Studies Show Selenium Prevents Cancer and Thyroid Disease
by Melanie Grimes
Selenium is an essential trace mineral that forms an important part of our immune defense function, as well as a component in heart muscle. Found naturally in animal protein and vegetables, it is also found in fish, vegetables, and especially Brazil nuts. Its anti-oxidant functions have now been shown to reduce the risk of many cancers as well as thyroid disease, infertility and arthritis. There is even a suggestion that selenium alters genes that cause cancer.
Because selenium occurs naturally in the soil, organic crops will absorb it and transfer it into a form that is bioavailability to humans. The East Coast has selenium deficient soil, but the soil in the rest of the United States is rich in this mineral. To maintain the proper levels, supplementation is advised.
The effective form of selenium is L-selenomethionine, as this is the form most easily absorbed and stored in the body. This is also the form of this important mineral used in most clinical trials. Other forms, such as selenite, are not as easy for the body to assimilate.
Selenium has now been approved by the FDA for cancer reduction. "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, the FDA has determined that this evidence is limited and not conclusive." The statement that the results are" limited and not conclusive" is a major breakthrough for the health benefits of this nutrient.
In 2003 French study investigated the size of the thyroid gland compared to selenium consumption. Those with lower selenium levels in the blood had a larger thyroid, which can be a sign of goiter or thyroid disease. Researchers concluded that selenium may protect against both goiter and thyroid disease. An article in the medical journal Lancet (July 15, 2000) also commented on the importance of selenium to thyroid health, as well as fertility problems and heart disease.
Low selenium levels contribute to early miscarriage, thyroid disease, arthritis, and even viral infections. High blood levels of selenium have been shown to slow the replication of the HIV virus and those with low levels were 20 times more likely to die from AIDS than those with higher selenium levels.
A recent study in the Journal of the American Medical Association (JAMA) showed a 50 percent reduction in cancer deaths, including cancers of the lungs, colon and prostate. Early stage cancers were better halted, but age made no difference, as young and old alike benefited from selenium supplementation. Previous studies showed selenium effective against prostate cancer in volunteers with a history of skin cancer.
A double blind, randomized, placebo-controlled cancer prevention trial was published in 1997. Conducted at the University of Arizona, over 1300 patients with basal cell carcinomas were studied from 1983 to 1991 were given 200 mcg of selenium a day. The study showed a "significant reduction in total cancer mortality" 29 deaths compared to 57 in the placebo group. Incidences of cancer were reduced: only 77 people in the selenium group compared to 119 in the control. Also reduced were incidences of lung, colon and prostate cancer. No cases of toxicity occurred. The conclusion was that selenium supplementation did not protect against the development of further skin cancers, but it did preclude incidences of, and deaths from, other types of cancer. Recommended doses are about 40-70 mcg a day for an adult.