A randomized, double-blind, controlled human study: The efficacy of exopolysaccharides in milk fermented by Weissella confusa VP30 (VP30-EPS) to ameliorate functional constipation

[Display omitted] •Weissella confusa VP30 is a high EPS-producing probiotics.•A RCT (randomized, controlled clinical trial) was conducted to verify the constipation relieving efficacy of orally consumed Weissella confusa VP30’s exopolysaccharide in fermented milk.•The EPS-containing enriched fermented milk was effective in alleviating functional constipation symptoms. A randomized, double-blind, controlled human study was conducted to examine the effect of consuming exopolysaccharide (EPS) in milk fermented by Weissella confusa VP30 (VP30) on functional constipation. A total of 64 constipated adults, diagnosed by Rome III criteria for functional constipation, were randomized to receive either EPS-enriched VP30 fermented milk (VP30-EPS, n = 32) or an original VP30 fermented milk as a control fermented milk (CFM, n = 32) for 4 weeks. Questionnaires, which addressed defecation symptoms, dietary frequency and a dietary diary, were required to be completed every two weeks. Compared to the original VP30 fermented milk, EPS-enriched VP30 fermented milk was more effective in increasing defecation frequency, defecation volume, and fecal type during the 4-week treatment. The findings suggest that enrichment with EPS could improve indicators of bowel movement in individuals suffering from functional constipation. Constipation symptoms such as flatulence, pain, and bloating did not change to any statistically significant degree. The VP30-EPS group exhibited a greater decrease in the sum of symptoms scores from baseline to 4th week than the CFM group, which was marginally significant (p = 0.059). Changes in ammonia production and short chain fatty acid content were not statistically significant. Gut microbiome analysis showed the proportion of Bacteroidetes in the VP30-EPS group increased slightly while Firmicutes in the VP30-EPS group decreased slightly and Prevotella increased. To the best of our knowledge, this is the first study that shows the functional effect of reducing functional constipation through human clinical studies by applying EPS produced by a Weissella strain to a fermented dairy food.