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Review
. 2025 Jan 7;17(1):e77053.
doi: 10.7759/cureus.77053. eCollection 2025 Jan.

The Efficacy of the Low-FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) Diet in Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis

Zahid Khan  1   2   3 , Syed Aun Muhammad  4 , Mehul S Amin  5 , Amresh Gul  6
Affiliations
Review

The Efficacy of the Low-FODMAP (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) Diet in Irritable Bowel Syndrome: A Systematic Review and Meta-Analysis

Zahid Khan et al. Cureus. .

Abstract

Irritable bowel syndrome (IBS) is frequently observed in clinical practice and affects people from different parts of the world. The pathogenesis and aetiology are not well-defined or fully understood; however, altered bowel movements, psychological factors, and visceral hypersensitivity may contribute to symptoms via a pathway mediated by serotonin and other enteric neurotransmitters. Altered bowel movements, including diarrhoea and constipation, abdominal pain relieved by passing flatus, and bloating are the main salient features of this condition. This systematic review and meta-analysis aimed to determine the effectiveness and efficacy of a low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (low-FODMAP) diet in these patients. Systematic searches were conducted on PubMed, Medline, Google Scholar, and Cochrane Library. Randomised controlled trials (RCTs), systematic trials and cohort studies that included keywords about IBS and a low-FODMAP diet were included. Exclusion criteria included studies that were not in the English language, not relevant to IBS, diet-related to inflammatory bowel disease, or not pertinent to the subject. A total of 41 studies were included in this systematic review and meta-analysis. There was significant heterogeneity among the RCTs; hence, a random-effects model was used. The systematic review included a total of 8460 patients across 36 studies, with follow-up durations ranging from 11 to 16 months. Specifically, the meta-analysis included 15 RCTs with 1118 participants and follow-up durations from two days to nine weeks and six cohort studies including 292 patients with follow-up durations from two weeks to two years. The risk ratio (RR) was 1.21 (95% confidence interval= 0.98-1.51), and the I2 value ​​​​​was 63% for global symptom improvement with a low-FODMAP diet using a random-effects model. There was a low risk of bias in the RCTs. Five studies were included evaluating the effect of a low-FODMAP diet on quality of life, and these studies did not show any statistically significant benefit of a low-FODMAP diet on quality of life, although a mean difference of 4.59 (95% CI 1.50-7.67) was observed. The risk of bias was moderate to severe in the observational studies included in this review. Food intolerance is increasingly recognised as a contributory factor in IBS, and its role in the pathogenesis and precipitation of symptoms is being explored. Specific mechanisms include the fermentation of FODMAPs by the gut microbiota, leading to gas production and subsequent symptoms.

Keywords: british dietetic association; general dietary advice; high-fodmap diet; ibs (irritable bowel syndrome); ibs-sss; irritable bowel syndrome with diarrhea; low-fodmap diet; medical subject headings; structural individual low fodmap dietary advice; treatment of irritable bowel syndrome.

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Conflict of interest statement

Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

Figures

Figure 1
Figure 1. Schematic representation of IBS pathophysiology and various factors considered to be involved in the generation of IBS symptoms.
Permission was obtained from the authors for the reproduction and reuse of this figure [17]. IBS: Irritable bowel syndrome
Figure 2
Figure 2. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) chart showing the literature methodology.
Figure 3
Figure 3. The risk of bias assessment traffic light chart for randomised controlled trials included in the meta-analysis.
Figure 4
Figure 4. The risk of bias plot for randomised controlled trials included in the meta-analysis showing risk of bias by percentage.
Figure 5
Figure 5. Risk of bias assessment traffic light chart using ROBINS-E for observational studies showing moderate to high risk of bias.
ROBINS-E: Risk Of Bias In Non-randomized Studies - of Interventions
Figure 6
Figure 6. The risk of bias assessment by percentages for the observational studies included in this review.
Figure 7
Figure 7. Forest plot for the randomised controlled trials included in the meta-analysis.
Figure 8
Figure 8. Funnel plot for the studies included in the meta-analysis.
Figure 9
Figure 9. Forest plot for quality of life in the low-FODMAP diet versus placebo group.
FODMAP: Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols
Figure 10
Figure 10. Funnel plot for studies reporting quality of life in patients included in this meta-analysis.
Figure 11
Figure 11. Forest plot showing values for global symptom improvement for the observational studies included in this systematic review.
Figure 12
Figure 12. The role of SCFAs in the pathogenesis of IBS by modulating the modulate intestinal epithelial immunity and inflammation, maintaining gut barrier integrity, altering gut motility, and acting as part of the microbiota-gut-brain axis.
Permission was obtained from the authors to reproduce this image [67]. SCFA: Short-chain fatty acid; IBS: Irritable bowel syndrome
See this image and copyright information in PMC

References

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