Health Psychology Research / HPR / Online First / DOI: 10.14440/hpr.0363
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RESEARCH ARTICLE

Therapeutic Effects of a Low FODMAP Diet on Symptoms, Gut Microbiota, and Anxiety in Patients with Irritable Bowel Syndrome

Hui Tao1† ,  Liu Ying Li1† ,  Lu Chen1† ,  Heng Lu1 ,  Hui Shi1 ,  Fang Yu Wang1 ,  Zhao Yang1* ,  Wei Chen1* ,  Lei Ye2*
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1 Department of Gastroenterology and Hepatology, Jinling Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210002, Jiangsu, China
2 Department of Gastroenterology, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
HPR, e81240063 https://doi.org/10.14440/hpr.0363
Submitted: 8 November 2025 | Revised: 8 January 2026 | Accepted: 13 January 2026 | Published: 26 February 2026
© 2026 by the Author(s). This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution -Noncommercial 4.0 International License (CC-by the license) ( https://creativecommons.org/licenses/by-nc/4.0/ )
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Abstract

Background

Individuals with irritable bowel syndrome (IBS) are at an elevated risk for mental disorders. However, IBS management often overlooks psychological factors, which may contribute to suboptimal therapeutic outcomes.

Objective

This study aims to assess the current treatment approach for IBS at our center, Jinling Hospital of Nanjing and investigate whether dietary interventions, specifically the low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet (low FODMAP diet; LFD), could alleviate anxiety symptoms in IBS patients.

Methods

We prospectively enrolled two cohorts of IBS patients. The first cohort underwent an observational study to assess the prevalence of anxiety and evaluate current treatment approaches. The second cohort participated in a clinical trial evaluating the efficacy of the LFD. Stool samples were collected before the LFD intervention and analyzed using 16S rRNA sequencing.

Results

Anxiety was present in approximately 60% of IBS patients in our cohort, but it was frequently overlooked in conventional treatment. Anxiety was positively correlated with IBS symptom severity. Rifaximin was the only standard therapeutic option demonstrating efficacy. A one-month LFD intervention significantly reduced both gastrointestinal and mental health symptoms in IBS patients. Although α- and β-diversity of the gut microbiota were similar between diet responders and nonresponders, the composition of dominant bacteria differed significantly. At the genus level, responders exhibited higher abundances of Klebsiella, Parabacteroides, and Lactobacillus than non-responders.

Conclusion

Anxiety is common in IBS patients but often neglected in standard treatment protocols. The LFD may serve as an alternative therapeutic approach, potentially exerting benefits through modulation of gut microbiota.

Keywords
Irritable bowel syndrome
Low FODMAP diet
Anxiety
Gut microbiota
Clinical cohort
Funding
This work was funded by the National Natural Science Foundation of China (82170574) and the Hospital Innovation and Technology Research Project (2024JSYXQN066).
Conflict of interest
The authors declare no conflict of interest.
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