The aim of this randomized double-blind placebo-controlled study was to evaluate the effectiveness and safety of multi-strain probiotic in adults with diarrhea-predominant irritable bowel syndrome (IBS-D). The patients were randomized to receive a mixture of Lactobacillus, Bifidobacterium, and Streptococcus thermophilus strains or placebo for eight weeks. Primary endpoints included changes in symptom severity and improvement assessed with the IBS Severity Scoring System (IBS-SSS) and Global Improvement Scale (IBS-GIS). The probiotic in comparison with placebo significantly improved the IBS symptom severity (the change of total IBS-SSS score from baseline ‒165.8 ± 78.9 in the probiotic group and ‒105.6 ± 60.2 in the placebo group, p = 0.005) and in the specific scores related to the severity of pain (p = 0.015) and the quality of life (p = 0.016) after eight weeks of intervention. The probiotic group indicated an improvement in symptoms with the use of the IBS-GIS compared with the placebo group after four (p = 0.04) and eight weeks (p = 0.003). The occurrence of adverse events did not differ between study groups. In conclusion, the multi-strain probiotic intervention resulted in a significant improvement in IBS symptoms evaluated with the use of both IBS-SSS and IBS-GIS scales. The results suggest that the studied probiotic preparation is well tolerated and safe and can offer benefits for patients with IBS-D. (registration number in Clinicaltrials.gov NCT04662957).
Keywords: Bifidobacterium; IBS-GIS; IBS-SSS; Lactobacillus; irritable bowel syndrome; probiotics.