Efficacy of a low-FODMAP diet in adult irritable bowel syndrome: a systematic review and meta-analysis

Purpose This review provides an updated overview of observational and intervention studies investigating the effect of a low-FODMAP (fermentable oligo-, di- and monosaccharides, and polyols) diet (LFD) on gastrointestinal (GI) symptoms, quality of life (QoL), nutritional adequacy, and gut microbiome in irritable bowel syndrome (IBS) patients. Methods We systematically searched available literature until October 2020 for studies that investigated the effect of LFDs on GI symptoms, QoL, nutritional adequacy, and the gut microbiome in IBS patients. The data were represented as standardized mean differences (SMD) for IBS severity, and as mean differences (MD) for IBS-QoL. Meta-analyses were performed for the quantitative analyses using random effects models with inverse variance weighing. Results Twelve papers (nine parallel trials, three crossover studies) were included for the meta-analysis. The LFD reduced IBS severity by a moderate-to-large extent as compared to a control diet (SMD - 0.66, 95% CI - 0.88, - 0.44, I-2 = 54%). When analyzing only studies that used the validated IBS-SSS questionnaire, a mean reduction of 45 points (95% CI - 77, - 14; I-2 = 89%) was observed. Subgroup analyses on adherence, age, intervention duration, IBS subtype, outcome measure, and risk of bias revealed no significantly different results. The LFD also increased IBS-QoL scores, when compared with a control diet (MD 4.93; 95% CI 1.77, 8.08; I-2 = 42%). Conclusions The low-FODMAP diet reduces GI symptoms and improves quality of life in IBS subjects as compared to control diets. Future work is required to obtain definitive answers regarding potential long-term effects of such diets on nutritional adequacy and the gut microbiome. PROSPERO registration number CRD42020175157.

Automated summary

The low-FODMAP diet is effective in reducing symptoms severity and improving quality of life in patients with irritable bowel syndrome, regardless of age, intervention duration, and IBS subtype. Future research should focus on the long-term effects of such diets on nutritional adequacy and the gut microbiome.