Experimental Zinc Deficiency in Humans

Abstract

The effects of a mild Zn-deficient state in humans were studied. Four male volunteers received restricted Zn intake for several weeks under strict metabolic conditions. As a result of dietary Zn restriction, a decrease in Zn concentration of plasma, erythrocytes, leukocytes and urine was observed. Changes in the activities of Zn-dependent enzymes in the plasma such as alkaline phosphatase and RNase were also related to the dietary Zn status. An adverse effect of Zn restriction on total protein, total collagen, RNA and the activity of deoxythymidine kinase (a Zn-dependent enzyme) in the sponge connective tissue of the 2 volunteers in whom this test was done was noted. During the Zn restriction period, the ammonia level in the plasma was elevated. Weight loss occurred in all subjects as a result of dietary Zn restriction. Inasmuch as the Zn-deficient state was mild, this study provides a basis for developing diagnostic criteria for Zn deficiency in humans.