Selenium is an essential trace mineral the human body requires in small amounts. The Office of Dietary Supplements of the National Institutes of Health recommends a daily intake of 55 mcg of selenium for individuals 14 or older. Pregnant and lactating women require 60 to 70 mcg daily, whereas infants and children require the mineral in smaller doses. Selenium plays an important role in human health and a deficiency can result in serious, often life-threatening conditions.
Sources of Selenium
Selenium occurs in different concentration levels in soils around the world. Plants obtain selenium from the soil in which they grow, and then transfer the mineral to animals that feed on them. The selenium levels in plants and animals in a given area depend on its concentration in the soil. Some good sources of selenium are Brazil nuts, tuna, beef, cod, turkey, grains, eggs, liver and chicken breast.
Brazil nuts have the highest selenium content, with an ounce providing up to 544 mcg, which is about 10 times more than the recommended daily intake. The Office of Dietary Supplements says it is best to avoid regular consumption of Brazil nuts to prevent selenium toxicity, which can cause mild damage to the nervous system, hair loss, tiredness and nausea.
Role of Selenium
Selenium may help reduce the risk of cancer, cardiovascular disease and many other chronic illnesses, notes the ODS. The body requires selenium to create selenoproteins, enzymes important to human health. Selenoproteins are antioxidants that protect cells from radical damage. These enzymes also aid muscle metabolism and thyroid function. Selenoproteins enhance male fertility by increasing sperm count and protecting sperms from oxidative damage. Selenium may also help shield the body from toxins found in contaminated food and water, heavy metals and other sources.
Causes of Selenium Deficiency
Low selenium levels in soil can cause selenium deficiencies in the local population. People with chronic illnesses who have been receiving intravenous feedings for a long time may also develop selenium deficiency. Another risk factor is impaired gastrointestinal functioning, which could be due to illnesses or surgeries. People on specialized medical diets low in selenium may also develop deficiency. If you are selenium-deficient, you may require supplementation to boost levels of the mineral in your body.
Risks of Selenium Deficiency
Selenium deficiency is rare in the United States, but is evident in some parts of China, Korea and Siberia, where the soil has low levels of selenium. Some of the ailments that afflict people in these areas include Keshan disease, Kashin-Beck disease and Myxedematous Endemic Cretinism. Keshan disease causes enlargement and abnormal functioning of the heart muscle. Kashin-Beck disease results in the degeneration of joint cartilage and can cause joint deformity and dwarfism in children. Myxedematous Endemic Cretinism is a disease that can lead to mental retardation. Selenium deficiency may also adversely affect thyroid functioning, lower immunity and aid the progress of viral infections.
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