In 2001 the Selenium and Vitamin E Cancer Prevention Trial (SELECT) was initiated to determine if selenium or vitamin E would decrease the risk of prostate cancer.  In 2008, the study was stopped early (planned to cease in 2012) because the results demonstrated that there was no protective effect from selenium and suggested that vitamin E increased prostate cancer risk by 17%.

Vitamin E, found in vegetables, nuts, and eggs acts as an antioxidant.  Selenium does the same and is found in meat.  These are thought to prevent the effects of oxidation on fat cells, which are thought to increase mutations that can become malignant.

Currently, the evidence from the trial suggests the idea that the risk of prostate cancer may be increase by these supplements.  Currently, as published in the Journal of the National Cancer Institute, these supplements not only appear not provide protection, but may possibly increase the risks of prostate cancer.

In reality, patients looking to prevent prostate cancer should not start these medications, and then confer with their physicians prior to attempting any new dietary changes.

"Men using these supplements should stop, period. Neither selenium nor vitamin E supplementation confer any known [health] benefits — only risks," said lead author Alan Kristal, DrPH, from the Fred Hutchinson Cancer Research Center in Seattle, in a press statement.