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Shifting Gears On Supplements

Shifting Gears On SupplementsAccording to Tufts nutrition scientists Alice Lichtenstein and Robert Russell, research into individual nutritional supplements is a "double-edged sword" that should be wielded carefully.

Boston [08.24.05] Could an increased focus on supplements be drawing attention away from the need for a healthy diet? Alice Lichtenstein, DSc, and Robert Russell, MD, of Tufts' USDA Human Nutrition Research Center on Aging say yes, outlining their concerns in the July 20, 2005, edition of the Journal of the American Medical Association.

"There are insufficient data to justify an alteration in public health policy from one that emphasizes a food-based diet to fulfill nutrient requirements and promote optimal health outcomes to one that emphasizes dietary supplementation," they wrote in JAMA.

What is publicly said about the role of supplements in a healthy diet can have wide-ranging effects, according to the Tufts experts.

"If the message perceived is that nutrient supplements provide an 'insurance policy' against an imperfect diet, we must consider what impact this message would have on the balance of food choices and, hence, overall nutritional status," they cautioned. "Absent from the general population’s consciousness is a consideration for the cumulative effect of multiple fortified foods on daily nutrient intake or the combination of these fortified foods with a multivitamin supplement."

While science has made great strides in isolating nutrients for consumption both as food additives and supplements, Lichtenstein and Russell – senior scientists at the HNRCA and professors at Tufts' Friedman School of Nutrition Science and Policy and School of Medicine – warned that such progress has the potential to backfire.

"This advance has been a double-edged sword," they wrote. "It has allowed scientists to uncover the mechanisms by which nutrients sustain life and to quickly and inexpensively treat nutritional deficiencies. However, it has also allowed the possibility that the proper balance of purified vitamins and minerals could supplant the need for a varied diet to support life."

Several studies have demonstrated the inability to rely on nutritional supplements as key factors in preventing or treating disease. The authors note multiple examples, including the debunking of the once-touted connection between vitamin E and the prevention of heart disease and another in which beta carotene was disproven to play a role in reducing the risk of lung cancer.

"Instead of focusing on dietary patterns, most intervention trials have used high doses of single nutrients or nutrient cocktails in an attempt to prevent, affect, or mitigate a disease, intermediate measures of assessing disease risk, or disease outcomes. These results for the most part have been disappointing," the researchers stated.

"The promise of high-dose vitamin pills has been increasingly contradicted by gold-standard scientific research," The Boston Globe wrote in August, citing the JAMA piece. and NBC also reported on the issues raised by Lichtenstein and Russell.

Additionally, the concentrated use of nutrients to treat or prevent certain ailments can sometimes have harmful consequences. According to studies cited by the Tufts researchers, excess vitamin E could increase the occurrence of autoimmune diseases, and too much folic acid could cause dementia. Too much intake of certain nutrients can also inhibit the absorption or breaking down of other nutrients.

"For reasons that scientists have yet to figure out, the body processes vitamins differently when they arrive in food than in pill form – probably because foods interact with each other in a way that may help nutrient absorption," the Globe explained. "So far, nutrition specialists said, scientists working in labs can't beat what nature does."

Lichtenstein believes that the healthcare community must be more prudent before touting high doses of single supplements as a panacea or replacement for good eating habits.

"We still have a lot to learn about the use of high doses of nutrients," she said. "The important point is to prevent the cart from getting in front of the horse; we need to validate the science before there is wide scale adoption by the general public... We can no longer automatically assume there will be no adverse consequences."
























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