07.01.09
Supplementation with antioxidant vitamins C and E may preclude the health-promoting effects of exercise, a study published in The Proceedings of the National Academy of Sciences has found. Researchers evaluated the effects of a combination of vitamin C (1000 mg/day) and vitamin E (400 IU/day) on insulin sensitivity in about 40 healthy young men, as measured by glucose infusion rates (GIR) over a period of four weeks. GIR was determined, and muscle biopsies for gene expression analyses as well as plasma samples were obtained to compare changes over baseline and potential influences of vitamins on exercise. The study said that while exercise-induced oxidative stress ameliorates insulin resistance and promotes endogenous antioxidant defense, supplementation with antioxidant vitamins might preclude these benefits.