Vitamin E and Prostate Cancer—A Connection?

A recent study “to determine the long-term effect of vitamin E and selenium on the risk of prostate cancer in relatively healthy men” published in The Journal of the American Medical Association October 12, 2011, is casting some light on a possible connection between Vitamin E supplement consumption and prostate cancer. The study’s conclusion: “Dietary supplementation with vitamin E significantly increased the risk of prostate cancer among healthy men.”

Howard Parnes of the National Cancer Insitute (NCI), one of the National Institutes of Health (NIH) of the U.S. Department of Health and Human Services (DHHS), Washington, D.C., noted in an October 12 Washington Post article, that while the public generally perceives vitamins as safe, that is not necessarily the case. Certain vitamins in mega- or large doses have been shown to be toxic to the human body. Parnes noted, “scientists and the dietary supplement industry have criticized the study for attempting to evaluate individual vitamins,” but this study also included selenium. “Selenium is a trace element that is essential in small amounts, but like all essential elements, it is toxic at high levels.”

Acting Director of the National Cancer Institute’s Division of Cancer Prevention program and one of the study co-authors, Lori Minasian, noted that “this study used the alpha-tocopherol form of Vitamin E which some scientists suggest is less beneficial to the human body, rather than the gamma-tocopherol form of vitamin E.” At least one Canadian scientist’s initial impression is that the conclusion of increased risk of oncogenecity of Vitamin E might be a statistical fluke, but data from 35,533 men from 427 study sites in the United States, Canada, and Puerto Rico were used for this study. According to NCI’s associate director for clinical research Leslie Ford, it is “the largest, most definitive, and the first one to show that there could potentially be harm,’ from regular use of vitamin E.

Dr. Otis Brawley, chief medical officer for the American Cancer Society, who was not involved in this particular study, says men “should stop taking large doses [of Vitamin E] and talk to their doctors about risks and benefits from prostate cancer screening. Smaller doses, typically found in multivitamins, are probably fine.”