The Moon Goddess’ Role in Human Health by Donald W. Miller, Jr., MD

Out of the 92 elements that exist in nature, 25 make up the human body. The largest one is iodine (atomic weight 126.9), followed by molybdenum (95.9). Selenium (78.96) is third.


Selenium was discovered in 1817 and named after Selene, the Greek Goddess of the Moon. This element is a member of the Group 16 (VIA) family of elements in the periodic table, along with oxygen, its sister sulfur, and the metalloid elements tellurium and polonium. Soil contains selenium in minute and variable amounts. The concentration of selenium in the earth’s crust is less than that of gold. Plants take up selenium from the soil and propagate it through the food chain. Brazil nuts, in particular, like selenium. Selenium was identified as an essential trace element for mammals in 1957, and investigators now have determined that the cells of all organisms, bacterial, animal, and non-animal, need selenium.


Two amino acids, among the 20 that the body uses to make proteins, contain sulfur – methionine and cysteine. Selenium has similar chemistry and replaces the sulfur atom in these amino acids. Selenocysteine, selenium bound to cysteine, a "21st" amino acid, is the active site in some 35 proteins. Several are enzymes. Glutathione peroxidase, with four selenium atoms, is a powerful antioxidant. Iodothyronine deiodinase converts the thyroid hormone T4 (thyroxine) into its active form T3 (triiodothyronine). Since this enzyme requires selenium to function properly a deficiency of selenium can cause hypothyroidism. Thioredoxin reductase regenerates antioxidant systems and regulates gene expression. All living things contain this selenium-dependent enzyme (Protein Sci 2003;12:372–378).


The proteins that selenium seed have antioxidant, anti-inflammatory, and immune enhancing properties that altogether foster a long, healthy life. Selenium blood levels tend to fall as people age. In one study, investigators followed 1,300 people age 60–71 years for 9 years and found that those with the greatest decrease in blood selenium had the highest likelihood of cognitive decline. The same study showed that people with a low selenium blood level also had a shorter life span.


A growing body of evidence indicates that selenium can prevent cancer. Studies show that low selenium blood levels are associated with an increased risk of cancer. One done in Finland showed that people with low selenium bloods levels are much more likely to develop lung cancer, especially if they smoke, than smokers and nonsmokers with high selenium levels.


Another one, the Harvard Health Professionals Cohort study in 34,000 men, found that men with the lowest selenium levels had three times the likelihood of developing advanced prostate cancer compared with those who had the highest levels. These and other epidemiological, cohort, and case control studies suggest that selenium plays a role in cancer prevention. Now, however, there is strong scientific evidence that selenium does indeed reduce the risk of cancer. Evidence from a well-conducted randomized, placebo-controlled, double-blind trial proves beyond a reasonable doubt that this is the case.


The Nutritional Prevention of Cancer (NPC) trial recruited 1300 patients with nonmelanoma skin cancer who were randomized to receive 200 mcg of selenium a day or a placebo for a mean 4½ years. Selenium decreased the overall incidence of all cancers by 35% and cancer mortality by 50%. Prostrate cancer decreased by 63%; colorectal cancer, by 58%; and the incidence of lung cancer decreased by 46%.


Antioxidant protection and enhanced immune surveillance are two mechanisms researchers have proposed to account for selenium’s anticancer effect. Others include enhancement of apoptosis (programmed cell death), regulation of cell proliferation, suppression of angiogenesis (growth of blood vessels supplying nutrients to the cancer), and inhibition of tumor cell invasion.


In 2000, the U.S. Food and Nutrition Board (in the Institute of Medicine) revised the Recommended Dietary Allowance (RDA) for selenium, setting it at 55 mcg per day (it had been 70 mcg/day for men and 55 mcg/day for women). This is the "nutritional" dose, said to be adequate for 98 percent of the population. It is based on two studies that show this amount of selenium supports the maximal expression of glutathione peroxidase, which is regarded as fully discharging the nutritional effects of this element. A supranutritional dose is one that is 5 to 10 times higher than the RDA and not toxic. The government-funded experts who set the RDA for selenium did not take into account the NPC trial results, reported in 1996, four years earlier, that shows that a dose four times higher (200 mcg) has an anticancer effect.


A recently published study in the Annals of Internal Medicine, which does not like supplements, warns that selenium “may” increase the risk for type 2 diabetes. This study is badly flawed. One of its major defects, among others, is that the investigators did not do any blood tests for diabetes at the start of the trial (where subjects were randomized to take selenium or a placebo) and relied simply on what the study subjects told them. Only 4% said that they had diabetes, whereas the true prevalence of diabetes in people their age, >60 years old, is 16.0% in men and 14.4% in women; and undiagnosed diabetes is present in an additional 7.9% of men and 4.2% women (Diabetes Care 2006;29(6):1263–1268). This study is not credible and is no cause for alarm. People with diabetes can take selenium without being concerned that it might make their diabetes worse.


The Moon Goddess’ element has other beneficial effects on human health. The heart does not function well without selenium. Heart failure can occur after weight loss (bariatric) surgery due to selenium deficiency resulting from malabsorption, which resolves when selenium is administered intravenously (J Trace Elements Med Biol 2004;18:81–88). And researchers have shown that selenium helps the heart recover after it is temporarily deprived of oxygen, something surgeons do in performing heart surgery.


Selenium stimulates the immune system and has been shown to be effective in treating sepsis (blood stream infection). Studies show that it increases the number of T cells circulating through the body, both CD4 helper T cells and CD8 cytotoxic (killer) T cells. Even given a good dietary intake (120–134 mcg/day), selenium supplementation still has considerable immunoenhancing effects.


Selenium also affects male fertility. It is required for synthesis of testosterone and to keep sperm structurally intact. Experts in animal husbandry recognize that selenium is essential for successful reproduction. In the U.S., soil scientists reckon that selenium deficiency is a major problem for livestock and wildlife in at least 37 states.