The importance of zinc for human health was first documented in 1963. Since 1963, 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 cereal proteins. Alcoholism, malabsorption, sickle cell anemia, chronic renal disease, and chronically debilitating diseases are now known to be predisposing factors for zinc deficiency. A spectrum of clinical manifestations ranging from mild to severe degree have now been recognized in human zinc-deficiency states. Zinc is required for many biological functions including DNA synthesis, cell division, and gene expression. It is required for the activity of many enzymes in biological systems. Recent studies indicate that zinc is needed for cell-mediated immunity
Clinical similarities between patients with sickle cell anemia and zinc-deficient subjects suggested a secondary zinc deficiency in sickle cell anemia. Zinc was assayed in various biological fluids and tissues by atomic absorption spectrophotometry. Zinc in the plasma, erythrocytes, and hair was decreased and urinary zinc excretion was increased in anemia patients as compared to controls. Erythrocyte zinc and daily urinary zinc excretion were inversely correlated in the anemia patients (r = -.63, P < 0.05), suggesting that hyperzincuria may have caused zinc deficiency in these patients. Carbonic anhydrase, a zinc metalloenzyme, correlated significantly with erythrocyte zinc (r = +0.94, P < 0.001). Plasma RNase activity was significantly greater in anemia subjects than in controls. We administered zinc sulfate, 660 mg per day, orally, to seven men and two women with sickle cell anemia. Two 17-year-old males gained 5 cm and 7 cm in height during 49 and 42 weeks of zinc therapy, respectively. All but one patient gained weight (0.5 kg to 4.1 kg). Five of the males showed increased growth of pubic, axillary, facial, and body hair, and in one a leg ulcer healed in six weeks on zinc and in two others some benefit of zinc therapy on healing of ulcers was noted.
