The Effects of Fermentable Oligo-, Di-, and Monosaccharides and Polyols on Dyspeptic Symptoms: A Systematic Review and Meta-Analysis of Clinical Trials

Abstract

Background and Aims Conflicting evidence is available regarding the effects of fermentable oligo-, di-, and monosaccharides and polyols (FODMAP) on dyspeptic symptoms. Therefore, this systematic review and meta-analysis was performed to assess the effects of FODMAPs on dyspeptic symptoms.Methods A systematic search up to October 2025 was performed through PubMed, ISI Web of Science, Scopus, Cochrane Library, and EMBASE. Randomized controlled trials (RCTs) and non-randomized studies of interventions (NRSIs) examined the impact of the low-FODMAP diet (LFD) as the intervention group and the high-FODMAP diet (HFD) as the control diet on dyspeptic symptoms, including early satiety, pain, bloating, fullness, and nausea were included. The search strategy involved combining FODMAP-related terms with dyspeptic terms and symptoms. The mean severity of dyspeptic symptoms was pooled using a random-effects model and was reported as the weighted mean difference (WMD) and 95 confidence interval (CI). The certainty of the evidence was assessed with the Grading of Recommendations Assessment, Development and Evaluation (GRADE).Results A total of 12 studies (6 RCTs and 6 NRSIs) were eligible for inclusion in this meta-analysis. Compared with an HFD, an LFD significantly decreased the severity of bloating (WMD = -0.36, 95 CI: -0.58, -0.14; I2 = 88.3, n = 8) and early satiety (WMD = -0.69, 95 CI: -0.92, -0.46; I2 = 86.3, n = 8). However, compared with an HFD, an LFD was associated with greater abdominal pain scores (WMD = 0.34, 95 CI: 0.11, 0.56; I2 = 34.5, n = 7) but did not influence nausea (WMD = 0.12, 95 CI: -0.09, 0.32; I2 = 0.0, n = 7) or fullness severity (WMD = -1.63, 95 CI: -2.92, -0.35; I2 = 98.4, n = 3).Conclusion An LFD significantly reduced the severity of bloating and early satiety. However, these findings were substantially heterogeneous, and the certainty of the evidence was very low, which needs to be confirmed by further RCTs.