A comparison of the effects of feeding sulfur amino acids and protein on urine calcium in man.

It has been suggested that the sulfur amino acids in protein are responsible for the calciuria observed after protein ingestion. This hypothesis was tested by feeding meals containing either 15 g protein (control), 45 g protein (high protein), or 15 g protein plus sulfur amino acids equivalent to those in the high protein diet. Compared to the control, the high protein diet caused an increase in urinary calcium and sulfate and a decrease in the renal reabsorption of calcium. In contrast, the sulfur amino acid supplement had no effect on calcium excretion or reabsorption. Net acid excretion was unaffected by dietary treatment.