Keshan disease, selenium deficiency

Keshan disease (selenium deficiency) Sickle cell anaemia... 

Selenium is an essential element and is beneficial at low concentrations, serving as an antioxidant. Lack of selenium affects thyroid function, and selenium deficiencies have been linked to Keshan Disease (34). Selenium at high levels, however, is toxic. Hydrogen selenide (which is used in semiconductor manufacturing) is extremely toxic, affecting the mucous membranes and respiratory system. However, the toxicity of most organ oselenium compounds used as donor compounds for organic semiconductors is not weU studied. 

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 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. 

Seleninm in this form is present in three enzymes glutathione peroxidase, iodothyronine deiodinase and thio-redoxin rednctase. Deficiency of selenium therefore decreases the activity of these three enzymes and resnlts, at least in experimental animals, in liver necrosis and mns-cnlar dystrophy. In hnmans, it is known to be a canse of a particnlar form of cardiomyopathy known as Keshan disease which affects children and women. This cardiomyopathy was first described in China in 1979. It is also considered that a deficiency of selenium is a risk factor for cancer. 

In 1957, Schwartz and associates showed that the toxic element selenium was also a nutritional factor essential for prevention of the death of liver cells in rats.527 Liver necrosis would be prevented by as little as 0.1 ppm of selenium in the diet. Similar amounts of selenium were shown to prevent a muscular dystrophy called "white muscle disease" in cattle and sheep grazing on selenium-deficient soil. Sodium selenite and other inorganic selenium compounds were more effective than organic compounds in which Se had replaced sulfur. Keshan disease, an often fatal heart condition that is prevalent among childen in Se-deficient regions of China, can be prevented by supplementation of the diet with NaSe03.528 Even the little crustacean "water flea" Daphnia needs 0.1 part per billion of Se in its water.529... 

Keshan disease -from selenium deficiency [MINERAL NUTRIENTS] (Vol 16)... 

In contrast, selenium deficiency has been implicated in several human diseases, most notably Keshan disease (KD) and Kashin-Beck disease (KBD). KD is an endemic selenium-responsive cardiomyopathy that mainly affects children and women of child-bearing age and is named after... 

RNA genome codes for four proteins. Three of these proteins are virus capsule proteins (they coat the RNA), and one of these proteins is a viral protease. The virus can cause temporary fever and sore throats in children however, about 5% of infections in adults and children result in damage to the heart, It is thought that Keshan disease In China, which is associated with selenium-deficient populations, is due to some influence of the selenium deficiency on the activation of coxsackievirus Studies with nrtice have revealed an interesting phenomenon. One particular strain of coxsackievirus can infect mice, but does not result in much hann to the mice. However, when the mice arc raised on an Sc-deficient diet, the virus acquires mutations in its genome and produces damage to the mouse s heart (Beck t ai., 1995). 

Severe Deficiency. Symptomatic selenium deficiency has been well characterized in Keshan disease and nutritional depletion in hospital patients. 

Biomarkers of Deficiency. Two endemic diseases, Keshan disease and Kashin-Beck disease, have been reported in selenium-deficient populations in China in which mean hair, blood, and urine selenium levels are low (Yang et al. 1988). Keshan disease, manifested as nausea, vomiting of yellowish fluid, and necrosis of the myocardium, has been found in a population with an average whole blood selenium concentration of 0.018 mg selenium/L, an average urinary concentration of 0.007 mg selenium/L, and an... 

Yang GQ. 1985. Keshan disease An endemic selenium-related deficiency disease. In Chandra, ed. Trace Elem Nutr Child Nestle Nutr. Vol. 8. New York, NY Raven Press, 273-290. 

Keshan disease (KD), a fatal cardiomyopathy endemic in central China and adjacent parts of Russia, was the first human disease to be associated with selemum deficiency. In the endemic regions the average selenium intakes ranged from only 3 to 11 tg per... 

Selenium deficiency has been associated with specific diseases in China and Africa Keshan and Kashin-Beck disease (KBD) in Tibet and China and myxedematous cretinism in Central Africa. Interestingly, in all these selenium-deficient areas iodine deficiency is also endemic. The specific impact of iodine deficiency on human health is described elsewhere in this book and will not be repeated here, with the exception of health conditions where the interaction of iodine and selenium may contribute to the pathogenesis of a specific disease. This chapter will deal with diseases where both iodine and selenium deficiency play a role in disease causation and particularly with KBD. 

The geographical distribution of KBD and Keshan disease is overlapping in northern China. Because there is a very strong spatial correlation between selenium deficiency and Keshan disease, some authors claim the same relationship exist between selenium deficiency and KBD (Allander, 1994 Yang et al., 1988). Selenium levels in food, and also in blood and hair samples, from subjects living in areas where KBD is endemic are systematically lower than in those from nonendemic areas (Wu and Xu, 1987). Clinical trials of oral selenite—vitamin E or sodium selenite alone have been reported as an effective cure for KBD (Yang et al., 1988), but these early studies have not been confirmed to date. 

Dietary intakes of many essential trace elements are being determined by NAA, and results may serve as a basis for improved recommendations of safe and adequate daily average intakes of these elements. As a next step, possibly deficient or toxic intakes, the influence of the environment on dietary intake, correlations with tissue concentrations and clinical symptoms, and so forth may be investigated. A special example of such studies is the correlation of low dietary intakes of selenium with a particular syndrome known as Keshan disease in China. 

Selenium deficiency in animals is manifested by hepatic necrosis and a set of symptoms called white muscle disease. Very serious selenium deficiency in humans has been reported in China, in the Keshan region, where there is very low selenium content in the... 

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