71 Central European Journal of Urology ORIGINAL PAPER UROLITHIASIS Variations in the mineral content of bottled ‘carbonated or sparkling’ water across Europe: a comparison of 126 brands across 10 countries Simone J.M. Stoots1, Rob Geraghty2, Guido M. Kamphuis1, Enakshee Jamnadass3, Michaël M.E.L. Henderickx1, Eugenio Ventimiglia4, Olivier Traxer5, Etienne X. Keller6, Vincent De Coninck7, Michele Talso8, Panagiotis Kallidonis9, Esteban Emiliani10, Ewa Bres-Niewada11, Sadaf S. Karim3, Angela Piccirilli10, Athanasios Vagionis9, Bhaskar K. Somani3 1 University of Amsterdam, Amsterdam UMC, Department of Urology, Amsterdam, The Netherlands 2 Freeman Hospital, Department of Urology, Newcastle, United Kingdom 3 University Hospital Southampton NHS Trust, Department of Urology, Southampton, United Kingdom 4 IRCCS Ospedale, Urological Research Institute, Division of Experimental Oncology/Unit of Urology, San Raffaele, Milan, Italy 5 Sorbonne University, GRC#20 Urolithiasis, Paris, France 6 University of Zurich, University Hospital Zurich, Department of Urology, Zurich, Switzerland 7 AZ Klina, Department of Urology, Brasschaat, Belgium 8 ASST Fatebenefratelli-Sacco – Luigi Sacco University Hospital, Department of Urology, Milan, Italy 9 University of Patras, Department of Urology, Patras, Greece 10 Fundació Puigvert, Autonomous University of Barcelona, Department of Urology, Barcelona, Spain 11 Roefler Memorial Hospital, Department of Urology, Pruszków, Poland Citation: Stoots SJM, Geraghty R, Kamphuis GM, et al. Variations in the mineral content of bottled ‘carbonated or sparkling’ water across Europe: a comparison of 126 brands across 10 countries. Cent European J Urol. 2021; 74: 71-75. Article history Introduction Kidney stone disease is a common disease with high recurrence rates. Sufficient intake Submitted: Nov. 16, 2020 of water is the cornerstone in primary prevention of stone disease. However, the mineral composition Accepted: Jan. 25, 2021 of water can affect urinary minerals and influence stone formation. The aim of this study is to assess the Published online: Feb. 19, 2021 variation in the mineral composition of bottled sparkling or carbonated drinking water across Europe. Material and methods The two largest supermarket chains in each participating country were visited to obtain data on mineral composition regarding bicarbonate, calcium, magnesium, potassium, sodium and sulphates of sparkling or carbonated waters by reading the ingredient labels on the bottles supplied by the manufacturers. Alternatively, the web-shops of these supermarkets were consulted. Results In total, 126 sparkling water brands across ten European countries were analysed regarding mineral composition. The median concentrations per mineral varied greatly. The greatest variation Corresponding author Simone J.M. Stoots in median mineral content was found for sodium and sulphates with levels ranging from 3.1 mg/l University of Amsterdam to 63.0 mg/l and 6.0 mg/l to 263.0 mg/l respectively. A wide distribution of calcium content was found Amsterdam UMC in Switzerland, with calcium levels reaching up to 581.6 mg/l. Department of Urology Conclusions This study confirms that the mineral composition of sparkling or carbonated water varies 9 Meibergdreef greatly across Europe. Patients with kidney stone disease should be aware that the mineral content 1105 AZ Amsterdam, The Netherlands of water may influence stone formation and be mindful of the great variation that exists between differ- phone: +31 647 944 916 ent water brands. Mineral water can be a source of potential promotors or inhibitors of stone formation simone.stoots@gmail.com and patients and urologists need to be mindful of this. Key Words: urolithiasis ‹› kidney stone disease ‹› mineral content ‹› mineral composition ‹› sparkling water Cent European J Urol. 2021; 74: 71-75 doi: 10.5173/ceju.2021.0331.R1 72 Central European Journal of Urology INTRODUCTION or carbonated’ water to assess variation in mineral compositions across different manufacturers and Kidney stone disease (KSD) has a life time preva- countries within Europe. lence rate of up to 14% in Europe with a recurrence rate of 50% in 5–10 years [1, 2]. It is characterised by MATERIAL AND METHODS stone formation in the urinary tract and while