Clinical trial:: multispecies probiotic supplementation alleviates the symptoms of irritable bowel syndrome and stabilizes intestinal microbiota

Background Irritable bowel syndrome is the most common diagnosis in gastroenterology. Trials suggest certain probiotics to be beneficial. Aim To investigate the effects of multispecies probiotic supplementation (Lactobacillus rhamnosus GG, L. rhamnosus Lc705, Propionibacterium freudenreichii ssp. shermanii JS and Bifidobacterium animalis ssp. lactis Bb 12) on abdominal symptoms, quality of life, intestinal microbiota and inflammatory markers in irritable bowel syndrome. Methods Eighty-six irritable bowel syndrome patients (Rome 11 criteria) participated in this randomized, placebo-controlled 5-month intervention. Patients were randomized to receive daily either multispecies probiotic supplementation or placebo. Irritable bowel syndrome symptoms, quality of life, microarray-based intestinal microbiota stability (n = 20), serum cytokines and sensitive C-reactive protein were monitored. Results The composite irritable bowel syndrome score had at 5 months decreased 14 points (95% CI: -19 to -9) from baseline with the multispecies probiotic vs. three points (95% CI: -8 to 1) with placebo (P = 0.0083). Especially, distension and abdominal pain were affected. A stabilization of the microbiota was observed, as the microbiota similarity index increased with the probiotic supplementation (1.9 +/- 3.1), while it decreased with placebo (-2.9 +/- 1.7). No differences were seen in C-reactive protein. Conclusions This multispecies probiotic seems to be an effective and safe option to alleviate symptoms of irritable bowel syndrome, and to stabilize the intestinal microbiota.