Diet, selenium

A summary of the influence of selenium on deposition of mercury in rat tissues is presented in Table III. In the injection experiments, selenium caused a reduction in mercury deposition in the kidneys of rats given either inorganic or organic mercury. The reduction in kidney mercury is dependent upon the level of selenium injected and the chemical form of selenium (Fang, 1977). Selenomethionine was most effective in reducing the renal mercury content, followed by selenocystine, selenate, and selenite. In contrast to the kidneys, selenium usually resulted in an increased deposition of mercury in other tissues. It is of particular interest that selenium appears to be very effective in increasing methylmercury deposition in the brain. When included in the diet, selenium also causes an increased deposition of hepatic mercury. This is consistent with the results of selenium injection experiments. Deposition in the kidney may depend upon the level in the diet. At low mercury levels, selenium resulted in decreased levels in the kidneys but in increased levels at... 

Pure selenium deficiency, without concurrent vitamin E deficiency, is not generally seen except in animals on experimental diets (113). In China, selenium deficiency in humans has been associated with Keshan disease, a cardiomyopathy seen in children and in women of child-bearing ages, and Kashin-Beck disease, an endemic osteoarthritis in adolescents (113). 

Selenium plays a dual role in a living organism, depending on the compound and the amount adsorbed. Controlled small doses of some compounds are used in medicine and as diet supplements, for example, ca 0.1 ppm of diet dry matter for Hvestock (see Feed additives Mineral nutrients). Larger amounts can be toxic. 

Bakers inactive dry yeast is also widely used in the food industry. This yeast may be grown specifically as a food supplement and consequently there is a choice in its composition by varying growth conditions and feedstock makeup. It can possibly produce high levels of nicotinic acid and thiamin, the cmde protein content can be raised to 50—55% and it can be used as a vehicle for the incorporation of micronutrients such as selenium or chromium into the diet. 

Other agents, including selenium, vitamin E, lycopene, green tea, nonsteriodal anti-inflammatory agents, isoflavones, and statins, are under investigsation for prostate cancer and show promise. Selenium is a naturally occurring trace element that is an essential nutrient in the human diet.8 However, none of these agents is currently recommended for routine use outside a clinical trial. 

Some O-Se ligands are also known. A -, A--diet lr y 1 - A"- benzoy 1 se 1 eno ureato zinc has been characterized where the zinc is bidentately coordinated to the two ligands through the oxygen and selenium atoms, forming a distorted tetrahedral geometry.859... 

Day-old chicks fed selenium-deficient diets plus 100 mg Zn/kg FW, as zinc oxide, purified ration for 9 days Hens fed diets containing 218, 257, 1762, or 1861 mg Zn/kg diet for up to 40 weeks... 

Elzubeir, E.A. and R.H. Davis. 1988a. Effect of dietary sodium nitroprusside as a source of cyanide on the selenium status of chicks given diets of varying selenium concentration. Brit. Poult. Sci. 29 769-777. 

Palmer, I.S. and O.E. Olson. 1981. Effect of cyanide on selenium status in rats fed low selenium diets. Nutr. Rep. Inter. 24 635-641. 

Acute toxicity of paraquat in the domestic chicken was highly responsive to nutritional selenium status and not to Vitamin E status. As little as 0.01 mg Se/kg ration protected 8-day-old chicks against acute paraquat poisoning (Combs and Peterson 1983). Paraquat administered to chickens by way of diet was less toxic than the same amount administered in drinking water (Fletcher 1967). 

Acute oral LD50, diet deficient in Vitamin E and selenium (Combs and Peterson 1983)... 

---