Zinc deficiency

Although it has been known for more than six decades that zinc is essential for the growth of micro-organisms, plants, and animals, until 1961 it was believed that zinc deficiency in humans could never occur. It is now clear that nutritional deficiency of zinc is widely prevalent and its morbidities are severe. This article describes the history of the study of zinc deficiency from a single case report in 1961 to its current state. In 1958, a 21 year old male patient in the Iranian city of Shiraz presented with dwarfism, hypogonadism, hepatosplenomegaly, rough and dry skin, mental lethargy, geophagia, and iron deficiency anaemia.1 This patient had an unusual diet. His intake of animal protein was negligible, and he ate only unleavened bread. In addition, he consumed 0.5 kg of clay daily. His total intake of calories and protein (cereal) was adequate, and except for iron deficiency no other deficiency in micronutrients was documented consistently. In the following three months 10 more patients with a similar illness were seen in the same hospital. The growth retardation and testicular hypofunction in all these patients could not be explained on the basis of iron deficiency—these manifestations are not observed even in iron deficient animals. In animals, among the transitional elements known to have adverse effects …