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World J Gastrointest Surg. Sep 27, 2021; 13(9): 923-940
Published online Sep 27, 2021. doi: 10.4240/wjgs.v13.i9.923
How can probiotic improve irritable bowel syndrome symptoms?
Indira Benjak Horvat, Ivana Gobin, Andrea Kresović, Goran Hauser
Indira Benjak Horvat, Department of Gastroenterology, Varaždin General Hospital, Varažin 42000, Croatia
Ivana Gobin, Department of Microbiology and Parasitology, Faculty of Medicine, University of Rijeka, Rijeka 51000, Croatia
Andrea Kresović, Department of Gastroenterology, Clinical Hospital Center Rijeka, Rijeka 51000, Croatia
Goran Hauser, Department of Gastroenterology, Faculty of Medicine, Clinical Hospital Center Rijeka, University of Rijeka, Rijeka 51000, Croatia
Author contributions: Hauser G and Gobin I conceived the original idea; Benjak Horvat I, Gobin I and Kresović A performed a comprehensive review of all available literature, synthesised the data; Benjak Horvat I, Gobin I and Kresović A wrote the manuscript; Benjak Horvat I, Gobin I and Hauser G contributed to the study design and manuscript structure and performed a final critical appraisal of the manuscript; all authors read and approved the final manuscript.
Conflict-of-interest statement: We declare that there is no conflict of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Ivana Gobin, PhD, Associate Professor, Department of Microbiology and Parasitology, Faculty of Medicine, University of Rijeka, Braće Branchetta 20, Rijeka 51000, Croatia. ivana.gobin@uniri.hr
Received: February 14, 2021
Peer-review started: February 14, 2021
First decision: March 16, 2021
Revised: March 22, 2021
Accepted: August 6, 2021
Article in press: August 6, 2021
Published online: September 27, 2021
Processing time: 215 Days and 15.2 Hours
Abstract

The onset and manifestations of irritable bowel syndrome (IBS) is associated with several factors, and the pathophysiology involves various central and peripheral mechanisms. Most studies indicate that the management of gut microbiota could significantly affect the improvement of subjective disorders in patients with IBS. Numerous clinical trials have assessed the efficacy of probiotics for IBS with controversial conclusions. Several clinical trials have suggested that probiotics can improve global IBS symptoms, while others only improve individual IBS symptoms, such as bloating scores and abdominal pain scores. Only a few clinical trials have found no apparent effect of probiotics on IBS symptoms. Generally, probiotics appear to be safe for patients with IBS. However, the question of which probiotics should be used for certain IBS subtypes remains unresolved. In everyday practice, the dose of the recommended probiotic remains questionable, as well as how long the probiotic should be used in therapy. The use of probiotics in the M subtype and non-classified IBS is particularly problematic, in which combination therapy should be recommended due to the change in symptoms. Therefore, new approaches are needed in the design of clinical studies that should address certain subtypes of IBS.

Keywords: Irritable bowel syndrome; Obstipation; Diarrhoea; Abdominal pain; Probiotic; Prebiotic; Symbiotic; Microbiota

Core Tip: The onset and manifestations of irritable bowel syndrome (IBS) is associated with a number of factors, and the pathophysiology involves various central and peripheral mechanisms. The results of most studies indicate that influencing the gut microbiota could significantly affect the improvement of subjective disorders in patients with IBS. The most important open questions are the design of a clinical study in which the IBS subgroup is not initially defined and whether all IBS subtypes can be treated with the same probiotic or combination of probiotics. IBS subtype-designed clinical studies are urgently needed as a good foundation to define recommendations and guidelines for the use of probiotics in IBS.