The role of vitamin E in the prevention of heart disease

Data from the 1970s first suggested that vitamin E may be effective in decreasing mortality from cardiovascular disease. As the understanding of the antioxidant effect of this vitamin evolved, researchers began to further study the biologic effects of vitamin E. In vitro studies have shown vitamin E to have several potentially cardioprotective effects, including antagonizing the oxidation of low-density lipoproteins, inhibiting platelet aggregation and adhesion, preventing smooth muscle proliferation, and preserving normal coronary dilation. Several prospective studies, including the US Nurses' Health Study and the US Health Professionals' Follow-up Study, found a 34% and 39% reduction, respectively, in the risk of having a cardiac event for those taking vitamin E supplements, The Iowa Women's Health Study found a 47% reduction in cardiac mortality. Results of randomized, controlled clinical trials have not found consistent benefit, however. The best known of these trials, the Cambridge Heart Antioxidant Study, found a 47% reduction in fatal and nonfatal myocardial infarction in patients with proven coronary atherosclerosis who were given 400 or 800 IU of vitamin E daily. There was, however, no effect on mortality. While emerging and promising data suggest the potential benefit of vitamin E for high-risk cardiac patients, physicians should be alert to the results of randomized, controlled clinical trials already in progress.