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.