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Adding this nutritional supplement to a normal diet could prevent cancer, heart disease, and strokes. Selenium is an essential trace element for health. Without it our ability to protect cell membranes from free radicals - those highly reactive compounds in cigarette smoke, fried foods, and radiation that damage our bodies - is severely compromised.

Selenium and the Immune System

Selenium is required for key functions within the thymus gland, the master control of our immune system. It is also important for proper white blood cell function. Selenium deficiency lowers resistance to infection because it impairs the ability of white blood cells and the thymus to fight off invading bacteria and viruses.

One study found that people who had normal selenium concentrations but who took selenium supplements showed a 118-percent increase in the ability of lymphocytes to kill tumour cells. There was also an 82-percent increase in the activity of natural killer cells, which destroy cancer cells and micro-organisms, apparently because selenium stimulates white blood cells to produce the powerful immune compound called interleukin-2.

Selenium and Cancer

Low levels of selenium have been linked to a higher risk for virtually all cancers. In contrast, selenium supplementation offers significant protection against cancers of the lung, colon, prostate, stomach, esophagus, and liver, and is associated with an overall 50-per-cent decrease in cancer mortality.

The clinical documentation of selenium as an anticancer nutrient began with a long-term cancer prevention trial that included 1,300 patients with skin cancer. The study found that selenium appeared to reduce the rate at which new skin tumours formed. Researchers were excited that a single nutritional supplement could prevent cancer. Would selenium work with other cancers?

To find out, the researchers expanded their study, one that was based upon the “gold standard” of scientific research: participants in a randomized, double-blind study took a tablet containing either 200 micrograms of selenium or placebo daily for four and one-half years and were followed for an additional six and one-half years. The outcome was so positive that researchers stopped the trial two years sooner than planned. The overall cancer rate was significantly lower in the selenium group than in the placebo group (77 cases versus 119) and the death rate from cancer was 50-per-cent less in the selenium treated group than the control group (29 versus 57).

Another study found that men consuming the most dietary selenium (assessed indirectly by measuring toenail selenium levels) developed 65-percent fewer cases of advanced prostate cancer than did men with the lowest levels of selenium intake.

Dosage and Side-Effects

The human body requires only 100 to 200 mcg of selenium each day. Larger dosages, as low as 900 mcg per day over prolonged periods of time, can produce selenium toxicity in some people, signs and symptoms of which include depression, nervousness, emotional instability, nausea and vomiting, a garlic odour of the breath and sweat, and, in extreme cases, loss of hair and fingernails.

What is the Best Form of Selenium?

Popular forms of selenium on the market include selenomethionine and high selenium content yeast. Sodium selenite is also available, but several studies have shown that as an inorganic salt it is less effectively absorbed.

Adding selenium to your diet is good health prevention for cancer, heart disease, and strokes.

Michael T. Murray, ND, is widely regarded as one of the world’s leading authorities on natural medicine. He is the author of more than 20 books, including the best-selling Encyclopedia of Natural Medicine (Prima Publishing, 1997).

Source: alive #260, June 2004