Effect of a high-protein, high-salt diet on calcium and bone metabolism in postmenopausal women stratified by hormone replacement therapy use

The objective of this study was to investigate the influence of a high-sodium, high-protein diet on bone metabolism in postmenopausal women (aged 49–60 y) stratified by hormone replacement therapy (HRT) use. In a crossover trial, 18 women (n=8 HRT users (+HRT) and n=10 nonusers (−HRT)) were randomly assigned to a diet high in protein (90 g/day) and sodium (180 mmol/day) (calciuric diet) or a diet moderate in protein (70 g/day) and low in sodium (65 mmol/day) for 4 weeks followed by crossover to alternative dietary regimen for a further 4 weeks. The calciuric diet significantly (P<0.05) increased urinary sodium, calcium and nitrogen in both groups. While the calciuric diet increased urinary N-telopeptide crosslinks of collagen (by ∼25%, P=0.003) in the −HRT group, it had no effect in the +HRT group. It appears that postmenopausal HRT use attenuates the increase in a marker of bone resorption associated with a calciuric diet.