Vitamins in the normal diet are essential for good performance

Vitamins

Vitamins in the normal diet are essential for good performance in work and sport. Following the principle that if a little of something is good, then a large amount of the same thing should be better, the discovery and identification of vitamins led to the administration of large doses of these substances in the hope that such a superdiet would result in superperformance. Where vitamins were lacking in the diet these superdiets did improve performance but extra vitamins added to normal diets did not improve performance.

Healthy young men expending an average of 3700 to 4200 Calories per day are not benefitted by a daily dietary supply in excess of 1.7 mg. thiamin chloride, 2.4 mg. riboflavin and 70 mg. ascorbic acid. Fortification of normal diets with vitamins does not improve fitness for work and exercise. This has been shown in static and dynamic work tests, muscular endurance tests, work in heavy industry and treadmill running tests. In neither brief, exhausting exercise nor in prolonged, severe exercise are there any indications of benefit due to dietary supplements of thiamin chloride, cocarboxylase, riboflavin, nicotinic acid, pyridoxin, pantothenic acid, and ascorbic acid or to vitamin B complex given intravenously.

Vitamins are stored in varying amounts in the body. When diets are deficient in vitamins, the stores are depleted and the consequent deterioration in physical condition results in a reduction in the capacity for muscular work. The effects of deficiencies of the various vitamins are discussed separately because of the specific torture of the results in each case.