Abstract

Does Vitamin E Prevent or Promote Cancer?

Abstract

The cancer preventive activity of vitamin E has been suggested by many epidemiologic studies. However, several recent large-scale human trials with a (alpha) tocopherol, the most commonly recognized and used form of vitamin E, failed to show a cancer preventive effect. The recently finished follow-up of the Selenium and Vitamin E Cancer Prevention Trial (SELECT) even showed higher prostate cancer incidence in subjects who took a-tocopherol supplementation. The scientific community and the general public are faced with a question: “Does vitamin E prevent or promote cancer?” Our recent results in animal models have shown the cancer preventive activity of y (gamma) and (other) tocopherols as well as a naturally occurring mixture of tocopherols, and the lack of cancer preventive activity by a (alpha) tocopherol. On the basis of these results as well as information from the literature, we suggest that vitamin E, as ingested in the diet or in supplements that are rich in y (gamma) and (other) tocopherols, is cancer preventive; whereas supplementation with high doses of a (alpha) tocopherol is not.