The Calcium Balance of Adult Human Subjects on High- and Low-Fat (Butter) Diets

Abstract
Calcium metabolism studies have been reported on 13 adult men, ranging in age from 19 to 44 years, involving 50 experimental periods of 12 to 20 days' duration. The main purpose of the investigation was to study the effect of variable dietary levels of milk fat, from 1 to 32% on the dry matter basis, on the utilization of dietary calcium, an average of 47% of which was derived from milk. For the type of dietary fat studied and the range of intake emplyed, no effect on calcium metabolism was noted, either in the amount retained or in the proportion of excreted calcium found in the feces. On pooling all of the data together, expressed in milligrams of calcium per day per kilogram of body weight, it was found that, under the conditions imposed, the regression of calcium balance (y) on calcium intake (x) is represented by the equation: y = -3.72 + 0.502 x. This equation implies an average calcium utilization of 50.2 ± 6.2%, a requirement of 7.40 mg of calcium per kilogram body weight per day for calcium equilibrium, and an endogenous output of calcium by adult men of 3.72 mg per kilogram of body weight daily.