The effect of diet on vitamin E intake and oxidative stress in response to acute exercise in female athletes.

Vitamin E is the major lipid-soluble antioxidant found in foods, and its bioavailability is affected by the presence of dietary fats. Athletes often consume lowfat diets and may be more susceptible to the oxidative stress produced by exercise due to the low availability of vitamin E. In this study, the effects of a low-fat diet on vitamin E intake and oxidative stress markers were assessed in collegiate female rowers. All subjects habitually consumed either a low-fat (LF; <40 g fat x day(-1)) or a high-fat (HF; >60 g fat x day(-1) diet. Subjects ran downhill for 45 min at 75% of their age-predicted maximal heart rate. Blood samples were collected immediately pre- and post-exercise, and at 6, 24, and 48 h post-exercise. Subjects in the LF group consumed significantly less vitamin E (2.9 mg vitamin E x day(-1)) than advised by the Recommended Dietary Allowance (RDA; 8.0 mg vitamin E x day(-1)) and than those in the HF group (9.8 mg vitamin E x day(-1); P<0.05). Plasma concentrations of vitamin E, malondialdehyde, and conjugated dienes were not significantly different between LF and HF before or after exercise. Creatine kinase became significantly elevated above baseline at 6 h and 24 h post-exercise in both groups (P<0.05). We can conclude from these data that although the subjects in the LF group were not consuming the recommended amount of vitamin E in their diets, their vitamin E intake appears to be sufficient to protect against the oxidative stress produced by this moderate-intensity exercise.