Antioxidant vitamin status in high exposure to oxidative stress in competitive athletes

Abstract

We conducted a cross-sectional study in 118 well-trained athletes to investigate 'high exposure' to sub-deficient antioxidant status, and consequently to oxidative damage, in relation to estimated daily energy expenditure (EE) and dietary antioxidant intake. Subjects completed 7 d food and activity records. Blood samples were obtained on day 8. Of the athletes 81, 60 and 43 % had intakes of vitamins E, C and β-carotene below two-thirds of the French RDA respectively, which is adjusted for EE (FRDAa). The deficit in vitamin E intake was positively correlated with EE (r0·51,P>0·0001). All the athletes had normal plasma vitamins E and C and 14 % had marginal plasma β-carotene. Plasma thiobarbituric acid-reactive substances (TBARS) did not increase with increased EE. As evidenced by ANOVA, EE-induced vitamin C intakes increased and consequently led to increased plasma ascorbic acid concentrations. In male athletes, plasma total carotenoids were negatively correlated with plasma TBARS concentrations (r–0·31,P>0·006). The relationship between vitamin C intakes and plasma concentrations was logarithmic (r0·59,P> 0·0001). To summarize, it is not clear whether vitamin E requirements are overestimated with reference to EE in the FRDAa. Daily requirements for vitamin C do not exceed 200 mg. Our present results could be interpreted as meaning that carotenoids play a protective role as exogenous antioxidants. Carotenoid intakes in athletes must be considered carefully.