Gastrointestinal System - Irritable Bowel Syndrome

Following a low-FODMAP diet (LFD) for >2 weeks may improve irritable bowel syndrome (IBS) symptoms, quality of life and bowel habits (e.g. stool frequency, stool consistency) but may have no effect on anxiety and depression scores in adults with all irritable bowel syndrome subtypes. 

The LFD may negatively affect microbiome diversity (especially Bifidobacterium and short-chain fatty acid contents) and gastrointestinal pH in adults with all IBS subtypes. Higher quality, longer-term research is necessary to elucidate the full effects. 

A 2024 systematic umbrella review of 11 meta-analyses and 24 RCTs concluded that following the LFD for >2 weeks may improve IBS symptoms (weighted mean difference (WMD), -44.97) and IBS Symptom Severity Scale (IBS-SSS) scores (RR, 1.42) in adults with all IBS subtypes. Grade of Evidence B   Quality of life (WMD, 3.53), stool consistency (WMD, -0.48) and stool frequency (WMD, -0.36) were improved by the LFD, although anxiety and depression scores were not. However, gastrointestinal pH and microbiome diversity, especially Bifidobacterium and short-chain fatty acid contents, may be negatively affected. It should be noted that most research on the LFD has only considered the elimination phase of the diet, and the effects of an LFD during the reintroduction and personalization phases are not known. Grade of Evidence C

Examples of low and high FODMAP foods from the Monash Univeresity where foods have been analyzed is available from: https://www.monashfodmap.com/about-fodmap-and-ibs/

See Additional Content: For individuals restricting their diet to manage irritable bowel syndrome (IBS) symptoms, what are the nutrition and safety concerns?