Is there a role for prescribing antioxidant vitamins to patients with coronary artery disease? If so, who should get them, and at what dose?

Three large prospective studies have shown that vitamin E users have a 40% lower rate of coronary artery disease. At least 100 IU/day of supplement is required to gain benefit. However, one large study in postmenopausal women showed no benefit from vitamin E supplementation, but high dietary vitamin E consumption reduced the risk by 58%.

At present there are only two intervention studies in patients with coronary artery disease available to guide therapeutic decisions. The CHAOS study1 used 400 or 800 IU/day while the ATBC study2 used 50 IU/day. Both studies showed that vitamin E does not save lives in patients with coronary artery disease and that it may increase the number of deaths. Both studies also agree that non-fatal myocardial infarctions are reduced significantly, by 38% in the ATBC study and by 77% in the CHAOS study, with a 53% reduction in combined events in the latter study. In the CHAOS study of 2002 patients, 27 heart attacks were prevented at the expense of 9 additional deaths (albeit statistically non-significant) while in the ATBC study the 15 fewer non-fatal heart attacks were balanced by 15 additional cardiovascular deaths. In the latter study it could be argued that the low dose of vitamin E used did not prevent myocardial infarction but when one occurred it was more often fatal. Until more compelling evidence is available the potential adverse effect of vitamin E does not outweigh the benefit of fewer non-fatal myocardial infarctions. Patients should be advised to eat diets rich in fruit and vegetables instead.