Effect of Lactobacillus gasseri BNR17 on irritable bowel syndrome: a randomized, double-blind, placebo-controlled, dose-finding trial

Lactobacillus gasseri BNR17 is a strain isolated from human breast milk. The objective of this randomized, double-blind, placebo-controlled, and preliminary dose-finding trial was to find the effective dose and evaluate the effect of Lb. gasseri BNR17 on irritable bowel syndrome (IBS) symptoms. A total of 55 volunteers aged over 20 years with body mass index over 23 kg/m² were randomized to intake a placebo, low-dose (BNR-L, 2 × 10⁸ CFU/day), intermediate-dose (BNR-M, 2 × 10⁹ CFU/day), or high-dose BNR (BNR-H, 2 × 5 × 10⁹ CFU/day) for four weeks. Questionnaire for IBS symptoms scores and Lb. gasseri BNR17 in feces were assessed at the beginning and end of the trial. Among IBS symptoms scores, abdominal pain score was significantly reduced in BNR-H group. Lb. gasseri BNR17 was detected in all intake groups except placebo. In the preliminary study, Lb. gasseri BNR17 was confirmed to have probiotic properties.