Can selenium and vitamin E supplementation prevent prostate cancer?

Can’t.

A large randomized, placebo-controlled trial, the Selenium and Vitamin E Cancer Prevention Trial (SELECT [NCT00006392]), provided credible evidence for the cancer-preventive effects of vitamin E and selenium.

In this study:

529 men in the placebo group developed prostate cancer, compared with 620 in the vitamin E group, significantly more than in the placebo group;

There were 555 prostate cancers in the selenium + vitamin E group and 575 in the selenium alone group, both of which were not significantly different from the placebo group.

The results of the study showed that:

Supplementation with vitamin E and selenium did not reduce the prevalence of prostate cancer, and vitamin E alone increased the risk of prostate cancer.

Notably, the elevated risk of prostate cancer from vitamin E was found after discontinuation of the supplement, suggesting that vitamin E may have a long-term effect.