Effects of Selenium Excesses

Combs, Gerald F.

doi:10.1016/b978-0-12-183495-1.50016-6

Cited by 10 publications

(4 citation statements)

References 155 publications

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“…Most of these have involved occupational exposures (e.g. workers in Cu smelters or Serectifier plants) due to the inhalation of Se-containing aerosols; some have involved the accidental oral consumption of various inorganic Se compounds (Combs & Combs, 1986d;Lombeck et al 1987b;Gasmi et al 1997). There has been one instance in which an over-the-counter supplement was erroneously formulated with excessive Se.…”

Section: Selenosismentioning

confidence: 99%

Selenium in global food systems

2001

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Food systems need to produce enough of the essential trace element Se to provide regular adult intakes of at least 40 m g/d to support the maximal expression of the Se enzymes, and perhaps as much as 300 m g/d to reduce risks of cancer. Deprivation of Se is associated with impairments in antioxidant protection, redox regulation and energy production as consequences of suboptimal expression of one or more of the Secontaining enzymes. These impairments may not cause deficiency signs in the classical sense, but instead contribute to health problems caused by physiological and environmental oxidative stresses and infections. At the same time, supranutritional intakes of Se, i.e. intakes greater than those required for selenocysteine enzyme expression, appear to reduce cancer risk. The lower, nutritional, level is greater than the typical intakes of many people in several parts of the world, and few populations have intakes approaching the latter, supranutritional, level. Accordingly, low Se status is likely to contribute to morbidity and mortality due to infectious as well as chronic diseases, and increasing Se intakes in all parts of the world can be expected to reduce cancer rates.

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Section: Selenosismentioning

confidence: 99%

Selenium in global food systems

2001

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“…workers in Cu smelters or Se-rectifier plants, due to the inhalation of Se-containing aerosols. Other cases have involved the accidental oral consumption of various inorganic Se compounds [14,15,16]. An acute exposure to Se high levels may result in hypotension, respiratory distress and a garlic-like smell of the breath.…”

Section: Selenium: History Natural Forms Toxicity and Functionsmentioning

confidence: 99%

Selenium and Selenoproteins: An Overview on Different Biological Systems

Mangiapane¹,

Pessione²,

Pessione

2014

CPPS

141

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Selenium (Se) is an essential trace element for humans, plants and microorganisms. Inorganic selenium is present in nature in four oxidation states: selenate, selenite, elemental Se and selenide in decreasing order of redox status. These forms are converted by all biological systems into more bioavailable organic forms, mainly as the two seleno-amino acids selenocysteine and selenomethionine. Humans, plants and microorganisms are able to fix twhese amino acids into proteins originating Se-containing proteins by a simple replacement of methionine with selenomethionine, or "true" selenoproteins if the insertion of selenocysteine is genetically encoded by a specific UGA codon. Selenocysteine is usually present in the active site of enzymes, being essential for their catalytic activity. This review will focus on the strategies adopted by the different biological systems for selenium incorporation into proteins and on the importance of this element for the physiological functions of living organisms. The most known selenoproteins of humans and microorganisms will be listed highlighting the importance of this element and the problems connected with its deficiency.

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“…As an essential element, Se is a component of glutathione peroxidase [1,2,11]. Acute human selenium toxicosis has been reported from industrial and other accidental exposures [2].…”

Section: Introductionmentioning

confidence: 99%

“…As an essential element, Se is a component of glutathione peroxidase [1,2,11]. Acute human selenium toxicosis has been reported from industrial and other accidental exposures [2]. However, it has been known that there is a relatively narrow range between levels of selenium intake resulting in deficiency and those causing toxicity, resulting in a very narrow margin of safety [4].…”

Section: Introductionmentioning

confidence: 99%

Absorption and Distribution for Subtoxic Level of Selenite by Vascularly Perfused Small Intestine in Rats

Park¹,

Yoon²,

Kim³

2010

Journal of Life Science

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Intestinally absorptive and distributive aspects of the subtoxic level of selenite in rats were investigated using a double perfusion system. The double-perfusion technique is an in situ, in vitro preparation in which the intestinal lumen and its vasculature are perfused simultaneously. In the previous study, the subtoxic level of sodium selenite was determined to be 1.2 mM through inhibition of 3-0-methyl glucose (3MG) absorption. Thus, the selenite used to identify the intestinally absorptive mechanism of selenite was perfused at a luminal concentration of 1, 10, 50, 100 and 200 μM. Appearance of radiolabeled-Selenium (Se) was identified in three compartments: luminal perfusate, small intestine and vascular perfusate. Dose-response curves for Se in the three compartments indicate that selenite is absorbed by non-mediated passive diffusion. Regarding the distributive aspect, 21.02±3.92% of the total amount of selenite in the lumen was transported into the blood vessels across the small intestine. However, 4.75±1.75% of the total amount of selenite in the lumen is retained by the small intestine. Therefore, a total of 25.67±4.46% of the test dose was taken up from the luminal perfusate.

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Effects of Selenium Excesses

Cited by 10 publications

References 155 publications

Selenium in global food systems

Selenium in global food systems

Selenium and Selenoproteins: An Overview on Different Biological Systems

Absorption and Distribution for Subtoxic Level of Selenite by Vascularly Perfused Small Intestine in Rats

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