The Relation of Calcium and Phosphorus in the Diet to the Absorption of These Elements From the Intestine

Abstract

The problem of absorption from the intestine has taken on a new significance since it has been appreciated that the failure of calcification in rickets is coincident with and apparently dependent on the absorption of minerals. The experiments of Schabad,1 Schloss 2 and others, including us,3 have shown that active rickets is associated with defective absorption of calcium and phosphorus, and that as the disease heals, large quantities of these elements are retained. Moreover, it seems clear that the absorption of these elements can be increased in at least two ways: (1) by the administration of a factor contained in certain animal fats, of which cod liver oil is the best example; and (2) by the use of ultraviolet rays. Both of these measures are effective, even though the quantity of calcium and phosphorus supplied varies greatly. It has been supposed that these substances act by altering in some way the permeability of the intestinal wall toward these particular elements.Although cod liver oil and ultraviolet rays are the methods by which the absorption of these elements has been effected experimentally, still there are other factors which may presumably influence the process, such as the concentration of calcium and phosphorus supplied in the diet, the reaction of the intestinal contents, variations in the concentration of other salts, changes in temperature, etc. It would seem that considerable light

Studies of Calcium and Phosphorus Metabolism

“…Injection of phosphate in dogs was found by Greenwald and Gross (20) to cause an increased excretion of calcium which persisted for several days. Ingestion of excess phosphorus in children has also been found to result in an increased loss of calcium in the feces (21).…”