01-13-2010, 05:09 PM
A group of related compounds called tocopherols which maintain the integrity of cell membranes. Vitamin E is an antioxidant and mutually protects vitamins A and C. Some coaches claim that it increases muscular development and function; this claim is hotly disputed, but there is considerable support for the suggestion that vitamin E reduces the oxygen requirements of muscles and so enhances performance. It has been suggested that physical endurance at high altitudes may be increased, and oxygen debt reduced, by taking 1200 IU of vitamin E per day. Such high doses can be toxic and should be taken only under medical supervision. Vitamin E is widely available in the diet. The richest sources include wheatgerm oil, sunflower oil, and roasted peanuts. Natural sources of Vitamin E are almost twice as potent as synthetic vitamin E. Natural and synthetic forms can be identified by subtle differences in the names of their main components: natural forms are known as ‘d-alpha tocopherol’ and the synthetic ones as ‘dl-alpha tocopherol’. Vitamin E deficiencies are rare, but when they do occur they may lead to destruction of red blood cells and anaemia. Deficiencies impair the reproductive ability of rats and causes muscle wasting in pigs, but vitamin E has no effect on human fertility or libido. There is a growing body of good evidence that vitamin E supplements may offer some protection against atherosclerosis and heart disease. It has also been suggested that supplements may reduce the risk of miscarriages, but this suggestion is disputed.