In a counter-intuitive article in the New York Times, which quotes researchers in Germany and Boston, exercise and antioxidants don’t mix. “If you exercise to improve your metabolism and prevent diabetes, you may want to avoid antioxidants like vitamins C and E.”

Dr. Michael Ristow, a nutritionist at the University of Jena in Germany, said, “If you exercise to promote health, you shouldn’t take large amounts of antioxidants. … antioxidants in general cause certain effects that inhibit otherwise positive effects of exercise, dieting and other interventions.”

It seems that exercise encourages muscle cells to metabolize glucose by combining carbon atoms with oxygen. In the process, highly reactive oxygen molecules are released which then attack various parts of the body damaging the tissues.

The Jena team found that in the group taking antioxidant vitamins, like vitamins C and E, there was no improvement in insulin sensitivity and almost no activation of the body’s natural defence mechanism against oxidative damage.

Once again, what we thought was done and dusted has been called into question by more research.

However, the advice does not apply to fruits and vegetables, Ristow said, even though they are high in antioxidants, it may be that other substances they contain outweigh any negative effect.

Andrew Shao of the Council for Responsible Nutrition, a trade association of dietary supplement makers, said, “I wouldn’t change recommendations for anyone based on one study. This is one small piece of the puzzle.”

The amount of oxidative damage increases with age, and according to one theory of aging it is a major cause of the body’s decline.

The findings appear in this week’s issue of The Proceedings of the National Academy of Sciences.

John Evans