• KOREAN JOURNAL OF CROP SCIENCE
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• v.48
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• pp.13-23
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• 2003

The trace mineral, selenium (Se), is an essential nutrient of fundamental importance to human health. It is also very toxic and can cause Se poisoning (selenosis) in human and animals when its intake exceeds a suitable amount. Se functions within mammalian systems primarily in the form of solenoprotein. About 35 selenoproteins have been identified, though many have not yet been fully elucidated. Selenoproteins contain Se as selenocyseine (Sec) and perform variety of structural and enzymic roles; the enzymic roles are best-known as the antioxidants for hydrogen peroxides and lipid peroxides, and the catalysts for production of activity thyroid hormone. Glutathione peroxidases ($\textrm{GP}_X$) among the selenoproteins prevent the generation of free radicals and decrease the risk of oxidative damage to tissues, as does thioredoxin reductase (TR). TR also provides reducing power for several biochemical processes. Selenoproteins P and W are involved with oxidant defense in plasma and muscle, respectively, A selenoprotein is also required for sperm motility and may reduce the risk of miscarriage. Some epidemiological studies have revealed an inverse correlation between Se status and cardiovascular disease, and there is considerable evidence 1mm population com-parison data and animal studies that Se is anticarcinogenic. It is also suggested that Se should be needed for the proper functioning of the immune system, and appear to be a key nutrient in counteracting the development of virulence and inhibiting HIV progression to AIDS. As research continues, the role of selenium in the etiology of chronic diseases like appropriate medical nutrition therapy can be delivered and its effectiveness assessed. Se status in individuals is affected by diet and the availability of the Se. The Se content of plants is affected by the content and availability of the element in the soil in which they are grown, and so greatly varies from country to country, while the Se composition of meat reflects the feeding patterns of livestock. This paper provides an overview on Se as an essential trace mineral for human.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.3
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• pp.429-435
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• 1994

The effect of methionine (Met) supplementation on glutathione peroxidase(GSHPx) activity in young and 14 month-old rat and mice was investigated. GSHPx activity was more enhanced by methionine supplementation in young rats when selenium (Se) was given as selenite than given in the form of selenomethione (Se-Met). However, GSHPx activity was not influenced by Met supplementation in the old rats. When diets were low in Se, the biopotency of ht eenzyme by Met was facilitated. No significant differences in GSHPx activity was observed with Met supplement in growing mice when Met was given 0.3% and 0.8% iin the diet at high levels of Se (2 ppm). The peak GSHPx in liver and kidney occurred at day 18, thereafter it decreased. Particularly, the liver GSHPx at day 18 increased 4.2 times than that at day 4 by 0.5% Met supplementation, while the unsupplemented group remained only 2.5 times increase. It is considered that in some tissues Met requirement may be met by Se-Met when rats were fed a diet suboptimal in Met. In addition, at lower levels of Se the utilization of Se is more enhanced by Met than at higher levels of dietary Se. Therefore, GSHPx activity may be influenced greatly by Met status along with dietary Se.