Nutraceutical: Vitamin E

Indication: Prostate cancer

Source: JAMA, October 12, 2011;306(14): 1549-56.

Research: The initial report of the Selenium and Vitamin E Cancer Prevention Trial (SELECT) found no reduction in risk of prostate cancer with either selenium or vitamin E supplements but a statistically non-significant increase in prostate cancer risk with vitamin E. But researchers contend that longer follow-up and more prostate cancer events have provided further insight into the relationship of vitamin E and prostate cancer. As part of their analysis, researchers set out to determine the long-term effect of vitamin E and selenium on risk of prostate cancer in relatively healthy men. A total of 35,533 men from 427 study sites in the U.S., Canada and Puerto Rico were randomized between August 22, 2001 and June 24, 2004. Eligibility criteria included a prostate-specific antigen (PSA) of 4 ng/mL or less, a digital rectal examination not suspicious for prostate cancer, and age 50 years or older for black men and 55 years or older for all others. The primary analysis included 34,887 men who were randomly assigned to one of four treatment groups: 8752 received selenium; 8737, vitamin E; 8702, both agents; and 8696, placebo. Researchers’ analysis reflects the final data collected by the study sites on their participants through July 5, 2011.

Results: This report includes 54,464 additional person-years of follow-up and 521 additional cases of prostate cancer since the primary report. Compared with the placebo (referent group) in which 529 men developed prostate cancer, 620 men in the vitamin E group developed prostate cancer, as did 575 in the selenium group, and 555 in the selenium plus vitamin E group. Compared with placebo, the absolute increase in prostate cancer risk per 1000 person-years was 1.6 for vitamin E, 0.8 for selenium and 0.4 for the combination. As a result, researchers believe dietary supplementation with vitamin E significantly increases the risk of prostate cancer among healthy men.