Contents lists available at ScienceDirect Complementary Therapies in Medicine journal homepage: www.elsevier.com/locate/ctim Probiotics, prebiotics, and low FODMAP diet for irritable bowel syndrome – What is the current evidence? Soo Liang Ooi, Dianne Correa, Sok Cheon Pak ⁎ School of Biomedical Sciences, Charles Sturt University, Bathurst, NSW 2795, Australia ARTICLEINFO Keywords: Irritable bowel syndrome IBS Probiotics Prebiotics Synbiotics FODMAP Systematic review Meta-analysis ABSTRACT Irritable bowel syndrome (IBS) is one of the most common functional gastrointestinal disorders worldwide. While the pathogenesis is not clearly understood, current research points to the role of the gut microbiome and alterations in the diversity of the microbiota. Probiotics, prebiotics, and low FODMAP diet are therapeutic means associated with modifcation of the gut microbiome for the alleviation of IBS symptoms. This narrative review assesses the current evidence on the efcacy of these treatment options based on fndings from recent systematic reviews and meta-analyses published from October 2013 to October 2018. There is a general agreement in the 11 included systematic reviews and meta-analyses that probiotic therapy is safe and can be efective in improving overall IBS symptom scores and abdominal pain in the general IBS population. Nonetheless, conficting fndings remain and no recommendation on the specifc species/strains or combination can be made. Short-term restriction of FODMAP in the diet can improve IBS symptoms as per the fndings of 7 systematic reviews and meta-analyses, even though the quality of the evidence remains questionable. Inappropriate use of the low FODMAP diet can potentially impact health negatively. As such, a low FODMAP diet is only re- commended as a second line treatment guided by qualifed clinicians with specialized training. Despite preclinical studies of some prebiotics demonstrated the potential use in improving gut microbiome and intestinal infammatory response, the benefcial efect of prebiotics for IBS remains theoretical. Two sys- tematic reviews found no evidence to support the clinical use of prebiotics for IBS. 1. Introduction Irritable bowel syndrome (IBS) is one of the most common func- tional gastrointestinal disorders with a global prevalence of about 11%. 1 This condition afects more women than men. IBS is defned by recurring abdominal pain associated with defecation and/or a change in bowel habits, typically accompanied by symptoms of abdominal bloating/distension. 2 The diagnosis of one of the specifc IBS subtypes depends on the predominant bowel habits, such as constipation, diar- rhea, multi-type, or unspecifed IBS. 2–5 The current diagnostic criteria for IBS (Rome IV) are summarized in Table 1. While the pathogenesis is not clearly understood, current research points to the role of the gut microbiome and alterations in the diversity of the microbiota (referred to as ‘dysbiosis’), specifcally a decrease in Lactobacillus and Bifido- bacterium species. 4–6 Dysbiosis activates the immune system and leads to low-grade infammation of the gut, and thus disrupts the gut-brain axis interaction. 3,5,6 Probiotics, prebiotics, and low FODMAP diet are therapeutic means associated with modifcation of the gut microbiome for the alleviation of IBS symptoms. These therapies have received much research focus in recent years. 6–10 This review aims to assess the current evidence on the efcacy of these treatment options for IBS. We conducted searches in research databases (Pubmed, Cochrane Library, Scopus, and Web of Science) to identify relevant studies with the keywords (prebiotics OR probiotics OR FODMAP AND irritable bowel syndrome). With the bulk of avail- able clinical trials and reviews on this topic, we selected only the sys- tematic reviews and meta-analyses of human clinical trials published within the 5-year period from October 2013 to October 2018. Our search yielded 267 unique records after removing the duplicates. After screening and assessing for eligibility, a total of 18 studies are included for information synthesis and a narrative review. 2. Probiotics According to the World Health Organization defnition, probiotics are living bacteria which confer health benefts on the host when https://doi.org/10.1016/j.ctim.2019.01.010 Received 11 December 2018; Accepted 15 January 2019 ⁎ Corresponding author at: School of Biomedical Sciences, Charles Sturt University, Panorama Avenue, Bathurst, NSW, 2795, Australia. E-mail address: spak@csu.edu.au (S.C. Pak). Complementary Therapies in Medicine 43 (2019) 73–80 Available online 16 January 2019 0965-2299/ Crown Copyright © 2019 Published by Elsevier Ltd. All rights reserved. T