Absorption
Selenium, in organic and inorganic forms, is efficiently absorbed. The duodenum appears to be the primary absorptive site, with some absorption also occuring in the jejunum and ileum.
Selenoamino acid absorption, which occurs through amino acid transport systems, is estimated to be over 80%. Selenomethionine is thought to be better absorbed than selenocysteine.
Factors Influencing Selenium Absorption
Vitamin C, A, and E, as well as the presence of reduced glutathione in the intestinal lumen.
Heavy metals (such as mercury) and phytates are thought to inhibit selenium absorption through chelation and precipitation.
Uptake& Storage
The mechanism by which selenium is freed from plasma transport proteins and taken up by tissue is not known. The uptake of selenium by one of the main selenium-containing metalloenzymes, glutathione peroxidase.
That is, ingesting selenium in inorganic forms, such as selenite, cause more of the mineral to be incorporated into glutathione peroxidase than ingesting the organic form, selenomethionine, does.
Selenium, in organic and inorganic forms, is efficiently absorbed. The duodenum appears to be the primary absorptive site, with some absorption also occuring in the jejunum and ileum.
Selenoamino acid absorption, which occurs through amino acid transport systems, is estimated to be over 80%. Selenomethionine is thought to be better absorbed than selenocysteine.
Factors Influencing Selenium Absorption
Vitamin C, A, and E, as well as the presence of reduced glutathione in the intestinal lumen.
Heavy metals (such as mercury) and phytates are thought to inhibit selenium absorption through chelation and precipitation.
Uptake& Storage
The mechanism by which selenium is freed from plasma transport proteins and taken up by tissue is not known. The uptake of selenium by one of the main selenium-containing metalloenzymes, glutathione peroxidase.
That is, ingesting selenium in inorganic forms, such as selenite, cause more of the mineral to be incorporated into glutathione peroxidase than ingesting the organic form, selenomethionine, does.
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