Effect of Level of Protein Intake on Urinary and Fecal Calcium and Calcium Retention of Young Adult Males

Abstract

When calcium and phosphorus intakes were maintained constant at 1400 mg daily, increasing the protein intake of 18-to-20-year-old males from 48 to 141 g daily caused a highly significant increase in urinary calcium, the mean daily values being 175 and 338 mg, respectively. The apparent absorption of calcium was higher by 69 mg daily when the high protein diet was fed, although this effect was not statistically significant. The effect of protein intake on calcium retention approached significance (P < 0.10); the mean daily calcium balance was 10 and -84 mg, respectively, on the low and high protein intake. Protein intake had no effect on serum calcium.