For many years, Americans believed antioxidants, such as vitamins A, C and E, along with beta-carotene, could help prevent heart disease, cancer, senility and even the aging process itself. Millions of Americans now take various antioxidant supplements hoping they can largely counteract the negative health effects of a diet rich in refined carbohydrates, saturated fats, hydrogenated fats, and salt.

Certainly there have been many studies showing that people taking anti-oxidant supplements were at a lower risk for various diseases and even some suggesting that they may live longer. Problem is, these population studies can often be misleading. People taking antioxidant supplements were on average less likely to smoke, more likely to exercise, and more likely to eat a healthy diet. Obviously such lifestyle factors, rather than the supplements themselves, could explain the correlation seen with less disease and anti-oxidant supplements.The way to get around this bias is randomized, double blind clinical trials. Here people are randomly assigned to either take an antioxidant supplement or a look-a-like placebo. A recent systematic review and meta-analysis looked at 68 such trials with 232,606 subjects. When the researchers looked at the least biased 47 trials using various antioxidant supplements in various combinations they found that supplements of beta-carotene, vitamin E, and vitamin A all significantly increased the risk of dying. Vitamin C supplements were also associated with a modest increase in total mortality but this was not statistically significant. The only anti-oxidant supplement that showed any possible benefit was selenium but this was given in doses closer to the RDA than the vitamins.1 Bottom Line: Certainly for most people, high dose anti-oxidant supplements do not slow the aging process or dramatically cut the risk of serious disease. In high doses, many of these antioxidant combo supplements may actually hasten death. By contrast, a diet with plenty of fruits, vegetables, whole grains, and little salt, fatty animal products (except modest amounts of fish), and refined carbohydrates has been shown to reduce free radical formation, reverse or at least slow degenerative diseases, and may even slow the aging process.By James J. Kenney, PhD, RD, FACN1 JAMA 2007;297:842-57