Metabolic Significance of the Ratio of Calcium to Phosphorus in Foods and Diets

¹ Department of Nutrition and Food Science, Massachusetts Institute of Technology, Cambridge, Massachusetts

The literature indicates that excessive amounts of phosphorus in the diets of animals may interfere with the absorption of minerals and may even cause the development of renal calculi. Most of these results have been obtained in experiments with laboratory animals (rats, mice, dogs, etc.). The extrapolation of these data to human beings should be made with caution. Rickets can be produced in rats by feeding diets which (a) contain no vitamin D, (b) are unusually low in calcium (or phosphorus) content, and (c) contain massive amounts of phosphorus (or calcium). All three conditions are requisite; otherwise rickets will not result.

The Ca/P ratios of habitual diets are of no practical importance in human nutrition. Experiments with rats indicate that renal calculi are less likely to form if the Ca/P ratio of diets is distorted by the addition of phosphates. The calcium and phosphorus contents of the foods and diets of mankind vary greatly. The phosphorus content of the natural diets of human beings is often higher than the phosphate-supplemented cariostatic diets commonly fed to experimental animals in dental caries research.