Fermentable Carbohydrates [FODMAPs] Exacerbate Functional Gastrointestinal Symptoms in Patients With Inflammatory Bowel Disease: A Randomised, Double-blind, Placebo-controlled, Cross-over, Re-challenge Trial

J Crohns Colitis. 2017 Dec 4;11(12):1420-1429. doi: 10.1093/ecco-jcc/jjx073.


Background and aims: Preliminary evidence suggests that fermentable carbohydrate restriction might ameliorate functional gastrointestinal symptoms [FGS] in inflammatory bowel disease [IBD]. Our aim was to determine whether fermentable carbohydrates exacerbate FGS in IBD using a randomised, double-blinded, placebo-controlled, re-challenge trial.

Methods: Patients with quiescent IBD and FGS responsive to a low FODMAP diet were allocated to a series of 3-day [d] fermentable carbohydrate challenges in random order [fructan, 12 g/d; galacto-oligosaccharides [GOS] 6 g/d; sorbitol, 6 g/d; and glucose placebo, 12 g/d], each separated by a washout period. Symptoms and stool output were measured daily during the challenges.

Results: Thirty-two patients with IBD, fulfilling criteria for irritable bowel syndrome, functional bloating, or functional diarrhoea, were recruited and data were available for 29 patients completing all arms [12 Crohn's disease, 17 ulcerative colitis]. Significantly fewer patients reported adequate relief of FGS on the final day day of the fructan challenge [18/29, 62.1%] compared with glucose [26/29, 89.7%] [p = 0.033]. There was greater severity of pain [1.1 vs 0.5, p = 0.004], bloating [1.3 vs 0.6, p = 0.002], flatulence [1.5 vs 0.7, p = 0.004], and faecal urgency [0.9 vs 0.4, p = 0.014] on the final day of fructan challenge compared with glucose.

Conclusions: At the relatively high doses used, fructans, but not GOS or sorbitol, exacerbated FGS in quiescent IBD. Further research is required to determine whether a low FODMAP diet reduces FGS in IBD and the degree of FODMAP restriction required for symptom improvement.

Keywords: FODMAPs; Inflammatory bowel disease; functional gastrointestinal symptoms.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Abdominal Pain / etiology
  • Adult
  • Aged
  • Colitis, Ulcerative / diet therapy
  • Colitis, Ulcerative / physiopathology*
  • Crohn Disease / diet therapy
  • Crohn Disease / physiopathology*
  • Cross-Over Studies
  • Defecation
  • Diarrhea / etiology
  • Dietary Carbohydrates / adverse effects*
  • Dietary Carbohydrates / metabolism
  • Double-Blind Method
  • Feces / chemistry
  • Female
  • Fermentation
  • Flatulence / etiology
  • Fructans / adverse effects*
  • Galactose / adverse effects
  • Humans
  • Leukocyte L1 Antigen Complex / analysis
  • Male
  • Middle Aged
  • Oligosaccharides / adverse effects*
  • Sorbitol / adverse effects*
  • Symptom Assessment
  • Young Adult


  • Dietary Carbohydrates
  • Fructans
  • Leukocyte L1 Antigen Complex
  • Oligosaccharides
  • Sorbitol
  • Galactose