Effects of an antioxidant vitamin mixture on lipid peroxidation at rest and postexercise

We studied the effects of ingesting an antioxidant vitamin mixture for 6 wk on breath pentane and serum malondialdehyde (MDA) levels before and after exercise. Twenty young (mean age 25.0 +/- 2.9 yr) healthy males were randomly assigned to either an antioxidant vitamin group (daily doses of 592 mg of alpha-tocopherol equivalents, 1,000 mg of ascorbic acid, and 30 mg of beta-carotene) or a placebo group. Exercise consisted of 30 min of treadmill running at 60% of maximal O2 consumption (VO2max) followed by 5 min of running at a pace that elicited approximately 90% of VO2max. Blood and breath samples were collected immediately after the two exercise bouts. The antioxidant supplement did not prevent the exercise-induced increase in lipid peroxidation, as reflected by the rate of pentane production and the increase in serum MDA concentration. However, ingestion of the antioxidant vitamins did result in significantly lower resting and postexercise levels of expired pentane and serum MDA. We conclude that taking ascorbate, alpha-tocopherol, and beta-carotene in the amounts used in this study serves to lower markers of lipid peroxidation at rest and after exercise but does not prevent the exercise-induced increase in oxidative stress.