POTASSIUM BICARBONATE REDUCES HIGH PROTEIN-INDUCED HYPERCALCIURIA IN ADULT MEN

The effect of adding sodium bicarbonate (NaHCO3) and potassium bicarbo nate (KHCO3) on high protein-induced hypercalciuria was evaluated in e ight healthy male subjects. Subjects were acclimated to high protein a nd then received in random order, each of the following supplements fo r 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 gi ven a moderate protein (MP) diet. Subjects provided a 24-hour urine sa mple 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 du ring the HP treatment as compared with the MP treatment. During the HP +K treatment, Day 3 and 4 calcium excretions were greatly reduced rela tive to the HP treatment. In contrast, during the HP+Na treatment, cal cium excretion was reduced relative to the HP treatment on Day 3, but not on Day 4. Serum calcium was significantly increased during the HPK relative to the MP treatment. This study suggests that KHCO3, but no t NaHCO3, consistently reduces high protein-induced hypercalciuria to levels seen during ingestion of a moderate protein diet.