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Selenium is toxic in high concentrations. As sodium selenite, the chronic toxic dose for human beings was described as about 2.4 to 3 milligrams of selenium per day. [7] In 2000, the US Institute of Medicine set the adult Tolerable upper intake levels (UL) for selenium from all sources - food, drinking water and dietary supplements - at 400 μg/day. [8]
For example, selenomethionine and selenocysteine are selenium-containing amino acids present in the human body. Selenomethionine participates in the synthesis of selenoproteins . [ 2 ] The reduction potential and pKa (5.47) of selenocysteine are lower than those of cysteine , making some proteins have antioxidant activity. [ 3 ]
These are white, water-soluble solids. The decahydrate is a common ingredient in multivitamins and livestock feed as a source of selenium. The anhydrous salt is used in the production of some glass. Although the selenates are much more toxic, many physical properties of sodium selenate and sodium sulfate are similar. [2]
Selenomethionine is readily available as a dietary supplement. It has been suggested by nutritionists that selenomethionine, as an organic form of selenium, is easier for the human body to absorb than selenite, which is an inorganic form. [8] It was determined in a clinical trial that selenomethionine is absorbed 19% better than selenite. [8]
The chronic toxic dose of selenite for humans is about 2400 to 3000 micrograms of selenium per day for a long time. [20] Hydrogen selenide is an extremely toxic, corrosive gas. [ 21 ] Selenium also occurs in organic compounds, such as dimethyl selenide, selenomethionine , selenocysteine and methylselenocysteine , all of which have high ...
Owing to its similarity to sulfur-containing methionine, selenomethionine is mistaken for an amino acid by the yeast anabolism and incorporated in its proteins. It has been claimed that selenomethionine makes a better source of dietary selenium in animal nutrition, since it is an organic chemical compound sometimes found in some common crops ...
Some women may need to take iron, vitamin C, or calcium supplements during pregnancy, but only on the advice of a doctor. In the 1999–2000 National Health and Nutrition Examination Survey , 52% of adults in the United States reported taking at least one dietary supplement in the last month and 35% reported regular use of multivitamin ...
In the US, the popularity for vitamin E as a dietary supplement peaked around 2000, with popular doses of 400, 800 and 1000 IU/day. Declines in usage were attributed to publications of meta-analyses that showed either no benefits or negative consequences from vitamin E supplements.