Randomized double blind placebo-controlled trial of Saccharomyces cerevisiae CNCM I-3856 in irritable bowel syndrome: improvement in abdominal pain and bloating in those with predominant constipation

Background: Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder characterized by recurrent abdominal pain and/or discomfort. Probiotics have been reported to benefit IBS symptoms but the level of benefit remains quite unclear. Objective: This study was designed to assess the benefit of Saccharomyces cerevisiae I-3856 on IBS symptoms. Methods: A randomized, double blind, placebo-controlled trial has been performed in 379 subjects with diagnosed IBS. Subjects were randomly supplemented with the probiotics (1000 mg) or placebo for 12 weeks. Questionnaires (gastrointestinal symptoms, stools, wellbeing, and quality of life) were completed. Primary endpoint was percentage of responders defined as having a 50% decrease in the weekly average intestinal pain/discomfort score'' for at least 4 out of the last 8 weeks of the study. Results: There was no overall benefit of S. cerevisiae I-3856 on IBS symptoms and wellbeing in the study population. Moreover, S. cerevisiae I-3856 was not statistically significant predictor of the responder status of the subjects (p > 0.05). Planned subgroup analyses showed significant effect in the IBS-C subjects: improvement of gastrointestinal symptoms was significantly higher in active group, compared to placebo, on abdominal pain/discomfort and bloating throughout the study and at the end of the supplementation. Conclusions: In this study, S. cerevisiae I-3856 at the dose of 1000 mg per day does not improve intestinal pain and discomfort in general IBS patients. However, it seems to have an effect in the subgroup with constipation which needs further studies to confirm.