A Randomized, Double-Blind, Placebo-Controlled Trial to Evaluate the Effects of Multi-Strain Synbiotic in Patients with Functional Diarrhea and High Fecal Calprotectin Levels: A Pilot Study.

Nutrients. 2022;14(23)
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Functional diarrhoea (FDr) is defined as having more than 25% loose or watery stools (Bristol stool type 6 or 7) beginning at least 6 months ago and lasting for the last 3 months but without predominant abdominal pain or bothersome bloating. The aim of this study was to investigate the effects of a multi-strain synbiotic compared to placebo on bowel symptoms, changes in the intestinal microenvironment, and safety in adults with bowel discomfort and watery or loose stools after 8 weeks of intervention. This study was a double-blind randomised controlled study. Patients were randomised to the placebo (20 patients) or synbiotic group (20 patients) with a 1:1 allocation. Results showed that the daily intake of multiple strains and fructo-oligosaccharide [oligosaccharide] for 8 weeks were effective in improving the degree of formed stool and patient-self reported bowel movement satisfaction compared to placebo in FDr patients with high faecal calprotectin levels. Furthermore, there was a significant increase in Lactobacillales at the order level in the faecal microbiome analysis of the synbiotic group. Authors conclude that their findings provide a basis for improving bowel symptoms in FDr patients.


Synbiotics, including probiotics and prebiotics, are useful for patients with functional bowel disorders. However, which synbiotics are beneficial for patients with which diseases, especially those with functional diarrhea (FDr) with high fecal calprotectin levels, is currently unknown. FDr is an extension of irritable bowel syndrome with diarrhea (IBS-D). Although fewer studies have been conducted on FDr compared to IBS-D, its importance is increasing as its prevalence increases. The aim of this study was to evaluate the effects of a synbiotic containing a mixture of Lactobacillus and Bifidobacterium and its substrate, fructooligosaccharide, on bowel symptoms, fecal calprotectin levels, fecal microbiota, and safety in FDr patients with high fecal calprotectin levels. Forty patients were randomly assigned to either a synbiotic group or a placebo group. A total of 20 subjects in the synbiotic group and 19 subjects in the placebo group completed the study (8 weeks). Changes in FDr symptoms, fecal calprotectin levels, and gut microbiota were assessed during the intervention period. At 4 and 8 weeks, the number of bowel movements tended to increase in the synbiotic group, with a significant increase in the number of formed stools rather than loose stools (p < 0.05). Bowel movement satisfaction was significantly increased in the synbiotic group, but not in the placebo group. Intestinal flora analysis revealed that Lactobacillales at the order level was increased only in the synbiotic group at the end of the intervention. In contrast, at week 8 of the intervention, log-transformed fecal calprotectin levels were significantly decreased in the synbiotic group, although the change was not significantly different from that of the placebo group. These findings suggest that the intake of a multi-strain-containing synbiotic for 8 weeks could improve gut symptoms and the intestinal microenvironment of FDr patients with high fecal calprotectin levels.

Lifestyle medicine

Fundamental Clinical Imbalances : Digestive, absorptive and microbiological
Patient Centred Factors : Triggers/Synbiotic
Environmental Inputs : Nutrients ; Microorganisms
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Stool
Bioactive Substances : Synbiotics ; Probiotics

Methodological quality

Jadad score : 4
Allocation concealment : Yes


Nutrition Evidence keywords : Synbiotic ; Probiotics