Deficiency effects selenium

Asayama, K., Kooy, N.W. and Burr, I.M. (1986). Effect of vitamin E deficiency and selenium deficiency on insulin reserve and free radical scavenging systems in islets decrease of islet manganosuperoxide dismutase. J. Lab. Clin. Med. 107, 459-463. 

Excess selenium intake can occur in both animals and humans living in areas with elevated selenium in the soil. Most grass and grains do not accumulate selenium, but when an animal consumes plants that do accumulate selenium (some up to 10,000 mg/kg) they can develop a condition called the blind staggers . Symptoms include depressed appetite, impaired vision, and staggering in circles and can ultimately lead to paralysis and death. Humans are susceptible to similar effects as well as additional neurological effects. Selenium deficiency results in heart disorders, skeletal muscle effects, and liver damage. 

In five of six nondietary tumor-promotion experiments, sodium selenide significantly reduced the number of mice with tumors induced by 7,12-dimethyl-benzanthracene (DMBA)-croton oil (1). In these experiments, sodium selenide was applied concomitantly along with croton oil to female Swiss albino mice initiated with DMBA. Riley has also observed a reduction in DMBA-phorbol ester carcinogenesis by sodium selenide (2). The effect of selenium-deficient and selenium-adequate diets on DMBA-croton oil and benzopyrene skin carcinogenesis has also been studied. Supplemental dietary selenium inhibited both types of carcinogenesis. 

Pathological syndromes may result in muscular spasm, as seen in the exertional myopathies, or weakness, as seen in hyperkalemic periodic paralysis (HYPP). Similarly, infectious diseases may result in muscular rigidity (C. tetani infection (tetanus)) or paralysis (C. botulinum intoxication (botulism)). Overt rhabdomyolysis may result from the ingestion of the coccidiostats monensin, rumensin and lasalocid, or one of a number of plant mycotoxins. Dietary deficiencies of selenium or vitamin E have also been described as having severe deleterious effects on skeletal muscle health. 

Beilstein MA and Whanger PD (1989) Effects of vitamin B-6 deficiency on selenium metabolism in the rat. J Nutr 119 1962-1972. 

Thompson, H.J. Effect of deficiencies of selenium and vitamin E alone or in combination on the induction of mammary carcinogenesis by 1-methyl-1-nitrosourea Carcinogenesis 12 (1991) 2175-2179. 

The clinical relevance of selenium deficiency is more difficult to estabhsh than that of iodine deficiency. Moderate selenium deficiency is present in some regions of Europe, but it has not been associated with any cfinical condition in humans. Nonetheless, the degree of selenium deficiency in Finland was considered severe enough to implement a control program based on the supplementation of fertilizers with selenium (Aro et ai, 1995). New Zealand adopted the same strategy, because of the beneficial effects of selenium supplementation on the productivity of their animal industry. 

A number of other selenium proteins have been discovered in biological materials, but their function is not yet sufficiently known. For example, a selenium protein (17kDa) was found in rat sperm. It is interesting that high concentrations of selenium in male sexual organs are maintained in animals with selenium deficiency therefore, selenium compounds are likely to be important for reproductive function. Some anticarcinogenic effects are also attributed to this element. Selenium also reduces the toxic effects of arsenic, cadmium, mercury, thallium and tellurium. With arsenic, the mechanism of this protective effect is the formation of selenobis(S-glutathionyl)arsinium anion, which is formed in erythrocytes and excreted in bile (6-36). 

In 1956 selenium was identified (123) as an essential micronutrient iu nutrition. In conjunction with vitamin E, selenium is effective iu the prevention of muscular dystrophy iu animals. Sodium selenite is adrninistered to prevent exudative diathesis iu chicks, a condition iu which fluid leaks out of the tissues white muscle disease iu sheep and infertility iu ewes (see Eeed ADDITIVES). Selenium lessens the iacidence of pneumonia iu lambs and of premature, weak, and stillborn calves controls hepatosis dietetica iu pigs and decreases muscular inflammation iu horses. White muscle disease, widespread iu sheep and cattle of the selenium-deficient areas of New Zealand and the United States, is insignificant iu high selenium soil areas. The supplementation of animal feeds with selenium was approved by the U.S. EDA iu 1974 (see Eeed additives). Much of selenium s metaboHc activity results from its involvement iu the selenoproteia enzyme, glutathione peroxidase. 

Selenium deficiency has been identified iu humans iu a broad area of China, stretching from the northeast to the southwest. Two syndromes are evident Keshan disease, an endemic cardiomyopathy which affects children, and Kashin-Beck disease, an edemic osteoarthropathy (big-joiat), also mainly involving children, which occurs iu eastern Siberia and parts of China. As a result of these observations, a protective effect for selenium has been proposed, and various selenium-containing preparations have been appHed to preserve animal and human health. 

The risk of colon cancer appears to be inversely related to calcium and folate intake. Calciums protective effect may be related to a reduction in mucosal cell proliferation rates or through its binding to bile salts in the intestine, whereas dietary folate helps in maintaining normal bowel mucosa. Additional micronutrient deficiencies have been demonstrated through several studies to increase colorectal cancer risk and include selenium, vitamin C, vitamin D, vitamin E, and 3-carotene however, the benefit of dietary supplementation does not appear to be substantial.11... 

The synergistic effect observed in the presence of all three antioxidants implies that there is an interaction between the individual antioxidant components. The direct interaction of the a-tocopherol radical and ascorbic acid is already well established (Bisby and Parker 1995) and a study by Mayne and Parker (1989) on chicks deficient in vitamin E and selenium showed that the... 

There is a comparatively narrow concentration range separating effects of selenium deficiency from those of selenosis. 

---