Selenium is as essential trace mineral and functions as part of the antioxidant enzyme glutathione perioxidase. It is bonded to the essential sulfur amino acid, methionine, in a naturally occurring form as found in the diet. Selenium is found most abundantly in Brazil Nuts, organ meats, seafood, and wheat germ.*

Question:
Someone recently told me that taking selenium supplements is beneficial. He made it sound like it could reduce the risk of some cancers by 50% or more, which sounds too good to be true. Is it?

Answer:
It may be true. A study published in the Journal of the American Medical Association in 1996 found that people taking 200 micrograms of selenium a day for over four years had a 46% lower risk of lung cancer, 63% lower risk of prostate cancer, and 58% reduction in colorectal cancer. Overall, the cancer risk dropped by 37% compared to people taking a placebo.

If a pharmaceutical company came out with a drug that could reduce the risk of cancer to this degree, then just about every doctor in the country would prescribe it. You would likely find full-page ads in newspapers and magazines: "Ask your doctor for this new drug." Sometimes, when I lecture, I'll ask people how many were prescribed selenium by their physicians, and very few raise their hands.

Any time a new therapy comes along, the most important questions to ask are, "What is the scientific evidence that it is effective? What are the potential side effects? How much does it cost?" Physicians sometimes refer to this as the "risk/benefit ratio." In the case of selenium, the potential benefit is great, the cost is very low, and the side-effects and risk are very low. Although this study needs to be replicated, the potential benefits are so great and the risks and costs are so low, I now recommend selenium for most people. Selenium was first linked with reduced cancer risk in the 1960s. Theories about how the trace element could work to prevent tumors include the following: it may act as an antioxidant; it may be able to alter how the body processes carcinogens; it may have an effect on how proteins are made; or selenium may play a role in how the immune system functions.

From the FDA's website:
"Selenium may reduce the risk of certain cancers. Some scientific evidence suggests that consumption of selenium may reduce the risk of certain forms of cancer. However, FDA has determined that this evidence is limited and should be revisited."

High antioxidant intake, including selenium and tocopherol, has been shown to protect against chronic diseases.

The research showed that nearly 40 per cent of the sample population failed to reach the desirable levels of serum selenium concentrations, (less than 1.1 micromoles per litre), despite eating healthily.

The study followed the diet of 178 women with an average age of 63 over a three-day period. Blood samples were taken to determine the serum levels of the antioxidants.
The results show that low serum alpha-tocopherol and selenium concentrations are highly prevalent even among well-educated and well-nourished German women,” said the scientists.

“This result indicates that...women with low selenium antioxidant levels would possibly benefit from an additional intake of selenium,” recommended the researchers.
It is believed that selenium and alpha-tocopherol work together to inhibit lipid peroxidation. “Insufficient status of one of these nutrients may elevate the risk of oxidative stress and possibly for associated diseases,” explained the researchers.

Results published in the Archives of Internal Medicine (2004, Vol. 164, pp. 2335-2342) indicated that supplementation of diet with antioxidants may lower the risk of cancers. Another study, published in the American Journal of Clinical Nutrition (Vol. 80, pp. 154-162), reported that increased selenium intake could boost the immune system.

These reports add to the growing body of evidence for the health benefits of selenium intake. There have even been recommendations to enrich soil and fertilizers with selenium to boost public consumption.