- Vitamin E
- Alpha-tocopherol, an antioxidant vitamin which binds oxygen free radicals that can cause tissue damage. Deficiency of vitamin E can lead to anemia. Vitamin E may play a possible role in preventing heart disease and cancer of the lung and prostate. Vitamin E and the heart: In the Nurses’ Health Study involving 80,000 women, subjects who took more vitamin E had a lower rate of heart attacks than those who consumed less vitamin E. However, in the ATBC (Alpha-Tocopherol Beta-Carotene Cancer Prevention) trial, men with known coronary artery disease given 50 mg of a synthetic vitamin E had no reduction in fatal heart attacks as compared with men given a placebo. In the CHAOS (Cambridge Heart Antioxidant Study) trial, patients with known coronary artery disease were given natural vitamin E or a placebo. The dose of vitamin E used (400-800IU) in this trial was 13 to 26 times greater than the RDA, and much higher than the ATBC cancer prevention trial. The vitamin E treated group experienced fewer heart attacks than the placebo group after one year of treatment. Vitamin E and the prevention of lung cancer: Damage to DNA from free radicals can, it is thought, lead to the development of cancers. However, randomized, prospective, placebo-controlled trials involving antioxidant vitamins have generally yielded disappointing results. In the ATBC cancer prevention study, vitamin E was shown not to be beneficial in preventing lung cancers. Vitamin E and the prevention of prostate cancer: In the ATBC cancer prevention trial, men given alpha-tocopherol (vitamin E) had a lower incidence of prostate cancer than men given a placebo. The vitamin E-treated group also had significantly lower death rates from prostate cancer. Long-term vitamin E supplementation may thus reduce the incidence of prostate cancer and deaths from this cancer. Other controlled studies will be necessary to confirm these findings.
* * *vitamin E n any of several fat-soluble vitamins that are chemically tocopherols or tocotrienols, are essential in the nutrition of various vertebrates in which their absence is associated with infertility, degenerative changes in muscle, or vascular abnormalities, are found esp. in wheat germ, vegetable oils, egg yolk, and green leafy vegetables or are made synthetically, and are used chiefly in animal feeds and as antioxidants esp ALPHA-TOCOPHEROL
* * *any of a group of chemically related fat-soluble compounds (tocopherols and tocotrienols) that have antioxidant properties and are thought to stabilize cell membranes by preventing oxidation of their unsaturated fatty acid components. The most potent of these is a-tocopherol. Good sources of the vitamin are vegetable oils, eggs, butter, and wholemeal cereals. It is fairly widely distributed in the diet and a deficiency is therefore unlikely. There is evidence to suggest that vitamin E supplements (400-800 mg/day) reduce the risk of coronary thrombosis in patients with heart disease.
* * *1. any of a group of at least eight related compounds with similar biological antioxidant activity, particularly α-tocopherol but also including other isomers of tocopherol and the related compound tocotrienol. It occurs naturally in wheat germ oil, cereal germs, egg yolk, liver, green plants, milk fat, and vegetable oils and is also prepared synthetically. In various species, it is important for normal reproduction, muscle development, and resistance of erythrocytes to hemolysis, but deficiency in human children and adults is rare except in severe cases of malabsorption. Deficiency is rare and is seen more often in children than in adults, with symptoms such as hemolytic anemia and neurologic disorders including gait ataxia, weakness, incoordination, loss of tendon reflexes, ophthalmoplegia, and dysarthria. The term is sometimes used synonymously with α-tocopherol. 2. an official preparation comprising some combination of the d- or dl-isomers of α-tocopherol, α-tocopheryl acid succinate, and α-tocopheryl acetate; used as dietary supplement, administered orally.
Medical dictionary. 2011.
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