Selenium daily intake

An endemic disease in China, characterized by loss of hair and nails, skin lesions, and abnormalities of the nervous system, including some paralysis and hemiplegia, was attributed to chronic selenium poisoning. The daily intake for six affected individuals averaged 5.0mg versus 0.1 mg for people from an unaffected area. Changing the diet led to... 

Selenium is readily available in a variety of foods including shrimp, meat, dairy products, and grains, with a recommended daily intake of 55 to 70 jug. It occurs in several forms with Se+6 being biologically most important. Selenium is readily absorbed by the intestine and is widely distributed throughout the tissues of the body, with the highest levels in the liver and kidney. It is active in a variety of cellular functions and interacts with vitamin E. Selenium appears to reduce the toxic effects of metals such as cadmium and mercury and to have anticarcinogenic activity. Selenium produces notable adverse effects both in deficiency and excess thus recommended daily intake for adults is approximately 70 Jg/day but should not exceed 200 pg/day. 

Synthroid is a man-made synthetically manufactured version of T-4/L-thyroxine. The average person produces about 76 MCG/d of T-4/L-thyroxine which is then converted by the liver into the more active T-3/L-triiodothyronine. This is true of the oral T-4/L-thyroxine medications as well. The average conversion rate of T-4 to T-3 is about 30-33%/ MCG. Since the conversion of T-4 to T-3 is dependent upon adequate levels of since and selenium, athletes commonly increase daily intake of these minerals during synthetic T-4/L-thyroxine use. 

Organization guidelines for drinking water quality (World Health Organization, 1984) include limit values for the organic and toxic substances (see Table 11.6), based on acceptable daily intakes (ADI). These can be adopted direcdy for ground-water protection purposes, but in view of the possible accumulation of certain toxic elements in plants (e.g. cadmium and selenium), the intake of toxic materials... 

Smrkolj, P, Pograjc, L., Hlastan-Ribic, C., and Stibilj, V. 2005. Selenium content in selected Slovenian foodstuffs and estimated daily intakes of selenium. Food Chemistry, 90 691-7. 

Hussein, L., Bruggeman, J. Selenium analysis of selected Egyptian foods and estimated daily intakes among a population group. Food Chem. 65, 527-532 (1999)... 

The major functions of selenium can be attributed to its antioxidative properties and its role in the regulation of thyroid hormone metabolism. Selenium is important as a nutritional factor, and the US Food and Nutrition Board s Committee on Dietary Allowances has, perhaps somewhat arbitrarily, proposed a recommended daily intake of 50-200 micrograms/day. 

Low levels of selenium can also be found in drinking water. Most of the water sources tested in the United States have very low levels of selenium compared with the levels found in food. Selenium levels were less than 10 ppb (10 parts of selenium in a billion parts of water) in 99.5% of drinking water sources tested. The 10-ppb concentration is lower than the 50-ppb Maximum Contaminant Level (MCL), which the EPA believes will protect against adverse health effects. Less than 1% of the daily intake of selenium is estimated to come from drinking water. 

Sakurai H, Tsuchiya K. 1975. A tentative recommendation for the maximum daily intake of selenium. Environ Physiol Biochem 5 107-118. 

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. 

The selenium content in humans is 10-15 mg, while the daily intake is 0.05-0.1 mg. Depending on the region, it can vary greatly because of the varying content of selenium in the soil. Selenium is an antioxidant and can enhance tocopherol activity. The enzyme glutathione peroxidase contains selenium. It catalyzes the following reaction, protecting membranes from oxidative destruction ... 

The actual daily intake of selenium in the diet varies in different countries and depends on many factors. For example, the following amounts were determined 330 p,g in Venezuela, 130 200 p,g in Canada, 80-130 p,g in the United States, about 60 p,g in Great Britain, in Finland 30-40 p,g (in the 1970s) and in New Zealand 23-33 p,g. For example, the mean selenium intakes in the United... 

Supplementation with the antioxidant vitamins ascorbic acid (250 mg) and mixed natural tocopherols (50 IU on alternate days) may be beneficial. Higher doses may vitiate the impact of lipid lowering therapy. Other naturally occurring antioxidants such as resveratrol, 3-catechin, selenium, and various carotenoids found in a variety of fruits and vegetables may provide additional antioxidant defense. Homocysteine, which initiates proatherogenic changes in endothelium, can be reduced in many patients by restriction of total protein intake to the amount required for amino acid replacement. Daily supplementation with up to 2 mg of folic acid plus other B vitamins is also recommended. 

F. Li, E. Rossipal, K. J. Irgolic, Determination of selenium in human milk by hydride cold-trapping atomic absorption spectrometry and calculation of daily selenium intake, J. Agric. Food Chem., 47 (1999), 3265-3268. 

Gao, J., Liu, Y., Lin, Z.-Q., Banuelos, G.S., Lam, M., and Yin, X.B. In press. Daily dietary intake of selenium in Suzhou Industrial Park, China. Selenium Deficiency, Toxicity, and Biofortification for Human Health. USTC Press. 

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