Immaturity of the Organism as a Factor Determining the Favorable Influence of Lactose on the Utilization of Calcium and Phosphorus

Abstract

The possible influence of the presence of lactose in the diet on the utilization of calcium and phosphorus was studied by performing balance experiments in two young dogs and one mature animal. The ratios and the amounts of these two elements were carefully controlled. Likewise the effect of the phospho-protein casein was compared with that of egg albumen. The data obtained from the young animals indicated very definitely that the presence of lactose in the diet favorably influences the utilization of calcium and phosphorus; no such result was obtained with the mature dog, however. Attempts were made by experiments on rats, using Bergeim's technique, to determine whether this favorable action of lactose is due to increased absorption from or diminished excretion into the intestine. It appears that the use of a low-calcium diet in tracing the absorption of this element is of practically no value because of the quantities of lime thrown into the alimentary tract by the digestive secretions. The data obtained from rats showed too great variation to be judged as entirely satisfactory. Nevertheless, they very definitely confirmed the dog experiments indicating that ‘degree of immaturity’ plays a role in determining the effect of lactose on the utilization of calcium by a given organism. These experiments on rats support, but do not prove, the view that lactose acts to diminish the excretion of calcium into the intestine.