vitamin supplementation

Additional vitamins taken to make up a deficit, to avoid a vitamin deficiency disease, or to enhance athletic performance. There is much controversy concerning the value of vitamin supplements as ergogenic aids. There is little evidence to support the notion that extra vitamins improve the physical performance of athletes already eating a balanced diet and not suffering from a vitamin deficiency. However, high doses of vitamins may improve athletic performance by acting as drugs in, as yet, undefined ways.

There is general agreement that physical activity increases vitamin requirement, but many sports nutritionists believe that the increased requirement can be satisfied by a balanced diet. As exercise increases, food intake will increase and so should vitamin intake if the right foods are eaten. Nevertheless, because the difference between success and failure in sport may be very finely balanced, many coaches like to ensure that their athletes are taking sufficient vitamins, particularly the energy-related B vitamins, and advocate moderate multi-vitamin supplementation. Those taking supplements should be aware of the risk of toxicity from overdoses. This especially applies to the vitamins A, B₆, D, and niacin. Vitamin B complex tablets, particularly those containing nicotinic acid, should not be taken immediately before a prolonged bout of exercise because nicotinic acid can impair endurance by preventing mobilization of free fatty acids used as an energy source.

Additional vitamins taken to make up a deficit, to avoid a vitamin deficiency disease, or to enhance athletic performance. There is much controversy concerning the value of vitamin supplements as ergogenic aids. There is little evidence to support the notion that extra vitamins improve the physical performance of athletes already eating a balanced diet and not suffering from a vitamin deficiency. However, high doses of vitamins may improve athletic performance by acting as drugs in, as yet, undefined ways. Also, athletes in hard training are generally advised to take care that they have a sufficient intake of antioxidant vitamins to counteract the harmful effects of free radicals produced as a result of the high energy turnover of active skeletal muscle (this can be up to 100 times the resting rate). Taking supplements of fat-soluble vitamins can be dangerous because they can be stored in adipose tissue and may be toxic in high concentrations. See also sports nutrition.