LAUSR

INTRODUCTION Kidney stone disease (KSD) is a highly prevalent disease worldwide. As water intake and its mineral content influence stone formation and recurrence, patients and physicians must be aware of the mineral content of drinkable water. We analysed commercial bottled still water within Europe to assess the variation in the mineral composition across different manufacturers and countries. METHODS Data on the mineral composition of bottled still water regarding bicarbonate, calcium, magnesium, potassium, sodium and sulphate concentration (mg/L) were collected from ten European countries. To collect the data, the two main supermarket chains in each participating country were either visited to check for the ingredient label on bottles or the online shop was consulted through the website of the supermarket in question. Descriptive statistics like simple boxplots were used to illustrate the variation in mineral content. RESULTS 182 different commercial water brands were analysed. Up to a fivefold variation in average concentrations per mineral between countries was observed. For calcium, a wide distribution was found in France and Switzerland compared to other countries with calcium levels ranging from 10.5 mg/L to 565 mg/L and 8.4 mg/L to 579 mg/L respectively. By consuming two litres of water with such high calcium levels, the daily reference intake for calcium is already achieved. CONCLUSIONS The mineral content of bottled still water across Europe varies greatly. For patients with KSD it is important to be aware of the mineral content of the water they drink as it might influence stone recurrence rates and necessitate alterations of their diet.