Antioxidants prevent health-promoting effects of physical exercise in humans

Researchers gave healthy young men either vitamin C and vitamin E pills or look-alike placebo pills while they followed an exercise program for four weeks. The vitamin group took 1,000 milligrams of vitamin C and 400 international units of vitamin E each day. The researchers measured insulin sensitivity, meaning how well the body responds to insulin, and the body’s own antioxidant defenses. Exercise improved these measures in the placebo group, but the improvements were largely absent in the men taking antioxidants.

What this means for you: This small, short study does not support taking high-dose antioxidant pills to improve exercise results. Regular exercise is still worthwhile, but the findings suggest that large doses of vitamins C and E may interfere with some training benefits.