Clinical and biochemical manifestation zinc deficiency in human subjects.

During the past two decades, essentiality of zinc for man has been established. Deficiency of zinc in man attributable to nutritional factors and several diseased states has been recognized. High phytate content of cereal proteins decreases availability of zinc, thus the prevalence of zinc deficiency is likely to be high in the population subsisting on cereal proteins mainly. Zinc deficiency has been noted to occur in patients with malabsorption syndrome, chronic renal disease, cirrhosis of the liver, sickle cell disease, AE, and other chronically debilitating diseases. Growth retardation, male hypogonadism, skin changes, poor appetite, mental lethargy and delayed wound healing are some of the manifestations of chronically zinc-deficient human subjects. In severely zinc-deficient patients, dermatological manifestations, diarrhea, alopecia, mental disturbances and intercurrent infections predominate. If untreated, the condition becomes fatal. Zinc deficiency affects testicular functions adversely in man and animals. This effect of zinc is at the end-organ level. It appears that zinc is essential for spermatogenesis. Zinc is involved in many biochemical functions. Several zinc metalloenzymes have been recognized in the past decade. Zinc is required for each step of cell cycle in microorganisms and is essential for DNA synthesis. The effect of zinc on protein synthesis may be attributable to its vital role in nucleic acid metabolism. The activities of many zinc-dependent enzymes have been shown to be affected adversely in zinc-deficient tissues. Zinc atoms in some of the enzyme molecules participate in catalysis and also appear to be essential for maintenance of structure of apoenzymes. Zinc also plays a role in stabilization of biomembrane structure and polynucleotide confirmation.(ABSTRACT TRUNCATED AT 250 WORDS)