One of the most effective naturally occurring weapons against cancer is, like most healthy things, something many of us are not getting enough of. The mineral selenium has been shown in multiple studies to be an effective tool in warding off various types of cancer, including breast, esophageal, stomach, prostate, liver and bladder cancers. Not many people get the recommended dose of 200 micrograms a day. Most Americans only get between 60 and 100 micrograms of selenium daily from dietary sources, according to the Life Extension Foundation's Disease Prevention and Treatment. That means daily supplements might be worth considering.

Selenium was first used in conventional medicine as a treatment for dandruff, but our understanding of the mineral has come a long way since then. Today, research shows selenium, especially when used in conjunction with vitamin C, vitamin E and beta-carotene, works to block chemical reactions that create free radicals in the body (which can damage DNA and cause degenerative change in cells, leading to cancer).

Selenium also helps stop damaged DNA molecules from reproducing. In other words, selenium acts to prevent tumors from developing. "It contributes towards the death of cancerous and pre-cancer cells. Their death appears to occur before they replicate, thus helping stop cancer before it gets started," says Dr. James Howenstine in A Physician's Guide to Natural Health Products That Work.

Selenium makes chemotherapy safer, more effective
In addition to preventing the onset of the disease, selenium has also been shown to aid in slowing cancer's progression in patients that already have it. According to the Life Extension Foundation, the use of selenium during chemotherapy in combination with vitamin A and vitamin E can reduce the toxicity of chemotherapy drugs. The mineral also helps "enhance the effectiveness of chemo, radiation, and hyperthermia while minimizing damage to the patient's normal cells; thus making therapy more of a 'selective toxin,'" says Patrick Quillin in Beating Cancer with Nutrition.