Level 1: Likely reliable evidence
Previous research has suggested an association between selenium and vitamin E and reduced prostate cancer risk. The recently published Selenium and Vitamin E Cancer Prevention Trial (SELECT) provides evidence contradicting this claim (JAMA. 2009;301:39-51, accessed March 11, 2009). Neither selenium (200 µg/day) nor vitamin E (400 units/day), alone or in combination, reduced the risk of prostate cancer or other cancers in men. This randomized trial included more than 35,000 men at least 55 years old (or at least 50 years old if African American) without prostate cancer and with serum prostate-specific antigen levels <4 ng/mL. Patients were randomized to selenium and/or vitamin E or placebo. Absence of benefit resulted in termination of the trial after seven years. There were no significant differences in prostate cancer, any other primary cancer, cardiovascular events, or mortality.