Therapeutic Potential of the Low-Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols Diet in Functional Dyspepsia: A Systematic Review

INTRODUCTION: Dietary factors, including fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs), have been implicated in symptom generation among patients with functional dyspepsia (FD). Accordingly, a low-FODMAP diet (LFD) has been proposed as a potential therapeutic approach. However, no systematic review has yet been conducted. This study aimed to evaluate the effects of an LFD on gastrointestinal symptoms and quality of life (QoL) in patients with FD. METHODS: Following PRISMA guidelines, Medline, Embase, and Central were searched through October 2025. Studies involving adults or children diagnosed with FD and treated with a structured LFD or lower habitual FODMAP intervention were included. Randomized controlled trials (RCTs) and non-RCTs were assessed for methodological quality using the Cochrane RoB 2 tool and the Newcastle-Ottawa Scale, respectively. RESULTS: Ten studies involving 4,329 patients (two RCTs and eight non-RCTs) met the inclusion criteria. Both RCTs demonstrated significant improvements in dyspeptic symptoms and QoL following an LFD compared with the control or baseline. Non-RCTs consistently showed symptom relief and improved QoL in adults and children under dietitian supervision, whereas lower habitual FODMAP intake was associated with a higher risk of FD prevalence in cross-sectional studies. Overall, the studies exhibited a predominantly moderate risk of bias. CONCLUSION: Current evidence suggests that an LFD may alleviate gastrointestinal symptoms and enhance QoL in patients with FD. However, existing studies remain few and heterogeneous. High-quality, adequately powered clinical and mechanistic studies are warranted to confirm its therapeutic efficacy and clarify the underlying physiological mechanisms.