Definition of Vitamin E
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.
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.
However, newer studies from a trial called SELECT showed that taking vitamin E can actually be harmful. According to an article in JAMA October 12, 2011, updated research finds that men who took vitamin E were at a higher risk of developing prostate cancer by about 17 percent.Source: MedTerms™ Medical Dictionary
Last Editorial Review: 9/20/2012
Medical Dictionary Definitions A - Z
Search Medical Dictionary