Branched fat synthesizing Bacillus subtilis improves gastrointestinal symptoms. A phase 1/2A randomized controlled trial

Abstract Background Functional gastrointestinal disorders (FGIDs) are a common, difficult to manage condition. Branched chain fatty acids are emerging as a dietary component that influence gastrointestinal (GI) health. We conducted a double blinded randomized controlled trial of a proprietary strain of deactivated Bacillus subtilis (BG01-4™) that produce branched change fatty acids (BCFA) in the lower GI tract to treat self-reported FGID. Methods Participants (n = 67) completed a four-week intervention of BG01-4™ (n = 34) or placebo (n = 33). The Gastrointestinal Symptom Rating Scale (GSRS) served as the outcome measure, collected prior to, at two-weeks, and at the four-week completion of the intervention. Results At four weeks one of three primary outcomes, constipation in the experimental group, was improved compared to placebo; both other primary outcomes Total GCRS and diarrhoea, were significantly improved in both experimental and placebo groups. The pre-planned secondary outcome indigestion was improved at four weeks compared to entry with trend to significance compared to placebo (p = 0.079). Exploratory analysis revealed clusters for constipation (18% improvement, p < 0.001), indigestion (11% improvement, p = 0.04), and dyspepsia (10% improvement, p = 0.04), were significantly improved in the intervention group compared to the placebo. Conclusions These initial findings suggest that in people with self-reported FGID, BG01-4™ improves specific symptoms of constipation and related GI dysfunction, potentially mediated via synthesis of BCFA. Longer term confirmatory studies for this intervention are warranted. Trial registration: This study was registered prospectively (25/10/2021) at the Australian New Zealand Clinical Trials Registry (ACTRN12621001441808).