Alexander G. Schauss, PhD
AIBR Life Sciences Division
The word selenium comes from the Greek word, “selene”, which literally means “moon.” The wisdom of naming this element after the Greek word for moon is illustrated by the ability of pure selenium to increase its conductivity as much as a thousand fold when a sample is taken from pure darkness into bright sunlight. Hence, selenium compounds are used in the manufacture of many light-sensitive devices, from photocopy machines (xerography) to outdoor light sensors.
Selenium was only officially recognized as an essential trace element for human health in 1990. However, since then, a great deal of publicity has been given to this trace element. Selenium can:
- protect against harmful exposure to the heavy metal, mercury
- help make a vital antioxidant, glutathione
- help regulate male hormones
- in males, support prostate function
- work synergistically with vitamin E
- enhance immune function
Selenium has been described by some scientists as an “anti-cancer” nutrient. This is due to the fact that numerous studies have found that people living in areas rich in selenium in their soil and drinking water have lower rates of cancer than those people living in selenium-depleted soils.
A deficiency of Selenuim can contribute to many conditions, including:
- dry skin
- the development of cataracts
- affect the efficiency of vitamin E utilization
The is evidence that in males, maintaining adequate selenium levels may reduce the risk of prostate cancer, since it has been reported that males with prostate cancer have significantly lower levels of selenium. In females, evidence suggests that it may reduce menopausal symptoms, such as hot flashes, resolve dandruff, and help maintain a more youthful appearance of the skin. The best food sources of selenium are seafoods, kidney, liver, most red meats, unrefined grains, and fruits and vegetables grown in selenium-sufficient soil.
The current recommended dietary allowance (RDA) for selenium for healthy individuals consuming a mixed North American diet is:
- Infants 10 mcg.
- Children 20 mcg.
- Males (11-18) 50 mcg.
- Males (adults) 70 mcg.
- Females 55 mcg.
- Pregnant 65 mcg.
- Lactating (1st 6 mos.) 75 mcg.
(1) Shils, M.E. and Young, V.R. Modern Nutrition in Health and Disease, 7th Edition. Lea & Febiger: Philadelphia, 1988.
(2) Schauss, A. G. Minerals, Trace Elements and Human Health. Life Sciences Press: Tacoma (WA), 1996.
(3) Recommended Dietary Allowances, 10th Edition. National Research Council. National Academy Press: