Selenium is touted for preventing and fighting colorectal cancer. But a 12-year study conducted by researchers with the University of Arizona (UA) Cancer Center found that the nutritional supplements can significantly increase the risk for type 2 diabetes.
Selenium has been a popular dietary supplement for decades. It is thought to have antioxidant properties and to play a role in stopping free radicals from damaging cells and DNA. For this reason, it was thought to offer protection against cancer.
But a new study questions whether the risks associated with selenium outweigh the perceived benefits. A randomized clinical trial involving 1,824 participants from Arizona, Colorado, Texas and New York found that selenium did not prevent the development of colon polyps, often a precursor to colon cancer. Researchers also noted that older participants who took selenium were at greater risk of developing type 2 diabetes.
“The possibility that selenium supplements may increase the risk of type 2 diabetes has been hinted at before,” said Dr. Peter Lance, deputy director of the UA Cancer Center and the study’s principal investigator. “But this is the first study to have substantiated such a risk in the setting of a prospective, randomized, placebo-controlled trial.”
Study participants were randomly assigned to take 200 mcg of selenium or a placebo daily. Another group was treated with celecoxib, a selective COX-2 inhibitor non-steroidal anti-inflammatory drug (NSAID) or placebo daily. Researchers found that while a 400 mg dose of the NSAID prevented colon polyps in high-risk patients, it also put participants with pre-existing cardiovascular risk factors at greater risk of hypertension.
Researchers said the study helped refine the understanding of the effects of selenium for colon cancer prevention.
Source: UA News