If you're a male taking vitamin E, consider tossing your supplements. According to a study published this week in the Journal of the American Medical Association, the antioxidant supplement increases the risk of prostate cancer.
The study - called SELECT (the Selenium and Vitamin E Cancer Prevention Trial) - found that men who took 400 IU (international units) of vitamin E each day were 17 percent more likely to develop prostate cancer than non vitamin E users.
Findings from earlier studies investigating supplements and risk for other types of cancer suggested that supplemental vitamin E and selenium guarded against prostate cancer. In 1998, a Finnish study of male smokers who took 50 IU of vitamin E in the hopes of preventing lung cancer surprisingly found 32 percent fewer prostate cancers among vitamin E users.
In 2001, SELECT set out to substantiate these observations. The trial assigned 35,533 healthy men, aged 50 and older, to one of four treatment groups: 400 IU of vitamin E, 200 micrograms of selenium, vitamin E and selenium together, or placebo.
An earlier analysis, published in 2008, found no benefit - vitamin E and selenium, taken alone or in combination, did not prevent prostate cancer. However two worrisome treads emerged: a small increase in the number of prostate cancers among vitamin E users and a small rise in type 2 diabetes among men taking selenium. Neither finding was statistically significant, meaning it could be a coincidence.
The trial was discontinued early and men were told to stop taking their supplements. Since 2008, SELECT investigators have continued to follow participants and gather additional data to determine any long term effects of supplements on prostate cancer risk.
This week's report noted the rate of prostate cancer was 17 percent greater in the vitamin E group, a finding that was statistically significant. There was no increased risk of prostate cancer when vitamin E and selenium were taken together, suggesting that selenium somehow dampens the harm caused by vitamin E.
The fact that the increased risk of prostate cancer in the vitamin E group was only evident after extended follow up suggests that the health effects from these supplements may continue even after they are discontinued.
The updated SELECT results found no link between selenium supplements and type 2 diabetes risk. The longer follow up did not demonstrate a benefit for vitamin E and selenium supplements on the risk of colorectal or lung cancer or cardiovascular events.
If you take vitamin E in the hopes or warding off chronic disease, it's time to trade in your supplement for a healthy diet. Clinical trials have not demonstrated a benefit for vitamin E supplementation on heart attack, death from heart disease, colorectal polyps, respiratory infections in elderly individuals or progression of cataract or macular degeneration.
The best sources of vitamin E include wheat germ oil, sunflower seeds, sunflower oil, safflower oil, grapeseed oil, almonds, hazelnuts, mixed nuts, frozen spinach, beet greens, canola oil and papaya.
Most multivitamins contain a small dose of vitamin E, 25 to 50 IU. But check your supplement to be sure. (SELECT gave men 400 IU of vitamin E daily.)
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.