Growth as Affected by Zinc and Protein Nutrition

Abstract

Evidence has been presented that a relationship exists between zinc and the utilization of phytate containing plant-seed proteins and that when properly supplemented with zinc these proteins were equal in quality to animal proteins. Little improvement in growth was obtained from rats fed levels of soybean protein above 12%, provided zinc was supplemented. Even at deficient levels of dietary protein (4 and 8%) animals survived for at least 10 weeks provided the diets were adequately supplemented with zinc; however, 75% of the rats died in an average of 43 days at these levels of protein without zinc supplementation. Organ dry weight was shown to be decreased very markedly in zinc-deficient animals. Activities of certain zinc-dependent enzymes were found to be decreased in sensitive tissues of zinc-deficient rats. The validity of expressing zinc per unit of dry weight or enzyme activity per unit of protein was questioned and discussed. The ce:roles of zinc in the pathogenesis of kwashiorkor was discussed. It is likely that zinc supplementation of cereal diets, consumed by large segments of human population in many areas of the world, may improve growth and well being.