Vitamin E and Prostate Cancer: Trial Results

Each year, around 240,000 American men will be diagnosed with prostate cancer and about 33,000 will die from it. Thousands who survive prostate cancer end up incontinent, impotent or both as a result of medical treatment. Over the past decade, epidemiological studies, animal studies, and other preclinical data have suggested that higher levels of antioxidants such as vitamin E and selenium may reduce the risk of developing prostate cancer. News reports and questionable claims made from overly zealous health pro- fessionals and sales pitches from the health food industry have led millions of men to take supplements of vitamin E and/or selenium in hopes of cutting their risk of developing prostate cancer.In order to evaluate the effectiveness of these supplements, a group of over 35,000 North American men were randomly assigned to receive a supple- ment of 400IU of vitamin E and/or a supplement of 200mcg of selenium or look alike placebos. After 7-12 years of follow-up, a total of 529 men in the double placebo group were diagnosed with prostate cancer. In those taking the Vitamin E supplement, a total of 620 men were diagnosed with prostate cancer. This 17% increased risk in those taking vitamin E was statistically significant. There was also more prostate cancer diagnosed in those receiving the selenium and selenium + vitamin E groups but these 9% and 5% increases did not reach statistical significance.1 Clearly, men taking supplements of these antioxidants in hopes of preventing prostate cancer ought to be informed that likely won’t work and may very well modestly increase their risk of developing prostate cancer.Researchers at the UCLA Jonsson Comprehensive Cancer Center published results of a clinical trial in which men with prostate cancer were fed a low-fat (15% calories) diet supplemented with fish oils (5g/d) or a typical high-fat Western diet for 4 to 6 weeks before having their prostates removed. Dr. Aronson’s study showed that the low-fat diet + fish oil markedly reduced the number of rapidly dividing prostate cancer cells compared to the high-fat diet. The results of this study were published in the October 25, 2011 issue of Cancer Prevention Research. The results of this study add to the growing body of evidence linking the typical high-fat Western diet may be promoting the growth and suggesting a low-fat diet with omega-3 rich seafood replacing fatty meats and dairy products may very well reduce the risk of prostate cancer developing and spreading.Bottom Line: As we have seen many times, once large well-controlled clinical trials are conducted to establish the safety and efficacy of various nutrients or nutrient combinations for the prevention or treatment of common diseases, the results are more often than not disappointing. Food over supplements seems the way to go.By James J. Kenney, PhD, FACN1. JAMA 2011;306:1549-56