Prostate Cancer Risk May Be Increased by Vitamin E Supplements: Study

Vitamin E supplements may be linked to an increase in the risk of prostate cancer among men, U.S. researchers say. 

According to the findings of a study published in the Journal of the American Medical Association, men who took vitamin E on a daily basis had a 17% increased risk of developing prostate cancer.

Researchers examined data from the Selenium and Vitamin E Cancer Prevention Trial (SELECT), which looked at more than 35,000 men age 50 or older at more than 400 study sites nationwide. The study began in 2001 with a goal of finding out whether vitamin E or selenium dietary supplements, or a combination of the two, could be used to reduce the risk of prostate cancer.

Initial results indicated that short-term use of vitamin E supplements resulted in a small increase in prostate cancer risk, but that was not statistically significant. The study was ended in 2008 after it became clear that neither vitamin E or selenium helped prevent prostate cancer.

In this latest study, researchers looked at the long-term effects of selenium and vitamin E on the test subjects, finding that 620 men in the group given vitamin E supplements had developed prostate cancer, compared to 529 men in the control group, 57 in the selenium group and 555 in the combined selenium and vitamin E group.

Researchers were at a loss to explain why vitamin E supplements increased prostate cancer risk and noted that there was no increase among men given selenium and vitamin E, which could mean selenium has some prophylactic effect.

“Despite the lack of a mechanistic explanation, the findings show that vitamin E supplementation in the general population of healthy men significantly increases the risk of being diagnosed with prostate cancer,” the researchers concluded. “The lack of benefit from dietary supplementation with vitamin E or other agents with respect to preventing common health conditions and cancers or improving overall survival, and their potential harm, underscore the need for consumers to be skeptical of health claims for unregulated over-the-counter products in the absence of strong evidence of benefit demonstrated in clinical trials.”

The findings come about a year after several states reached a $3.3 million settlement with Bayer after suing the drug maker for false marketing claims that it’s One-A-Day multivitamins helped prevent prostate cancer. The company claimed that “emerging science” showed that selenium prevented prostate cancer despite study findings to the contrary.