POTASSIUM BICARBONATE REDUCES HIGH PROTEIN-INDUCED HYPERCALCIURIA IN ADULT MEN

The effect of adding sodium bicarbonate (NaHCO3) and potassium bicarbonate (KHCO3) on high protein-induced hypercalciuria was evaluated in eight healthy male subjects. Subjects were acclimated to high protein and then received in random order, each of the following supplements for four-day periods: 60 g protein (HP), 60 g protein + 90 mmol NaHCO3 (HP+Na), and 60 g protein + 90 mmol KHCO3 (HP+K). Subjects were then given a moderate protein (MP) diet. Subjects provided a 24-hour urine sample on Day 3 and Day 4, and a fasting urine and blood sample on Day 5, of each period. Day 3 and Day 4 calcium excretions were increased during the HP treatment as compared with the MP treatment. During the HP+K treatment, Day 3 and 4 calcium excretions were greatly reduced relative to the HP treatment. In contrast, during the HP+Na treatment, calcium excretion was reduced relative to the HP treatment on Day 3, but not on Day 4. Serum calcium was significantly increased during the HP+K relative to the MP treatment. This study suggests that KHCO3, but not NaHCO3, consistently reduces high protein-induced hypercalciuria to levels seen during ingestion of a moderate protein diet.