Definition Selenium is an essential mineral that works as part of an important antioxidant enzyme. The body only needs a very small amount of selenium. The amount is measured in micrograms (mcg). The highest concentrations of selenium in the body are found in the liver, kidney, heart, and spleen.
What food source is the nutrient found in? Good sources of selenium include:
lean red meat
whole (unrefined) grains
some nuts and seeds
The amount of selenium in food depends on the amount of selenium in the soil those foods were grown in. The amount of selenium in some foods is:
low-fat milk (1 cup) = 3.6 mcg
whole-grain cereal (1 serving) = 12.3 mcg
seafood (100 grams) = 37.9 mcg
How does the nutrient affect the body? Selenium's main role is as part of an antioxidant enzyme called glutathione peroxidase. Selenium works with the antioxidant vitamin E. Adequate amounts of selenium can reduce the need for vitamin E. They work together to protect the body's cells from free radicals. Free radicals cause damage that can lead to cancer, heart disease, and other health problems. Selenium is essential for normal development of the foetus during pregnancy. It may also protect from the toxic effects of heavy metals, such as lead poisoning.
Information Scientists are studying a possible link between cancer and low selenium intake. Those with liver disorders seem to have low levels of selenium when compared to people with healthy liver function. People with breast cancer also have lower levels of selenium than do healthy subjects. In theory, selenium protects against both cancer and heart disease. This is because it is an antioxidant.
The adult recommended daily intakes, or RDI, for selenium are:
Getting too much selenium is not healthy. High levels of selenium can cause nausea, vomiting, fatigue, hair and nail loss, lesions of the skin and nervous system, and possibly damage to teeth.
Author: Kimberly Tessmer, RD, LD Reviewer: eknowhow Australia Medical Review Panel Editor: Dr John Hearne Last Updated: 8/11/2004 Contributors Potential conflict of interest information for reviewers available on request
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