Nutrient deficiency selenium

The development, maintenance, and optimal functioning of the immune system are dependent on balanced and adequate nutrition. However, either a deficiency or an excess of a number of nutrients can have adverse effects. The nutrients with the most pronounced effects in humans include amount and type of dietary fatty acids (FAs), protein energy malnutrition, vitamins A, B6, B12, C, and E, and minerals including zinc, copper, selenium, and iron. Multiple rather than single nutrient deficiencies... 

Nutrient deficiencies—Many animal studies have linked nutrient deficiencies, especially of the trace elements, to the development of cancer. Furthermore, deficiencies of vitamins A, C, E, and the B-complex vitamins have been associated with the increased susceptibility of chemically-induced tumors in animals, as have protein, iodine, iron, magnesium, and selenium deficiencies. 

It is noteworthy, too, that cataracts are one of the selenium deficiency symptoms noted in rats. " Many other injurious agents and nutrient deficiencies might also be eissociat with the formation of cataracts, so it is uncertain whether selenium deficiency is a frequent cause of this disorder. 

SELENIUMANDSELENIUMCOMPOUNDS] (Vol21) -from selenium deficiency [MINERAL NUTRIENTS] (Vol 16)... 

Selenium is a vital microelement for people. It has dual properties. Selenium is an essential nutrient at low concentration levels and it becomes toxic at higher concentration levels. Deficiency of selenium results in weakness and hard diseases. Selenium is a building material of many hormones and ferments it neutralizes free radicals, radioactive radicals in organism. The range of selenium safety concentration in food and water is very narrow. The daily normal amount of human consumption of selenium is 10-20 p.g, maximum safe concentration of selenium in water is 5-10 p.g/1. It becomes toxic at 20-30 p.g and bigger content in different objects. 

Adsorption of anions at mineral surfaces is important in soils because of the limit this process imposes on the availability of plant nutrients such as P, S, and Mo which occur naturally as anions and are added in anionic form in fertilizers. Anion adsorption is also relevant in geochemistry, ore processing, and other fields where minerals with high surface areas are brought into contact with aqueous solutions of anions. Selenite and goethite were chosen for this study because in Western Australia a selenium deficiency in pastures has been shown to be related to the incidence of white muscle disease in sheep (3), and according to workers quoted by Rosenfeld and Beath (9) selenium in soils of higher... 

Populations that are unusually susceptible to toxic effects of silver exposure are those that have a dietary deficiency of vitamin E or selenium, or that may have a genetically based deficiency in the metabolism of these essential nutrients. Individuals with damaged livers may also be more susceptible to the effects of silver exposure. In addition, populations with high exposures to selenium may be more likely to develop argyria. Furthermore, some individuals may exhibit an allergic response to silver. 

Vitamin E is required for normal growth and reproduction. The most important natural source is a-tocopherol found in plant oils and seeds. The ester form (e.g. vitamin E acetate) can be synthesized and is used for feed supplementation. One international unit is defined as being equivalent to the activity of 1 mg DL-a-tocopherol acetate. The nutritional role of vitamin E is closely interrelated with that of selenium and is involved mainly in the protection of lipid membranes such as cell walls from oxidative damage. Although these signs are similar to those of selenium deficiency, it is not possible to substitute selenium completely for vitamin E. Both nutrients are required in the diet. 

Within an endemic area the poorest subjects are likely to be at greatest risk, because their diet is likely to be the most deficient and the most contaminated by toxins. The association of KBD with a poorly diversified diet underlines the fact that this disease should be viewed as a nutritional disorder affecting a population deficient not only in iodine and selenium, but also in other nutrients. A prevalence of 66% of rickets in Tibetan children 24-months, of age or older has been reported in rural areas. The serum concentrations of 25-hydroxyvitamin D measured in 130 children were less than lOng/ml in 85% of them (Harris et al, 2001). Whether rickets, which appears in children 4—25 months, favors the occurrence of KBD that appears in children 5 years or older is an interesting hypothesis. 

Cyanide-nutrient interactions are reported for alanine, which appears to exacerbate cyanide toxicity, and for cystine, which seems to alleviate toxicity. Dietary cyanide - at levels that do not cause growth depression -alleviates selenium toxicity in chickens, but not the reverse. For example, dietary selenium, as selenite, at lO.Omg/kg for 24 days, reduced growth, food intake, and food utilization efficiency, and produced increased liver size and elevated selenium residues the addition of 45.0 mg CN/kg diet (100.0 mg sodium nitroprusside/kg) eliminated all effects except elevated selenium residues in liver. The mechanism of alleviation is unknown and may involve a reduction of tissue selenium through selenocyanate formation, or increased elimination of excess selenium by increasing the amount of dimethyl selenide exhaled. At dietary levels of 135.0 mg CN/kg plus 10.0 mg selenium/kg chick growth was significantly decreased. This interaction can be lost if there is a deficiency of certain micronutrients or an excess of vitamin K. 

Nutrition Failure to include nutrients in parenteral nutrition solutions can hardly be regarded as an adverse effect of the parenteral nutrition itself, but cases of nutritional deficiency continue to be reported in this way. These include iodine deficiency [20 ] and Wernicke s encephalopathy due to deficiency of vitamin Bi [21, 22 ]. Ffair loss during parenteral nutrition has variously been blamed on deficiencies of zinc, selenium, and biotin [23 ]. 

Recommended dietary allowances for a male adult (daily intake, in foods and food supplements) of some nutrients, usually the amounts estimated as needed to prevent overt manifestation of deficiency disease in most persons. For the substances listed in smaller amounts the optimum intake, leading to the best of health, may be somewhat greater. Not shown, but probably or possibly required, are the essential fatty acids, />aminobenzoic acid, choline, vitamin D, vitamin K, chromium, manganese, cobalt, nickel, zinc, selenium, molybdenum, vanadium, tin, and silicon. 

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