a tremendous impact on the health and survival of millions of children." —D Dye Chromium picolinate safety, effectiveness reaffirmed The Council for the Advancement of Diabetes Research and Education Research (CADRE) Summit : Chromium in Health and Disease, was the site of presentations by several researchers on the subject of chromium picolinate. Chromium is an essential mineral that is often deficient in individuals consuming diets high in processed foods. Previous research has found that supplementation with chromium picolinate improves glucose tolerance in diabetics. The mineral, by enhancing the action of insulin, a hormone involved in carbohydrate, fat and protein metabolism, can help lower some of the risk factors for diseases associated with insulin resistance such as type 2 diabetes, obesity, cardiovascular disease, polycystic ovarian syndrome and atypical depression. CADRE co-chair and Associate Professor of Medicine at the University of Vermont College of Medicine, William T. Cefalu, MD, stated, "Prior human studies have suggested that chromium picolinate decreases insulin levels and improves blood sugar metabolism in both obese people and people with type 2 diabetes. This summit is important because not only will leading experts present relevant data regarding clinical observations with this nutrient, but precise studies assessing the mechanism of action will be presented." A review of scientific studies of chromium picolinate by the Institute of Medicine found no safety concerns for chromium at any of the amounts used. John Hathcock, PhD, vice president, scientific and international affairs of the Council for Responsible Nutrition commented, "This review included human studies of supplemental chromium (as chromium picolinate) up to 1000 micrograms per day and there were no observed adverse effects from intake of chromium, hence chromium picolinate is safe." —D Dye |
