Antioxidants may aid colon health

Antioxidant supplements may prevent the development of new colon polyps in people with a history of colorectal tumors, says a new study.

In the randomized controlled trial, 411 participants received either placebo or an antioxidant supplement providing daily doses of 200 micrograms of selenomethionnine, 30 milligrams of zinc, 6,000 IU of vitamin A, 180 milligrams of vitamin C, and 30 milligrams of vitamin E (1). All the participants had already undergone surgery to remove one or more benign colorectal tumors (adenomatous polyps) that, in time, could progress to cancer. At the end of the study people in the antioxidant group experienced a 40 percent reduction in the incidence of new polyps of the large bowel. The benefit observed after the conclusion of the trial persisted through 13 years of follow up.

The study represents another step on the ladder of supporting the potential anti-cancer effects of antioxidant supplements and selenium. While the science may be lacking for colon health, a greater body of science exists for prostate health. A number of studies have reported that the nutrients, alone or in combination, may reduce the risk of prostate cancer.

Despite great promise over vitamin E and selenium, recent results from the Selenium and Vitamin E Cancer Prevention Trial (SELECT) reported no significant differences between any of the groups in relation to prostate cancer risk (2). However, experts criticized that given positive results from previous clinical trials and epidemiological studies, the design of SELECT, including the supplements used, may have undermined the results.

1. Bonelli L. Presentation at the Frontiers in Cancer Prevention Research Conference, American Association for Cancer Research, Houston. 2009.
2. Lippman SM et al. Effect of Selenium and Vitamin E on Risk of Prostate Cancer and Other Cancers. JAMA. 2009; 301(1):39–51.