Vitamin E supplement may increase prostate cancer risk, US study
Men who take a daily vitamin E supplement – a regimen once thought to reduce cancer risk – face an increased risk of prostate cancer, according to findings published in the Journal of the American Medical Association today.
Foods said to be rich in vitamin E include wheat germ oil, sunflower oil, nuts and nut oils, green leafy vegetables like lettuce, spinach, turnip, tomato products, mangoes, broccoli, and avocadoes.
The findings refer to the latest results of the Selenium and Vitamin E Cancer Prevention Trial (known as SELECT). Eric Klein, Chair of the Glickman Urological and Kidney Institute at Cleveland Clinic, is the lead author of the study report.
SELECT began in 2001 to test earlier research suggesting selenium and vitamin E supplements may reduce the risk of developing certain cancers. Some vitamin supplements containing enhanced levels of selenium and vitamin E were marketed to consumers during this time period with claims of reducing cancer risk.
Dr Klein and colleagues said they found that a group of men taking a daily dose of vitamin E from 2001 to 2008 had 17 per cent more cases of prostate cancer than men who took a placebo.
“For the typical man, there appears to be no benefit in taking vitamin E, and in fact, there may be some harm,” said Dr. Klein. He said that SELECT tracked more than 35,000 men at locations across the United States, Canada, and Puerto Rico who took daily doses through the autumn of 2008. The trial was funded by the National Cancer Institute and administered by the Southwest Oncology Group (SWOG), an international network of research institutions with study sites in 400 locations across the U.S., Puerto Rico and Canada.
The men were divided into four groups: vitamin E and Selenium; vitamin E alone; selenium alone; and placebo. The group taking vitamin E was the only group shown to have a statistically significant increased risk of prostate cancer.
Dr Klein said that prostate cancer is the most common non-skin cancer in American men with a current lifetime risk of 16 percent. He added, “For 2011, 240,000 new cases have been estimated, resulting in an estimated 33,000 deaths in the U.S.”
The SELECT study used the synthetic form of Vitamin E (dl racemic tocopherol acetate), not the natural form (d alpha tocopherol) found to have positive effect on reducing prostate cancer occurence and the most commonly available form in Australia. dl alpha racemic tocopherol is made by combining 2 environmentally hazourdous substances – racemic isophytol and trimethylhydroquinone. A positive effect for reducing prostate cancer incidence was previously reported for dl tocopherol acetate albeit at lower dosage level 50IU (ATBC trial).
http://jama.ama-assn.org/content/301/1/39.short
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People need to know that the increase in the group given vitamin E was not statistically significant.