Discovery and importance of zinc in human nutrition.

The present explosion in knowledge of zinc has been the result of several factors, the major ones being the recognition of the important role of zinc in human health and diseases, its vital functions in biochemical reactions, and the technological advances that make it feasible to quantitate this essential trace element in biological fluids. Deficiency of zinc in humans due to nutritional factors and several disease states has now been recognized. The high phytate content of cereal proteins is known to decrease the availability of zinc; thus, the prevalence of zinc deficiency is likely to be high in a population consuming large quantities of proteins. Alcoholism, malabsorption, sickle cell anemia, chronic renal disease, and chronically debilitating diseases are now known to be predisposing factors for zinc deficiency. A severe deficiency of zinc such as that seen in patients with acrodermatitis enteropathica may be life-threatening. A spectrum of clinical manifestations ranging from mild to severe degrees has now been recognized in human zinc deficiency states. Zinc appears to be involved in many biological functions including DNA synthesis. Roles for zinc in enzymatic functions, cell membranes, and immunity are now well established.