Selenium, Vitamin E Supplements Linked to Prostate Cancer Risk: Study

Researchers indicate that taking certain supplements may raise the risk of developing prostate cancer among men, including vitamin E and selenium. 

According to the findings of a study published last week in the Journal of the National Cancer Institute, vitamin E and selenium not only offer no additional prevention for prostate cancer; but may increase the risk of developing prostate cancer in the future.

Researchers studied more than 35,000 American men aged 55 years and older during the Selenium and Vitamin E Cancer Prevention Trial (SELECT). The SELECT study is an ongoing trial to designed to examine the effects of vitamins on prostate cancer.

Participants were provided 200 micrograms per day of selenium or 400 IU per day all-racemic alpha-tocopheryl acetate (AT), also known as vitamin E.

After receiving initial results from the study in 2008, researchers instructed participants to stop taking both supplements. They found high-doses of vitamin E increased the risk of prostate cancer by 17 percent.

Although the study was stopped early, participants were instructed to continue checking in with researchers. During the most recent check-in, nearly five years after the close of the study, researchers found selenium doubled the risk of high-grade prostate cancer and vitamin E more than doubled the risk of developing prostate cancer.

The findings come nearly a year after a $3.3 million settlement with Bayer was reached, after the drug giant was charged with making false claims that it’s One-A-Day multivitamins helped prevent prostate cancer.

Prostate cancer is the second most common cancer in men worldwide, afflicting more than 2.6 million American men. Experts estimate more than 230,000 new cases of prostate cancer will be diagnosed this year. Nearly 30,000 men will die from prostate cancer.

Vitamin supplements are often touted for offering additional doses of added dietary benefits. Vitamin E and selenium were thought to help prevent prostate cancer. Now, researchers warn the micronutrients may be toxic and offer no added benefits when taken in high amounts.

Doses taken during the study far exceed the dosage amounts found in most multivitamins, offering some relief to consumers. However, researchers warn, taking additional supplements still may not be warranted.

Prior studies have revealed similar findings concerning other vitamin supplements.

Earlier this month, Swedish researchers found men who took ascorbic acid supplements (vitamin C) more than seven times per week had an increased risk of developing kidney stones.