The role of vitamin C in athletic performance.

Abstract

There is widespread belief among athletes that special nutritional practices--in particular high-protein diets--will enhance their achievements in competition. Supplementation with vitamins, especially vitamin C, is equally popular. But because genetic predisposition, hard physical training and psychological factors play a most important role in determining performance, and because any potential difference in achievement will be small, it is almost impossible to obtain scientific evidence of a beneficial effect of a particular nutrient. There have been many investigations during the past four decades of the potential effect of high-dose vitamin C supplementation on physical performance. The variables used have included maximum oxygen uptake, blood lactic acid levels, and heart rate after exercise, and in some cases performance was assessed in competitive events. The results have been equivocal: Most studies could not demonstrate an effect. On the other hand, a suboptimal vitamin C status results in an impaired working capacity which can be normalized by restoring vitamin C body pools. Athletes, who follow irrational, unhealthy eating patterns often not including vitamin-C-containing fruit and vegetables, are in need of nutrition education.

Vitamin-mineral supplement use and nutritional status of athletes.

“…Ascorbic acid concentrations of SU were significantly higher than NU and turnover may be greater during ex ercise than at rest [38]. Thus, increased vitamin C turnover among athletes may account for the lower levels among male NU than SU despite adequate intakes in both groups.…”

Extreme exercise and oxidative DNA modification

“…The notion is supported by the lowered levels of vitamin E in muscle seen after endurance training (Quintanilha, 1988). The role of antioxidant vitamins in the prevention of exercise-induced stress is still questioned (Gerster, 1989;Goldfarb, 1993). An acute bout of exercise does not affect hepatic or heart antioxidant enzyme activity, but some effects are seen in skeletal muscle, where glutathione peroxidase in particular shows an adaptive response (Ii, 1993).…”

Nutrition Antioxidant Status and Oxidative Stress in Professional Basketball Players: Effects of a Three Compound Antioxidative Supplement

“…The specific physical performance of professional basketball players characterised by high intensity exercise interrupted by short periods of reduced exercise intensity or rest, a long competition season, and the lack of adequate recovery periods might be responsible for these findings. As a marginal vitamin C status has been associated with impaired working capacity [11,34], increased severity of respiratory tract [13,33] and higher susceptibility to oxidative DNA damage [26], administration of an antioxidant supplement including vitamin C seems to be favourable for these athletes.…”