Effect of a new synbiotic supplement on symptoms, stool consistency, intestinal transit time and gut microbiota in patients with severe functional constipation: a pilot randomized double-blind, controlled trial

Data on the benefits of synbiotics in functional constipation are conflicting. The aim of this study was to assess whether the administration of the synbiotic supplement Psyllogel Megafermenti(®) normalized stool consistency and decreased intestinal transit time (ITT) in patients with severe functional constipation, based on its ability to impact on the gut microbiota.We conducted a pilot randomized, double-blind, controlled trial. After a 2-week run-in period, patients from a tertiary care setting with severe functional constipation fulfilling the Rome III Diagnostic Criteria in the past year were randomly assigned to receive by mouth 2 bags/day of Psyllogel Megafermenti(®) (Group A) or 2.8 g of maltodextrin twice daily (Group B) for 8 weeks. Primary endpoints were increase of bowel evacuations with normal stool consistency and volume, and ITT reduction. Secondary endpoints included symptom improvement according to the Rome III Diagnostic Criteria, reduction of the Agachan-Wexner score and changes in gut microbiota composition.Twenty-nine patients completed the study: 17 were allocated to Group A and 12 to Group B. A statistically significant increase in stools with normal consistency was observed only in Group A (p = 0.001), even when considering patients with normal stools ≤50 % of time at baseline. In Group A, a significant reduction in ITT was also found (p = 0.022). According to polymerase chain reaction-denaturing gradient gel electrophoresis profiling of stool samples, 50 % of the patients treated with synbiotics harbored all the probiotic species of the study product.An 8-week treatment with Psyllogel Megafermenti(®) improved the main clinical parameters of functional constipation in patients extremely homogeneous for disorder severity and underlying pathophysiology ( Eudract.ema.europa.eu , No. 2008-000913-30).