A new study says that higher intake of selenium may reduce colorectal cancer risk. In the past, selenium has been associated with cancer protection, particularly prostate, lung and colon cancers.

To gain better insight into selenium’s anti-cancer role, researchers from the University of Arizona analyzed data from three completed clinical trials, each with several hundred participants. After adjustment for age, gender, smoking status and study site, each of the trials showed lower risk of colorectal cancer in participants with the highest intake of selenium. The researchers named several possible mechanisms for this benefit, including protection against DNA damage and increased immune system activity.

In a second study at the Arizona Cancer Center, researchers found a significant link between selenium supplementation and lower prostate cancer incidence in a trial involving 1,312 participants. In this randomized trial, participants received a placebo or 200 mcg daily of selenium. They found selenium supplementation to significantly reduce the overall incidence of prostate cancer. Participants with lowest blood selenium levels had the most significant reductions in prostate cancer incidence, leading researchers to conclude that the trial “continued to show a significant protective effect of selenium supplementation on the overall incidence of prostate cancer.”

Sources: J Nat Canc Inst 96:1645-1647; BJU Int. 2003 May;91(7):608-12