Keshan disease is seen in deficiency of -

Ans. is 'a' i.e., Selenium Selenium* Selenium, in the form of selenocysteine, is a component of the enzyme glutathione peroxidase, which serves to protect proteins, cell membranes, lipids, and nucleic acids from oxidant molecules. As such, selenium is being actively studied as a chemopreventive agent against certain cancers, such as prostate cancer.* Selenocysteine is also found in the deiodinase enzymes, which mediate the deiodination of thyroxine to triiodothyronine.* Rich dietary sources of selenium include seafood, muscle meat, and cereals, although the selenium content of cereal is determined by the soil concentration.* Countries with low soil concentrations include parts of Scandinavia, China, and New Zealand.* Keshan disease is an endemic cardiomyopathy found in children and young women residing in regions of China where dietary intake of selenium is low (<20 g/d).* Concomitant deficiencies of iodine and selenium may worsen the clinical manifestations of cretinism.* Chronic ingestion of high amounts of selenium leads to selenosis, characterized by hair and nail brittleness and loss, garlic breath odor, skin rash, myopathy, irritability, and other abnormalities of the nervous system.