there has been a lot of research in stone treatment with This study aims to provide a complete overview several treatment options available, comparatively of the mineral composition of sparkling or carbon- little research has been done for primary stone pre- ated bottled drinking water across Europe. It is vention. The incidence of kidney stone disease has a multinational study that was conducted in ten Eu- been rising due to multiple factors including more ropean countries including Belgium, France, Ger- imaging, warm weather, a rise in obesity and meta- many, Greece, Italy, the Netherlands, Poland, Spain, bolic syndrome [3, 4, 5]. Apart from the morbidity Switzerland and the United Kingdom. In each coun- and health impact, it also affects patients’ quality try, the two largest supermarket chains were visited of life and is a costly disease comparable to the com- to obtain raw data on the mineral composition bined cost of prostate and bladder cancer [6, 7]. of sparkling or carbonated waters by reading the in- It is generally accepted that sufficient fluid intake gredient labels on the bottles supplied by the manu- has a role in the primary prevention of stone disease, factures. Alternatively, the web-shops of these super- with the aim of achieving a urine output of two li- markets were consulted. The minerals studied were tres or more per day [8]. This leads to an increase bicarbonate, calcium, magnesium, potassium, so- in urine output and resultant dilution of lithogenic dium and sulphates. Data collection was performed factors such as oxalate, calcium and uric acid, con- from October 2019 – December 2019 by an individual sequently reducing crystallization of calcium salts. from every country included in the study. With increased diuresis, there is less stagnation of urine which can serve as a mechanical factor Statistical analysis in stone formation [9, 10]. A high water intake and hydration seems to be the The software Statistical Package for Social Sciences cornerstone in the prevention of kidney stone dis- (SPSS), version 26 (IBM CORP., Armonk, New York, ease. The mineral composition of water from dif- USA) was used to analyse the data. First, the data ferent sources can also affect urinary minerals and were checked for normality. All data were treated influence stone formation. Enormous variation has as non-parametric data as they were not normally been shown in tap water and different brands of min- distributed. eral water [11, 12, 13]. While ‘still’ water is common- For optimal graphic representation of the data, sim- ly consumed, ‘sparkling’ water infused with carbon ple box plots were used. Furthermore, by using box dioxide gas under pressure is also preferred by some plots the distributional features of the data could as drinking water or as a mixer with other drinks. be examined. Outliers and extremes values are dis- The aim of this study was to analyse ‘sparkling played as circles and asterisks respectively. Table 1. Mineral composition (mg/l) of bottled sparkling or carbonated water by country (median [IQR]) Mineral composition (mg/l) Country Bicarbonate Calcium Magnesium Potassium Sodium Sulphates Belgium 220.0 [180.0–317.0] 56.0 [13.5–151.5] 7.0 [2.0–18.0] 2.0 [1.0–5.0] 10.6 [9.0–33.3] 19.0 [8.0–33.0] France 1175.0 [710.0–1837.0] 51.5 [90.0–185.0] 15.0 [8.0–49.0] 3.0 [11.0–52.0] 10.0 [7.5–381.0] 30.0 [20.0–59.0] Germany 253.0 [189.0–349.0] 67.5 [47.0–142.0] 23.0 [5.0–42.0] 2.0 [1.0–4.0] 15.8 [13.3–29.9] 36.0 [9.0–162.0] Greece 344.2 [274.0–781.0] 87.2 [59.3–188.0] 24.0 [3.0–53.0] 0.0 [0.0–0.0] 6.0 [4.4–20.0] 11.0 [5.0–12.0] Italy 212.6 [57.4–930.0] 43.5 [9.1–164.0] 13.0 [2.0–25.0] 1.0 [1.0–2.0] 3.1 [1.5–6.0] 6.0 [4.0–18.0] Netherlands 190.0 [170.0–360.0] 68.5 [40.9–101.5] 7.0 [3.0–18.0] 2.0 [1.0–3.0] 10.3 [6.0–30.6] 29.0 [9.0–37.0] Poland 1260.0 [335.6–1550.0] 80.9 [97.8–301.0] 52.0 [13.0–153.0] 7.0 [2.0–49.0] 63.0 [4.6–118.0] 29.0 [27.0–32.0] Spain 287.0 [215.5–1935.5] 55.0 [32.0–86.8] 8.0 [4.0–31.0] 9.0 [3.0–49.0] 38.8 [7.6–835.5] 11.0 [7.0–48.0] Switzerland 273.5 [243.5–360.5] 91.0 [97.7–330.0] 36.0 [22.0–52.0] 2.0 [1.0–3.0] 5.2 [4.0–7.0] 263.0 [55.0–85.0] United Kingdom 240.0 [215.0–245.0] 56.0 [55.0–104.0] 18.0 [10.0–19.0] 2.0 [1.0–2.0] 11.5 [7.5–24.0] 13.0 [9.0–28.0] 73 Central European Journal of Urology Figure 