Supplementary Material for: Effects of Sulfate-Rich Mineral Water on Functional Constipation: A Double-Blind, Randomized, Placebo-Controlled Study

Background: Magnesium sulfate has a long tradition as a laxative. It osmotically prevents water absorption in the large bowel and thus leads to an acceleration of the intestinal transit and better stool consistency. We wanted to investigate the efficacy of a carbonated calcium/magnesium sulfate-rich natural mineral water in subjects with functional constipation (FC). Patients and Methods: In this double-blind, randomized, placebo-controlled study, subjects with FC (Rome III criteria) received 1 l/day (4 × 250 ml) of mineral water (Ensinger Schiller Quelle) or carbonated tap water (placebo) for 6 weeks. The primary endpoint was the change in the frequency of bowel movements per week between baseline and visit 4 (after 6 weeks). The prespecified main secondary endpoint was the change in the frequency of bowel movements per week between baseline and visit 3 (after 3 weeks). Results: Efficacy was analyzed in 100 subjects (intention-to-treat). After 6 weeks of treatment there was no statistical difference between the groups (p = 0.163). However, statistical significance was reached after 3 weeks, with an increase in the frequency of bowel movements per week of 2.02 ± 2.22 for the mineral water group compared to 0.88 ± 1.67 for the placebo group (p = 0.005). Conclusions: A 3-week treatment with 1 l/ day of the sulfate-rich mineral water improved the frequency of bowel movements in subjects with FC compared with tap water; however, the difference was no longer significant after 6 weeks. Further evaluation in rigorously designed clinical studies will be necessary to validate the impact of sulfate-rich natural mineral water on FC.