Efficacy and Safety of a Natural Mineral Water Rich in Magnesium and Sulphate for Bowel Function: A Double-Blind, Randomized, Placebo-Controlled Study

Eur J Nutr. 2017 Mar;56(2):491-499. doi: 10.1007/s00394-015-1094-8. Epub 2015 Nov 18.


Purpose: The present placebo-controlled, double-blind, randomized trial aimed to investigate whether a natural mineral water rich in magnesium sulphate and sodium sulphate (Donat Mg) may help to improve bowel function.

Methods: A total of 106 otherwise healthy subjects with functional constipation were randomly assigned to consume 300 or 500 mL of a natural mineral water as compared to placebo water, over a course of 6 weeks. The 300-mL arms were terminated due to the results of a planned interim analysis. Subjects documented the complete spontaneous bowel movements, spontaneous and overall bowel movements/week, stool consistency, gastrointestinal symptoms and general well-being in a diary. Change in the number of complete spontaneous bowel movements was defined as the primary outcome.

Results: For the 75 subjects in the 500-mL arms, the change in the number of complete spontaneous bowel movements per week tended to be higher in the active group when compared to placebo after 6 weeks (T2 = 1.8; p value = 0.036; one-sided). The mean number of spontaneous bowel movements significantly increased over the course of the study, with significant differences between study arms considering the whole study time (F test = 4.743; p time × group = 0.010, 2-sided). Stool consistency of spontaneous bowel movements (p < 0.001) and the subjectively perceived symptoms concerning constipation (p = 0.005) improved significantly with the natural mineral water as compared to placebo.

Conclusions: The daily consumption of a natural mineral water rich in magnesium sulphate and sodium sulphate improved bowel movement frequency and stool consistency in subjects with functional constipation. Moreover, the subjects' health-related quality of life improved.

Clinical trial registration: EudraCT No 2012-005130-11.

Keywords: Bowel function; Clinical trial; Natural mineral water; Stool frequency and consistency.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Constipation / drug therapy*
  • Constipation / epidemiology
  • Diet
  • Double-Blind Method
  • Feces
  • Female
  • Germany / epidemiology
  • Health Promotion
  • Humans
  • Magnesium Sulfate / administration & dosage*
  • Male
  • Middle Aged
  • Mineral Waters*
  • Placebos
  • Quality of Life
  • Sulfates / administration & dosage*
  • Treatment Outcome


  • Mineral Waters
  • Placebos
  • Sulfates
  • sodium sulfate
  • Magnesium Sulfate