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

Abstract Background Individuals with Irritable Bowel Diseases (IBS) have a higher risk of mental disorders. However, management on IBS still focuses on gastrointestinal symptoms, often ignoring psychological comorbidities, which might lead to suboptimal therapeutic outcomes. The purpose of the study was to investigate the current state of IBS treatment at our center and further to explore whether dietary intervention could alleviate anxiety burden.Methods We prospectively enrolled two cohorts of IBS patients. The first one was an observational study that was designed to assess the prevalence of anxiety and the current status of treatment. The other one was conducted to explore the efficacy of low FODMAP diet (LFD). Finally, stool samples were collected before and after the LFD intervention analyzed by 16s rRNA sequencing.Results Anxiety was present in approximately 60% of IBS patients in our cohort but was consistently ignored in the conventional therapy. Anxiety was positively correlated with IBS discomfort syndromes. Rifaximin was the only effective drug among the standard therapeutic options. The one-month LFD intervention could greatly alleviate both abdominal and mental disorders in IBS patients. Though α- and β-diversity of gut bacteria were similar between diet responders and non-responders, the composition of dominate bacteria was significantly different. At the genus level, responders exhibited higher abundances of Klebsiella, Parabacteroides, and Lactobacillus compared to non-responders.Conclusions Anxiety is common in IBS patients, yet it is frequently neglected in standard treatment. The LFD diet emerges as a promising therapeutic approach, potentially exerting its benefits through specific gut microbiota.