Secondary Calcium Phosphate Prevents and Cures Rickets Without Vitamin D. 1. Utilization Studies

Abstract

These studies were undertaken ( 1 ) to demonstrate the capacity of the animal organism to utilize the calcium contained in these compounds as compared with the utilization of calcium from other sources.(2) To compare bone-forming properties of refined "pure" dicalcium phosphate, t unrefined dicalcium phosphate,$ and other calcium compounds. ( 3 ) To determine the availability to the organism of various sources of calcium after their incorporation with alimentary fluids.To determine the relative efficiency of different calcium compounds, feeding experiments were conducted with the albino rat.When calcium is provided not to include phosphorus, i. e., the carbonate or citrate, the retention is seriously interfered with. Whatever phosphorus is supplied as a constituent of the other ingredients of the diet, is not satisfactorily utilized. On the other hand, when the calcium is supplied as calcium phosphate, the phosphorus retention is greatly improved. In spite of this, however,' the efficiency with which the calcium is utilized appears to be more depencl'ent on the form of the calcium phosphate. The average calcium retention observed during the periods of feeding tricalcium phosphate was 30.9%, the retention values observed in the unrefined dicalcium phosphate and refined dicalcium phosphate periods averaged 46.8% and 41.2%, respectively. The superiority of the latter substances to tricalcium phosphate probably is related to their greater availability, i. e., solubility in the digestive fluids.1. The calcium contained in unrefined and refined dicalcium phosphate is utilized much more efficiently than are equivalent quantities of calcium supplied in the form of carbonate or citrate. 2. That this is not due solely to the fact that phosphorus is a limiting factor in these diets is demonstrated by the fact that the calcium of refined dicalcium phosphate is utilized about 70% more efficiently than is the calcium in tricalcium phosphate. 3. Unless adequate quantities of phosphorus, as well as of calcium, are assured, progressive changes take place resulting in the decalcification CoiicZusz'onx t Diealfos,