Vitamin E-nough But Not Too Much

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An article in this week's Journal of the American Medical Association (JAMA) (1) adds to the mounting evidence (which ACSH has frequently pointed out) that antioxidant supplements are not the potent health-promoters that proponents claim. The study indicates they may even increase the risk of one of the very conditions that some claim they prevent.

In the randomized placebo-controlled study, patients over the age of fifty-five with diabetes or vascular disease were given moderately high daily doses of vitamin E (400 IU) over seven years. Those who took vitamin E had a significantly higher risk of heart failure than those taking the placebo; there was also no evidence that they had lower rates of cancer than the control group.

An accompanying editorial in JAMA crisply sums up the existing research on vitamin E and discusses its implications for individuals' attempts to prevent heart disease and cancer. The authors state that doctors can now answer patients' inquiries about vitamin E by saying:

In nearly 68,000 patients studied to date, there is no compelling evidence that higher doses of vitamin E reduce cardiovascular risk or cancer; there are even some hints that vitamin E, in excess of normal daily intake, may slightly increase the risk of ischemic events or of heart failure. You may hear that vitamin E is a "natural," yet effective, way to prevent heart disease or cancer, but this has proven to be a false hope. You should not be misled into neglecting other proven methods of prevention. (2)

We could hardly have put it better ourselves. Furthermore, when these results are viewed along with the results of many studies of other antioxidant supplements (such as vitamin C and beta-carotene) indicating that they do not have benefits and in fact my cause harm, it begins to look as if antioxidant supplements as a whole ought not to be recommended. Instead, focusing on reducing one's risk of heart disease and cancer through proven methods, such as avoiding smoking, eating a balanced and varied diet that is high in fruits and vegetables, and exercising, is most prudent.

(1) HOPE and HOPE-TOO Trial Investigators. (2005). Effects of the long-term use of vitamin E supplementation on cardiovascular events and cancer: A randomized controlled trial. JAMA, 293, 1338-1347.
(2) Brown, BG & Crowley, J. (2005). Is there any hope for vitamin E? JAMA, 293, 1387-1390.

Rivka Weiser is a research intern at the American Council on Science and Health.