Past experimental and epidemiological studies have suggested that vitamin E supplementation may prevent cancer and cardiovascular disease. However, most of these studies have focused on the short-term effects of taking vitamin E. Now, the results of a randomized, double-blind, placebo-controlled study have provided a sense of the long-term outcomes of supplementation.
Reporting in the March 16 issue of The Journal of the American Medical Association (2005; 239 , 1338–47), scientists described the effects of a daily dose of 400 International Units of vitamin E or a placebo. The participants, who were studied over an average of 7 years, included men and women over age 55 who had either vascular disease or diabetes mellitus.
Not only didn’t members of the vitamin E group fare better than those who received the placebo, but they were actually at greater risk in some cases. “In patients with vascular disease or diabetes mellitus, long-term vitamin E supplementation does not prevent cancer or major cardiovascular events and may increase the risk for heart failure,” the researchers concluded.