The first to be recognized as an essential part of a metalloenzyme (carbonic anhydrase), zinc is the latest—if not the last trace metal implicated in deficiency disorders. Until recently, it was assumed that the abundant presence of zinc in meat, whole grain, legumes, and seafood would ensure the needed daily minimum of less than 5 mg/day for the synthesis of more than 20 enzymes of which zinc is an essential cofactor. This assumption appears to be illfounded.
Not too long ago, a JAMA editorial (228:1669-1670, 1974) called attention to the reported zinc deficiency, associated with the distorted or diminished taste and smell sensations that may occur in the wake of respiratory infections1 or during the course of viral hepatitis.2 Orally administered zinc alleviated the symptoms.
In a review of the broader ramifications of zinc deficiency, such as some gross disturbances of growth and gonadal development reported from the