Alkaline mineral water lowers bone resorption even in calcium sufficiency: : Alkaline mineral water and bone metabolism

BackgroundDietary acid charge enhances bone loss. Bicarbonate or alkali diet decreases bone resorption in humans. We compared the effect of an alkaline mineral water, rich in bicarbonate, with that of an acid one, rich in calcium only, on bone markers, in young women with a normal calcium intake.MethodsThis study compared water A (per litre: 520 mg Ca, 291 mg HCO3−, 1160 mg SO4−, Potential Renal Acid load (PRAL) + 9.2 mEq) with water B (per litre: 547 mg Ca, 2172 mg HCO3−, 9 mg SO4−, PRAL − 11.2 mEq). 30 female dieticians aged 26.3 yrs (SD 7.3) were randomized into two groups, followed an identical weighed, balanced diet (965 mg Ca) and drank 1.5 l/d of the assigned water. Changes in blood and urine electrolytes, C-telopeptides (CTX), urinary pH and bicarbonate, and serum PTH were measured after 2 and 4 weeks.ResultsThe two groups were not different at baseline, and showed a similar increase in urinary calcium excretion. Urinary pH and bicarbonate excretion increased with water B, but not with water A. PTH (p = 0.022) and S-CTX (p = 0.023) decreased with water B but not with water A.ConclusionIn calcium sufficiency, the acid calcium-rich water had no effect on bone resorption, while the alkaline water rich in bicarbonate led to a significant decrease of PTH and of S-CTX.