Antioxidant Pills Block Metabolic Improvements
December 1, 2009
Walk into any commercial supplement store and you’ll find shelves of product aimed specifically at body-builders and other athletes.Among them: antioxidant supplements that promise to neutralize the free radicals generated by strenuous exercise.Unfortunately, if you swallow such pills — and claims — new research suggests you’re not only squandering money, you’re forgoing specific exercise benefits such supplements block.In a recent German study, 40 young male volunteers engaged in about an hour and a half of intense exercise — running, cycling, weight-lifting — five days a week.As expected, the regimen yielded various health benefits, including improved ability to control blood sugar, thus reducing diabetes risk.But when the men took antioxidant supplements — 400 IU of vitamin E and 1,000 mg of vitamin C — there was NO improvement in insulin sensitivity.Why? The pills seem to displace the body’s own natural antioxidant systems, which otherwise neutralize the oxidative damage caused by oxygen radicals produced during exercise.These findings add to the mountain of evidence that reliance on supplements either offers no benefits or even poses specific health risks. For example, athletes and others take glucosamine to relieve joint pain, but research shows most commercial supplements are ineffective, while the safety of large doses remains uncertain.Bromelain is another supplement aimed at joint health — but our lab work at the Dole Nutrition Institute found that fresh and frozen pineapple offer a natural source of the enzyme.
More disturbing, high intake of multivitamins in general — and zinc in particular — hiked men’s risk of dying from prostate cancer.Multis can also be a concern for women, as they’re linked to increased breast density, which can mean a six-fold greater breast cancer risk.Take Home Message: For maximum benefits and minimum risk, get the nutrients you need from apples, berries, broccoli, cauliflower and cabbage..