Antioxidants fail to prevent prostate cancer
Selenium, vitamins C, E don’t lower incidence of prostate cancer in two large trials
By Nathan Seppa
Despite much hope generated by earlier studies, vitamins C and E and the element selenium have failed to reduce the incidence of prostate cancer. The disappointing news from two huge trials is reported online December 9 in the Journal of the American Medical Association.
In one trial, more than 14,000 male physicians age 50 or older were randomly assigned to take vitamin E, vitamin C, both or placebos starting in the 1990s. Researchers monitored the men’s health over eight years on average.
Nearly 2,000 cases of cancer arose in the men during the trial, roughly half of which were prostate cancer. But taking a vitamin didn’t affect a man’s likelihood of developing prostate cancer or any other malignancy, the data show.
In the other trial, started in 2001, more than 35,000 men also age 50 or older were randomly assigned to get vitamin E, selenium or a placebo. After more than five years of follow-up per participant, on average, more than 1,700 cases of prostate cancer occurred. A panel monitoring the ongoing results stopped the trial after determining that the supplements had no effect on prostate cancer risk.