Effect of a Fermented Soy-Based Probiotic Beverage on Bowel Habit and Faecal Microbiota Composition in Adults with Functional Constipation: A Randomized, Double-Blind, Placebo-Controlled Trial

Abstract

Background: Functional constipation affects roughly one in ten adults; fermented soy beverages have been proposed to improve
bowel habit. Objective: To synthesise trial evidence on soy/dairy probiotic beverages and microbiota outcomes in constipation.
Methods: Narrative review of randomised trials, meta-analyses, and mechanistic studies. Findings: Probiotic beverages increase stool frequency and shorten transit time (SMD 0.40); galacto-oligosaccharides expand faecal Bifidobacterium (10.9% to 23.9%). Synbiotics outperform single agents. Conclusions: Fermented soy-based probiotic beverages are a plausible, safe adjunct for constipation.