The influence of NaCl and KCl on urinary calcium excretion in healthy young women

Abstract

The calciuric effects of NaCl and KCl were compared in 11 healthy young women consuming diets containing 600 mg calcium per day. Each subject participated in three treatment periods: (1) control diet containing 44 mmol Na and 64 mmol K, (2) control diet plus 102 mmol NaCl and (3) control diet plus 104 mmol KCl. Urine was collected during the last two days of each treatment period and analyzed for Ca, Na, K and Cl. The NaCl supplement produced calciuria similar to that reported by other researchers. However, the KCl supplement did not cause calciuria. Subjects receiving the KCl excreted 5.2±0.4 mmol Ca compared to 7.0±0.4 mmol Ca during NaCl supplementation and 5.9±0.6 mmol Ca during the control period. This suggests that the current practice of replacing some NaCl in food processing, or in salt substitutes, with KCl will decrease the amount of sodium consumed by the general population without contributing to calcium excretion.