"Selenium, 200mcg"

Selenium has a variety of functions but its main role is as an antioxidant. It is part of a nutritional antioxidant system that protects cell membranes and intracellular structural membranes from lipid peroxidation. This protection of the tissues and cell membranes may benefit the cardiovascular system and protect against cancer. We need adequate daily amounts of selenium for the maintenance of these antioxidant functions and for selenium's other cellular functions as well.

Selenium may also have anti-carcinogenic effects. The exact mechanism of action remains unknown. The most likely reason is related to its antioxidant action. However, some evidence suggests that selenium may decrease cell division or help cell repair.

Selenium also seems to protect us from the toxic effects of heavy metals and other substances. People with adequate selenium intake have fewer adverse effects from cigarette smoking, alcohol, oxidized fats, and mercury and cadmium toxicity. Aside from the likely antioxidant influence, the specific mechanism by which selenium affords this protection is not known, though the effect is confirmed by some research. Plant foods are the major dietary sources of selenium. The amount of selenium in soil determines the amount of selenium in the plant foods that are grown in that soil. Low soil levels of selenium are associated with higher cancer rates, and soil-rich areas have below-average cancer rates for a number of body systems, particularly the breasts, colon, and lungs. Selenium also can be found in some meats and seafood. In the U.S., meats and bread are common sources of dietary selenium. Some nuts, in particular Brazil nuts and walnuts, are also very good sources of selenium.

Selenium deficiency is most commonly seen in parts of China where the selenium content in the soil, and therefore selenium intake, is very low. Selenium deficiency is linked to Keshan Disease, a form of heart disease prevalent in children and is characterized by an enlarged heart and congestive heart failure, may be a direct result of selenium deficiency, as it has responded well to selenium treatment. People in Keshan, China, where the disease was discovered, treat it with a common herb called Astragalus, which accumulates selenium from the soil.

Selenium deficiency may also affect thyroid function because selenium is essential for the synthesis of active thyroid hormone. Researchers also believe selenium deficiency may worsen the effects of iodine deficiency on thyroid function, and that adequate selenium nutritional status may help protect against some of the neurological effects of iodine deficiency.