Gut & Microbiome
low-FODMAP diet treats irritable bowel syndrome
Strong support Gut & Microbiome
RefutedContestedStrong support
consensus score 0.66
📅 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)
MechanismIn-vitroAnimalObservationalRCTMeta-analysis
How the studies fall
10 support 0 contradict 0 tested null 5 mixed · 15 sources, 10 independent groups · 1 superseded — pooled inside a review, counted once
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, Zhang Y, Gao Z, Yuan X, Li X 2026 · BMC gastroenterology | 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, Shui X 2026 · Clinical nutrition (Edinburgh, Scotland) | 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, Dbar SR, Sabelnikova EA, Belostotsky NI, Parfenov AI 2026 · Terapevticheskii arkhiv | 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, Huerta-de la Torre MF, Arenas-Martinez JS, Coss-Adame E 2026 · Alimentary pharmacology & therapeutics | 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, Horvath A, Kozłowska-Jalowska A, Muir J, Szajewska H 2026 · Frontiers in pediatrics | 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, Power VA, Shepherd SJ, Gibson PR, Muir JG 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 ↩ SUPERSEDED — pooled in the review above, counted once |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 · Gastroenterology | 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 · Frontiers in nutrition | observational | supports | low | Retrospective online survey n=98: 90.7% reported symptom reduction after LFD; bloating MD -5.03 (p<.001) |
| Thuen C, Kenter RMF, Assmus J, Steinsvik EK, Vikøren LAS, Lied GA, Berentsen B 2026 · Internet interventions | 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, Malinowska U, Daniluk J 2025 · Frontiers in nutrition | 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, Celano G, Dargenio VN, Apa CA, Amendolara M, Stella M, Castellaneta S, Barone M, Vacca M, De Angelis M, Francavilla R 2026 · Alimentary pharmacology & therapeutics | 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, Laforce S, Tremblay M, Mukaneza Y, Rose C, Bémeur C 2026 · Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme | observational | supports | low | single-arm pilot n=15/35 completers, 6mo online LFD: IBS-SSS improved 276→200 (p<.05); QoL only trend |
| Cuffe MS, Staudacher HM, Aziz I, Adame EC, Krieger-Grubel C, Madrid AM, Ohlsson B, Black CJ, Ford AC 2025 · Lancet Gastroenterol Hepatol | meta-analysis | supports | moderate | Network meta-analysis of 28 randomised trials (2338 patients, 11 diets). For global IBS symptoms a low FODMAP diet ranked fourth among diets tested in more than one trial (RR of symptoms not improving 0·51, 95% CI 0·37-0·70; P-score 0·71; from 24 trials) versus habitual diet; a starch- and sucrose-reduced diet ranked first (0·41, 0·26-0·67; two trials). Low FODMAP also beat habitual diet for bloating (0·55, 0·37-0·80; 23 trials); for bowel habit no diet beat any control. The authors rate the low-FODMAP-versus-habitual comparison moderate confidence and most of the network low or very low. |
| Roth B, Ohlsson B 2026 · Nutrition and health | 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 · The Turkish journal of gastroenterology : the official journal of Turkish Society of Gastroenterology | 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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