1. Simple boxplots of the mineral composition (mg/l) of bottled sparkling or carbonated water per mineral by country. RESULTS expressed as median [IQR]. The median concen- trations per mineral varied greatly within Europe. In total, 126 different commercial water brands Bicarbonate concentration ranged from 212.6 mg/l for sparkling or carbonated bottled drinking water in Italy to 1260.0 mg/l in Poland. Calcium concentra- across ten European countries were analysed regard- tion ranged from 43.5 mg/l to 91.0 mg/l. Magnesium ing the mineral composition. The following commer- concentration ranged from 7.0 mg/l in Belgium and cial water brands for sparkling or carbonated wa- the Netherlands to 52.0 mg/l in Poland. The medi- ter were sold in up to eight different countries: Bar an mineral concentration across Europe shows the le Duc, Chaudfontaine, Gerolsteiner Medium, Per- greatest variation for sodium and sulphates with lev- rier, San Benedetto, San Pellegrino, Sourcy and Spa els ranging from 3.1 mg/l to 63.0 mg/l and 6.0 mg/l Intense. to 263.0 mg/l respectively. Table 1 shows the mineral composition of sparkling The lowest median concentration per mineral were or carbonated bottled drinking water across Europe found in Italy, except for magnesium and potassium. 74 Central European Journal of Urology Sparkling or carbonated waters available in Poland vised a normal-calcium diet, which is 1000–1200 mg showed the highest median concentrations regard- of calcium daily [14, 15]. By drinking 2.5 L of Melt- ing bicarbonate, magnesium and sodium. inger sparkling water, with a calcium content The distributional features of the mineral composi- of 581.6 mg/l, the daily intake of calcium is already tion of sparkling or carbonated bottled waters across exceeded. In other words, although water helps to Europe per mineral are shown in Figure 1. The box- prevent kidney stone disease, kidney stone patients plots visualize a great variability in mineral compo- must be aware of this level of calcium in the water sition per mineral. Calcium and sulphates content and balance calcium rich foods like cheese, milk of sparkling or carbonated waters sold in Switzer- or yoghurt, which can also be a high source of cal- land show a wide distribution compared to the other cium intake. participating countries. The range for calcium con- However, calcium is not the only mineral affecting tent in Switzerland reaches 573.2. For sulphates, stone formation. Excessive intake of sodium also pro- with a minimum of 3.8 and a maximum of 1445.0, motes kidney stone disease as it increases urinary cal- the range was 1441.2. Potassium levels varied great- cium excretion in patients suffering from idiopathic ly in France, from 0 mg/l to 110 mg/l. calcium stone disease and hypercalciuria [16]. For these patients, a low-sodium diet is suggested. How- DISCUSSION ever, some of the water included in our study had high sodium levels. Water with a sodium content exceed- This multi-national study, conducted in ten Euro- ing 1000 mg/l were San Narciso (1080.0 mg/l), Vichy pean countries including Belgium, France, Germany, Catalan (1097.0 mg/l) and Malavella (1115.0 mg/l) Greece, Italy, the Netherlands, Poland, Spain, Swit- all available in Spain, and Saint-Yorre (1708.0 mg/l) zerland and the United Kingdom, demonstrates the which is sold in France. wide variation in the mineral content of bottled spar- Although excessive amounts of calcium and sodium kling or carbonated water from 126 brands which might negatively influence stone formation, other are commercially available across Europe. The aver- minerals might prevent stone recurrence in kidney age bicarbonate content across Europe varies with stone disease. Water with high bicarbonate con- a factor of 5.9. What is more, the average sulphate tent, for example, might be beneficial regarding kid- concentration varies with a factor of 43.8. ney stone formation. A study performed by Siener It is noteworthy that the calcium content of spar- et al., which evaluated the effect of mineral water kling or carbonated waters sold in Switzerland, var- rich in calcium, magnesium and bicarbonate, sug- ied enormously. Here, the calcium content varied gested that hypercalciuria as an effect of high cal- from 8.4 mg/l (San Clemente Frizzante) to 581.6 