Selenium

About: Selenium is a research topic. Over the lifetime, 21192 publications have been published within this topic receiving 429715 citations. The topic is also known as: Se & selen.

Total diet study nutritional elements, 1982-1989.

Abstract: Daily intakes of sodium, potassium, calcium, phosphorus, magnesium, iron, zinc, selenium, iodine, copper, and manganese for eight age-sex groups are presented for 1982 to 1989. Compared with the intakes recommended by the National Academy of Sciences, sodium intakes (which did not include discretionary salt) exceeded the estimated minimum requirement; intakes of potassium, phosphorus, selenium, and iodine were adequate for all groups; and copper intakes were low (less than 80% of the suggested intake) for all groups. In addition, calcium, magnesium, iron, and manganese were low in the diets of teenage girls; calcium, magnesium, and iron were low in the diets of adult women; calcium, magnesium, and zinc were low in the diets of older women; calcium and zinc were low in the diets of 2-year-olds; and magnesium was low in the diets of teenage boys and older men. The primary food group source for each element was dairy products for potassium, calcium, phosphorus, magnesium, and iodine; grain products for sodium, iron, and manganese; and animal flesh for zinc, selenium, and copper.

Dietary Selenium Intake Controls Rat Plasma Selenoprotein P Concentration

Abstract: The purpose of this study was to determine the effect of dietary selenium on selenoprotein P concentration. Selenoprotein P was quantitated in plasma by radioimmunoassay. Selenium-dependent glutathione peroxidase activity in plasma and liver 105,000 x g supernatant was measured for comparison. Weanling male rats were fed a selenium-deficient diet or a control diet that contained 0.5 mg selenium/kg as Na2SeO4. The concentration of selenoprotein P fell at approximately the same rate in the rats fed the selenium-deficient diet as did plasma glutathione peroxidase activity. Groups of weanling rats were fed different levels of selenium for 8 wk. Selenoprotein P concentration was proportional to dietary selenium level up to 0.1 mg/kg and was a greater percentage of control values than was glutathione peroxidase activity. No increment in selenoprotein P concentration occurred between 0.1 and 0.5 mg selenium/kg diet. These results indicate that the concentration of selenoprotein P in the plasma is directly dependent on selenium supply in the diet up to 0.1 mg/kg. There is overlap between the dietary selenium ranges in which selenoprotein P concentration and glutathione peroxidase activity increase, but the selenoprotein P range is lower than the glutathione peroxidase range.

The dual effects of two inorganic selenium forms on the growth, selected physiological parameters and macronutrients accumulation in cucumber plants

Abstract: The boundary between beneficial and phyto- toxic levels of selenium (Se) is narrow, and both induce alteration in plant growth and their physiology. In this study, the influence of two Se forms (selenite or selenate) with different concentrations (2-80 lM) on cucumber plants was investigated. The toxicity threshold for selenate and selenite was determined at the concentrations of 80 and 20 lM, respectively. In the Se-exposed plants, the growth- promoting effect was found at 6 lM of selenite and at 6-20 lM of selenate. The root activity considerably increased with increasing selenite concentrations suggest- ing the upregulation of mitochondrial dehydrogenases activity. Selenite treatment also impaired photosynthetic pigments accumulation and chlorophyll fluorescence parameters. Moreover, Se exerted a dual effect on lipid peroxidation in roots: at low concentrations it inhibited this process, whereas at high concentrations it enhanced the accumulation of harmful lipid peroxides. Under low Se concentrations (\10 lM), the accumulation of Se in shoots was similar in the presence of selenate and selenite. When Se concentration was (10 lM, the accumulation of Se in shoots was greater in selenate-exposed than selenite- exposed plants. However, in the roots the Se concentrations were always higher after selenite exposure comparing to selenate. The N level in plants was generally maintained constant, while the remaining macronutrients (especially K, P, and S) concentrations were significantly changed depending on the form and concentrations of Se. These results imply that an application of either selenate or sel- enite at concentrations\10 lM may be potentially used for biofortification of cucumber with Se and changes in plant macronutrient contents are not expected under these conditions.