The Excretion of Zinc in Health and Disease.

During recent years increasing attention has been directed towards the occurrence of zinc as a normal constituent of animal tissues and fluids (1). Its wide distribution in foodstuffs and particularly its concentration in germ cells-the endosperm of wheat and the yolk of eggs, for example-and constant presence in milk points to a definite utilization. The fact that there is a more or less definite ratio of zinc to calcium in blood in the proportion of 7:100, and that zinc metabolism in animals has been shown to bear some relation to inorganic salt metabolism in general (2), leads to speculation as to the part it plays in the human organism. For this reason it was felt desirable to secure further data regarding the excretion of absorbed zinc under conditions of disease as compared with the normal. It is interesting to note that man ingests in his food practically as much zinc as he does iron. Far the greater part is excreted through the intestine. A small amount, however, is absorbed and excreted through the urine and, as the latter is a better index of absorbed zinc, a series of analyses of urinary zinc under conditions of health and disease was carried out.