Calcium in mineral water can effectively suppress parathyroid function and bone resorption

Abstract

The present study was designed to measure the effects, on parathyroid function and bone metabolism, of ingestion of high-calcium mineral water and of a calcium salt bringing the same dose (600 mg) of calcium as a reference. Fifteen healthy young men (mean ± SD age : 23.3 ± 1.2) ingested, during 3 different experimental periods chosen at random, a) high-calcium mineral water (596 mg/L), b) low-calcium mineral water as a control assay, c) one bag of tricalcium phosphate powder containing 600 mg of calcium. Serum concentrations of ionized calcium (iCa), intact parathyroid hormone (iPTH) and of a biochemical marker of bone resorption, type I collagen cross-linked C telopeptide (CTX), were measured before 08.00 and every hour from 09.00 to 17.00. Serum iCa concentrations were significantly ( P < 0.0001) higher and serum iPTH concentrations were significantly ( P < 0.01) lower after oral intake of both high-calcium water and tricalcium phosphate than in control period. Serum concentrations of CTX were significantly lower after either high-calcium water ( P < 0.0001) or tricalcium phosphate ( P = 0.011) than in the control period and a statistically significant difference ( P < 0.05) using Bonferroni t test between the effects of high-calcium mineral water and of tricalcium phosphate was observed from 14.00 to 17.00. The same total amount of calcium (# 600 mg) from one liter of high-calcium mineral water, divided into three intakes, at 3 hours intervals, resulted in a more prolonged suppression of serum CTX, than from the ingestion of a calcium salt.