mg/l cium content of mineral water is counterbalanced (Meltinger). Of all water brands included in our study, by its high levels of bicarbonate and magnesium sparkling water from Meltinger contained the high- which results in an increase in citrate excretion [17]. est calcium content. In fact, 75% of the water with Furthermore, bicarbonate intake creates alkalinity a calcium content exceeding 400 mg/l originated from resulting in a higher urinary pH. If 1.5 L of water Switzerland. These included Adelbodner Mineral is drunk with a bicarbonate content of 2673 mg/l, (579.0 mg/l), Farmer Mineral Rot (564.0 mg/l), Adello it leads to metaphylactic levels of it as shown by Mineral (530.0 mg/l), Eptinger Pricklnd (510.0 mg/l) a clinical study by Karagülle et al., decreasing the risk and Valser (435.0 mg/l). Carolinen Classic and Caro- of uric acid precipitation. In addition, mineral water linen Medium, which are sold in Germany contained with high bicarbonate content promotes excretion 421.0 mg/l of calcium. The lowest calcium concen- of inhibitory elements like magnesium and citrate and tration of all the waters included in our study was might therefore decrease calcium oxalate stone for- 2.9 mg/l from Sant’ Anna, Italy. This means that the mation [18]. Our study includes one water with such overall calcium content across Europe could be 200 high bicarbonate levels: Saint Yorre (4368.0 mg/l) times as high in one country compared to another. sold in France. However, this type of sparkling water Several studies, which are recently evaluated in also had the highest sodium content of all included a systematic review by Sulaiman et al., show that water brands across Europe, suggesting that spar- drinking 2 L of water with high calcium content, kling waters with solely a high bicarbonate content that is more than 232 mg/l, results in hypercalci- are not commercially available. uria, a risk factor for calcium stone formation [11]. A previous study has assessed the variation in min- Therefore, for patients with KSD, it is important eral content of bottled ‘still’ water, however this is to realize the extent to which calcium levels of drink- the first study that assessed the variation in the min- ing water vary as high calcium intake may influ- eral content of bottled sparkling or carbonated wa- ence stone formation. Nowadays, patients are ad- ter across Europe [12]. Our study does however have 75 Central European Journal of Urology some limitations. In Europe, tap water is mostly ment of kidney stones. However, due to the complex of adequate quality, so it would be interesting to anal- and multifactorial aetiology of stone formation, it re- yse its mineral composition as some people might mains difficult to determine to what extend the min- not be able to afford bottled water, being relatively eral content of water affects stone formation. expensive compared to tap water. On the contrary, the consumption of bottled water is increasing in the CONCLUSIONS European Union [19]. We also did not look at ‘min- eral water’ composition which is also consumed by This study confirms that the mineral composition some patients. of sparkling or carbonated water varies greatly In addition to this, our study only included bottled across Europe. Patients with kidney stone disease waters that are sold in the two largest supermarkets should be aware that the mineral content of wa- chain per country. Further research must be done ter may influence stone formation and be mindful to provide a complete overview of the mineral con- of the great variation that exists between differ- tent of sparkling or carbonated waters that are avail- ent water brands. Mineral water can be a source able all over Europe. A worldwide study evaluating of potential promotor or inhibitor of stone forma- the mineral content of bottled drinking water is also tion and patients and urologists need to be mindful suggested to properly advise kidney stone patients of this. regarding water intake. Over time, several studies have been conducted to Conflicts of interest evaluate the effect of mineral water on the develop- The authors declare no conflicts of interest. References 1. Rukin NJ, Siddiqui ZA, Chedgy ECP, a mean follow-up of 19 years. 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