Selenium Description
Selenium -
Selenium is
an essential trace mineral in the human body. This nutrient is an
important part of antioxidant enzymes that protect cells against the
effects of free radicals that are produced during normal oxygen
metabolism. The body has developed defenses such as antioxidants to
control levels of free radicals because they can damage cells and
contribute to the development of some chronic diseases. Selenium is
also essential for normal functioning of the immune system and
thyroid gland. Plant foods are the major dietary sources of selenium
in most countries throughout the world. The amount of selenium in
soil, which varies by region, determines the amount of selenium in
the plant foods that are grown in that soil. Researchers know that
soils in the high plains of northern Nebraska and the Dakotas have
very high levels of selenium. People living in those regions
generally have the highest selenium intakes in the United States.
Soils in some parts of China and Russia have very low amounts of
selenium and dietary selenium deficiency is often reported in those
regions. Selenium also can be found in some meats and seafood.
Animals that eat grains or plants that were grown in selenium-rich
soil have higher levels of selenium in their muscle. In the United
States, meats and bread are common sources of dietary selenium. Some
nuts, in particular Brazil nuts and walnuts, are also very good
sources of selenium.
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