Disorders of gut–brain interaction in patients with IBD
Emma Halmos, D-ECCO Member
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Up to one-third of patients with Inflammatory Bowel Disease (IBD) have persistent bowel symptoms despite apparent control of intestinal inflammation [1]. These symptoms fit with irritable bowel syndrome (IBS), a type of disorder of gut–brain interactions (DGBI). DGBI respond poorly to the pharmacological agents that are typically used to target inflammation in IBD. Thus, as clinicians, our challenges are to identify IBS-like symptoms, which is more easily achieved in those with quiescent disease, and to find suitable treatments for control of non-inflammatory symptoms.
Diagnosis of DGBI
Diagnosis of DGBI is difficult and is fraught with confounding factors owing to reliance on symptom-based criteria that are not necessarily appropriate in the presence of IBD. In many studies, definition of DGBI in the IBD population is on the basis of ‘clinical remission’, which is dependent upon physician global assessment and biochemical markers such as serum C-reactive protein (CRP) and faecal calprotectin, with debate about optimal levels that reflect quiescent disease [2]. Emerging data indicate that intestinal ultrasound may be an accurate tool for identification of truly quiescent IBD, with a recent study finding that 61% of patients with Crohn’s Disease in clinical remission (based on disease activity scores) had disease activity on intestinal ultrasound [3]. Further investigation into the best tools to identify quiescent IBD and overcome the limitations of symptom-based assessment is much needed.
Management of DGBI
Most data relating to the management of DGBI in patients with IBD are ‘borrowed’ from the general IBS population. The only therapy with randomised controlled trial evidence of effectiveness for the treatment of DGBI symptoms in quiescent IBD is the low FODMAP diet. The first pilot trial provided carefully designed low and typical FODMAP diets to nine patients with quiescent Crohn’s Disease in a cross-over design, which halved symptoms to a level considered clinically good [4]. This observation was replicated in a well-powered study of 52 quiescent IBD patients with IBS-like symptoms, with achievement of adequate symptom relief in >50% patients compared with 16% on the control diet [5]. These data indicate that the low FODMAP diet has good efficacy for the treatment of IBS-like symptoms in IBD, but concerns have been raised regarding its safety [6]. In the general IBS community, studies assessing the safety of the low FODMAP diet have been reassuring. Risks of nutritional inadequacy, negative psychosocial effects and adverse impact on microbiota are minimised if use of the diet is guided by a dietitian and personalised reintroduction of FODMAPs is achieved [7, 8]. However, such safety evaluations have not been conducted in IBD patients, who arguably would be at higher risk of such effects. A ‘FODMAP-gentle’ dietary approach has been suggested in this and other at-risk populations [9], but this approach has not yet been evaluated. Further research on the safety of the low FODMAP diet and ways to reduce dietary burden in IBD patients is eagerly awaited.
References
- Fairbrass KM, Costantino SJ, Gracie DJ, Ford AC. Prevalence of irritable bowel syndrome-type symptoms in patients with inflammatory bowel disease in remission: a systematic review and meta-analysis. Lancet Gastroenterol Hepatol 2020;5:1053–62.
- Colombel JF, Shin A, Gibson PR. AGA Clinical practice update on functional gastrointestinal symptoms in patients with inflammatory bowel disease: Expert review. Clin Gastroenterol Hepatol 2019;17:380–90.e1.
- Vaughan R, Tjandra D, Patwardhan A, et al. Toward transmural healing: Sonographic healing is associated with improved long-term outcomes in patients with Crohn's disease. Aliment Pharmacol Ther 2022;56:84–94.
- Halmos EP, Christophersen CT, Bird AR, et al. Consistent prebiotic effect on gut microbiota with altered FODMAP intake in patients with Crohn's disease: A randomised, controlled cross-over trial of well-defined diets. Clin Transl Gastroenterol 2016;7:e164.
- Cox SR, Lindsay JO, Fromentin S, et al. Effects of low FODMAP diet on symptoms, fecal microbiome, and markers of inflammation in patients with quiescent inflammatory bowel disease in a randomized trial. Gastroenterology 2020;158:176–88.e7.
- Thomassen RA, Luque V, Assa A, et al. An ESPGHAN position paper on the use of low-FODMAP diet in pediatric gastroenterology. J Pediatr Gastroenterol Nutr 2022;75:356–68.
- Staudacher HM, Ralph FSE, Irving PM, et al. Nutrient intake, diet quality, and diet diversity in irritable bowel syndrome and the impact of the low FODMAP diet. J Acad Nutr Diet 2020;120:535–47.
- Staudacher HM, Rossi M, Kaminski T, et al. Long-term personalized low FODMAP diet improves symptoms and maintains luminal Bifidobacteria abundance in irritable bowel syndrome. Neurogastroenterol Motil 2022;34:e14241.
- Halmos EP, Gibson PR. Controversies and reality of the FODMAP diet for patients with irritable bowel syndrome. J Gastroenterol Hepatol 2019;34:1134–42.