Higher calcium urinary loss induced by a calcium sulphate-rich mineral water intake than by milk in young women

Abstract

It is well known that the intestinal availability of Ca from Ca-rich mineral waters is equivalent to that of milk Ca. However, the effect of associated anions on Ca urinary loss needs to be addressed. The aim of the current study was to compare, under ordinary conditions of consumption, milk and a SO 4 -rich mineral water as the Ca provider in a large number of subjects consuming the same quantity of Ca from the two sources in a crossover study lasting for an extended period. Thirty-seven healthy women completed a 12-week protocol, divided into four periods of 3 weeks (W). In the first (W1-3) and third (W6 -9) periods, dietary Ca intake was restricted to 600 mg/d. In the second (W4 -6) and final (W10-12) periods, either 400 ml/d medium-fat milk or 1 litre of a Ca-and SO 4 -rich mineral water, each providing about 480 mg Ca/d, was added to the diet in a random manner. Dietary evaluation, blood and urinary measures were performed during the last week (W6 and W12) of each Ca supplementation period. The urinary excretion of Ca was higher (0·5 mmol/d more) with water than with milk (P, 0·001). An examination of all the dietary factors known to influence calciuria suggested that the acidogenic action of SO 4 was responsible for this increased calciuria. Thus, despite an equal Ca intake and assuming an unchanged intestinal absorption, these results suggest that Ca balance is better with milk consumption than with CaSO 4 -rich water.

Nutrition Discussion Forum

“…In our study 11 cited by Brandolini et al 1 , it was shown that 7 % of sulfate from a water containing 1479 mg per litre was incorporated and in urine and stool between 30 and 60 % was in the form of conjugates or bound to organic compounds. There are hundreds of sulfur-containing compounds in the human body 12 and sulfated oligosaccharides have important biological roles, their unique structure contributing to recognition by a receptor 13 .…”

“…I did not intend to revisit the discussion of the publication of Brandolini et al 1 on Ca urinary excretion attributed to the sulfate content of water but in their answers 2 to my comments 3 , they said that 'I accept their experimental results' and that 'I do not contest the difference in calciuria between milk and sulfate-rich water'. I never wrote that I agree with their results and even more with their conclusions but questioned how is it possible to evaluate a 20 mg difference in daily Ca urinary excretion from a study with subjects under uncontrolled dietary intakes, unbalanced experimental study design and without analytical results on acid -base balance and sulfate to support their acidogenic hypothesis of sulfate.…”

Magnesium bioavailability from mineral waters with different mineralization levels in comparison to bread and a supplement

“…Notably, MW 3 was rich in SO 4 2- (1463 mg/l), which is thought to potentially increase urinary volume and therefore decrease Mg bioavailability [34,35]. To our knowledge, no study has investigated the potential influence of SO 4 2- in food on the bioavailability of Mg in humans.…”

Outcome of a public consultation on the Draft Scientific Opinion of the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) on Dietary Reference Values for calcium

“…With regard to the comment about calcium sulphate-rich mineral water, the text in Section 2.3.7 of the Scientific Opinion has been amended as follows to clarify the fact that urinary (not faecal) calcium has been measured: "In a crossover study undertaken in 37 healthy women comparing a calcium sulphate-rich mineral water and milk, each providing about 480 mg calcium/day, there were significantly higher levels of calcium in the urine (20 mg/day) during the periods when the calcium sulphate-rich water was consumed (Brandolini et al, 2005). The authors suggest that the acidogenic action of the high sulphate intake may have been responsible for the increased calciuria.…”

“…This point has not been sufficiently discussed in the present report. Lines 759-763: In this cross-over study, both groups consumed the same amount of calcium and the endpoint was urinary calcium but not calcium retention (faeces not collected).Therefore, this lines must be replaced by the next lines : "In a crossover study undertaken in 37 healthy women comparing a calcium sulphate-rich mineral water and milk, each providing about 480 mg Ca per day, there was a significantly higher calciuria (20 mg/d) during the periods when the sulphate-rich water was consumed (Brandolini et al, 2005). The authors suggest that the acidogenic action of the high sulphate intake may have been responsible for the increased calciuria".…”