Gut & Microbiome
low-FODMAP diet treats irritable bowel syndrome
📅 Last reviewed: 2026-07-15 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: All trials, pooled (Meta-analysis)
How the studies fall
What the evidence shows
Low-FODMAP diet reduces global IBS symptoms — best-evidenced dietary therapy.
The evidence (16)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Zhao Y et al 2026 · study_type: observational | observational | supports | low | Retrospective cohort n=196 (LFD+care 112 vs conventional 84), 6wk: IBS-SSS pain severity/frequency/bloating all improved (p=.01-.006) vs conventional |
| Yang X et al 2026 · study_type: meta-analysis | meta-analysis | mixed | moderate | MA of 10 RCTs/939pts: LFD responder 34-78%, but no sig diff vs other dietary interventions pooled (RR=1.04, 95%CI 0.91-1.19, p=.55, I2=0%) |
| Bykova SV et al 2026 · study_type: observational | observational | mixed | low | n=20 IBS pts, pre-post 2mo LFD: only bloating & diarrhea improved significantly (p<.05); pain/nausea not reported significant |
| Garcia-Cedillo MF et al 2026 · study_type: RCT | RCT | mixed | moderate | RCT n=69: adequate relief 54.5% personalised-FODMAP vs 41.2% NICE advice (p=.33), no sig between-group difference |
| Stróżyk A et al 2026 · study_type: RCT | RCT | mixed | low | Early-terminated peds RCT n=38: responder 7/13 LFD vs 5/13 regular diet (RR 1.4, 95%CI 0.6-3.3), no sig diff in responder proportion |
| Halmos EP, et al. 2014 · Gastroenterology | RCT | supports | moderate | Landmark crossover RCT: low-FODMAP cut GI symptom VAS to 22.8 vs 44.9 (p<0.001); ~70% improved. ↩ SUPERSEDED — pooled in the review above, counted once |
| staudacher-2017 2017 | RCT | supports | moderate | RCT (2x2 factorial, n=104): adequate relief 57% low-FODMAP vs 38% sham; IBS-SSS fell (diet effect p=0.001); depleted Bifidobacterium. |
| Bogdanowska-Charkiewicz D et al 2026 · study_type: observational | observational | supports | low | Retrospective online survey n=98: 90.7% reported symptom reduction after LFD; bloating MD -5.03 (p<.001) |
| Thuen C et al 2026 · study_type: RCT | RCT | mixed | moderate | 4-arm RCT n=642 (373 analyzed): FODMAP-module add-on responder 42.6-45.1% across all arms, OR 0.97 (95%CI 0.54-1.72), p=.989 vs education alone |
| Bogdanowska-Charkiewicz D et al 2025 · study_type: meta-analysis | meta-analysis | supports | moderate | Umbrella review, 16 MAs/141 studies/9904 pts: IBS-SSS SMD=-0.599 (5 MAs, n=3761), QoL SMD=0.259 (p<.0001); no sig effect on pain/stool freq/consistency/microbiota |
| Cristofori F et al 2026 · study_type: RCT | RCT | supports | moderate | Paediatric crossover n=66: responder (≥50% pain reduction) 57.6% LFD vs 30.3% habitual diet (p=.024); IBS-SSS also reduced |
| Hogue C et al 2026 · study_type: observational | observational | supports | low | single-arm pilot n=15/35 completers, 6mo online LFD: IBS-SSS improved 276→200 (p<.05); QoL only trend |
| Cuffe M, et al. 2025 · Lancet Gastroenterol Hepatol | meta-analysis | supports | high | Low-FODMAP diet ranked among most efficacious dietary interventions for global IBS symptoms. |
| Roth B et al 2026 · study_type: RCT | RCT | supports | moderate | RCT n=155 (SSRD 77 vs LFD 78), 4wk: both reduced food-triggered-symptom proportion but different food-group patterns; no global-symptom RR given here |
| Yang X. 2026 · Research Square | meta-analysis | supports | moderate | Network MA, 10 RCTs/939pts: all specific diets beat habitual diet/control; LFD P-score=0.60 (4th of 5), MED-LFD highest (0.76); TDA lower (0.20) |
| Somtaş AE et al 2026 · study_type: RCT | RCT | supports | moderate | 3-arm RCT n=63, 4wk; LFD & GFD both cut IBS-SSS vs baseline (P<.001) but no between-group difference in symptom severity (P>.05); QoL differed |
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Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.