Selenium has previously been associated with cancer protection, with several studies showing that it may help combat prostate cancer. However past research on selenium and colorectal cancer has yielded mixed results.
Researchers from the University of Arizona say however that these studies may have been too small to track the mineral's impact.
To gain better insight into the selenium's anti-cancer role, they pooled data from three completed clinical trials of colorectal adenoma: the Wheat Bran Fiber Trial, the Polyp Prevention Trial, and the Polyp Prevention Study, each with several hundred participants.
After adjustment for age, gender, smoking status and study site, each of the trials showed lower risk of adenoma recurrence in patients with the highest quartile of blood selenium level versus those in the lowest quartile, although only the Polyp Prevention Study was statistically significant.
Writing in the 17 November issue of the Journal of the National Cancer Institute (96:1645-1647), the authors explain that there are several possible mechanisms for this effect, including protection against DNA damage, induction of apoptosis, and increased immune system activity.
The Selenium and Vitamin E Cancer Prevention Trial (SELECT), looking at the impact of these nutrients on prostate cancer, may provide some new insight into the mechanisms of the mineral's anti-cancer activity.
