What Is The Rda For Selenium?

The mineral selenium exists in a variety of foods, with the most abundant source coming from plants grown in selenium-rich soils, according to the National Institutes of Health. Deficiencies, though rare in the United States, affect your hair and nails, causing breakage and brittleness. Chronic deficiencies may lead to the development of hypothyroidism, some forms of heart disease and immune system weaknesses. The federal government's Institute of Medicine establishes recommended daily intakes that vary depending on your age and gender.

Function

The human body uses selenium for proper immune system functioning and regulating the thyroid, according to the National Institutes of Health. It also converts selenium from your food into antioxidants that can help your body repair cell damage caused by free radicals. These unbonded electrons are by-products of normal cell processes. Because they lack an electron, they scavenge your body's healthy cells and contribute to a variety of illnesses, such as Alzheimer's and heart disease.

Daily Intake Recommendations

The Institute of Medicine uses a range of recommended dietary allowances, or RDAs, for selenium. The recommended daily intake for adult males and females, age 19 and older, is 55 mcg, according to the National Institutes of Health. Pregnant women need 60 mcg daily, and lactating women require 70 mcg. Children between ages 14 and 18 also need 55 mcg, while those between ages 9 and 14 need 40 mcg. The IOM recommends 20 mcg for children between 1 and 3 and 30 mcg from ages 4 to 8. For infants, IOM suggests that 15 mcg is an adequate intake from birth to 6 months; for 6 months to 1 year, the adequate intake is 20 mcg. Selenium deficiency is rare in the United States. The average daily intake for adult men is 153 mcg, and for women, it averages 109 mcg, according to NIH.

Tolerable Upper Intake Levels

The Institute of Medicine has established tolerable upper levels of intake for selenium; these are parameters designed to prevent selenium toxicity. For adults and children over 14, the upper intake is 400 mcg daily. The recommended maximum intake for children ages 9 through 13 is 280 mcg; for ages 4 through 8, it is 150 mcg. The IOM recommends no more than 45 mcg for infants less than 6 months old and 60 mcg for those between 7 and 12 months.

Selenium Food Sources

Food sources that provide 100 percent or more of the adult requirement include Brazil nuts, with 543 mcg per 1 oz. serving; 1 cup of raw barley, with 75 mcg; and oysters, which provide 100 percent of the adult RDA, with 56 mcg. A standard serving of a variety of fish and shellfish species also meet the daily requirement for adults. These include orange roughy, tuna, shrimp, haddock, sole, flounder, halibut, salmon and rockfish, according to the U.S. Department of Agriculture. A 1-cup serving of turkey or chicken giblets and the average turkey neck also provide the adult RDA of 55 mcg.