Aliment Pharmacol Ther. 2022 Aug;56(4):592-605. doi: 10.1111/apt.17111.Epub 2022 Jul 1.

Jessica R Biesiekierski ^1 2, Lauren P Manning ², Helen Burton Murray ^3 4, Johan W S Vlaeyen ^5 6, Brjánn Ljótsson ⁷, Lukas Van Oudenhove ^8 9 10

Author information

¹Department of Nutrition, Dietetics and Food, Monash University, Notting Hill, Australia.

²Department of Food, Nutrition and Dietetics, La Trobe University, Melbourne, Australia.

³Center for Neurointestinal Health, Massachusetts General Hospital, Boston, Massachusetts, USA.

⁴Harvard Medical School, Boston, Massachusetts, USA.

⁵Research Group Health Psychology, KU Leuven, Leuven, Belgium.

⁶Research Group Experimental Health Psychology, Maastricht University, Maastricht, The Netherlands.

⁷Department of Clinical Neuroscience, Division of Psychology, Karolinska Institutet, Stockholm, Sweden.

⁸Laboratory for Brain-Gut Axis Studies (LaBGAS), Translational Research in Gastrointestinal Disorders (TARGID), Department of Chronic Diseases and Metabolism (CHROMETA), University of Leuven, Leuven, Belgium.

⁹Leuven Brain Institute, KU Leuven, Leuven, Belgium.

¹⁰Cognitive and Affective Neuroscience Lab, Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire, USA.

Abstract

Background: Irritable bowel syndrome (IBS) is a heterogeneous disorder of gut-brain interaction (DGBI) maintained by interacting biological, psychological, and social processes. Interestingly, there are two contrasting yet evidence-based treatment approaches for reducing IBS symptoms: exclusion diets such as those low in fermentable oligo-, di-, monosaccharides and polyols (FODMAPs) and exposure-based cognitive-behavioural therapy (CBT). Exclusion diets recommend patients avoid foods thought to be symptom-inducing, whereas exposure-based CBT encourages patients to expose themselves to foods.

Aims: To address the paradox of conceptually opposite exclusion diets and exposure-based CBT for IBS.

Methods: In this conceptual review, we describe the rationale, practical implementation, evidence base and strengths and weaknesses of each treatment. We conducted up-to-date literature search concerning the low FODMAP diet and CBT, and performed a secondary analysis of a previously conducted trial to illustrate a key point in our review.

Results: The low FODMAP diet has demonstrated efficacy, but problems with adherence, nutritional compromise, and heightened gastrointestinal-specific anxiety raise caution. Exposure-based CBT has demonstrated efficacy with substantial evidence for gastrointestinal-specific anxiety as a key mechanism of action. Mediation analysis also showed that increased FODMAP intake mediated decreased symptom severity in exposure-based CBT. However, there is minimal evidence supporting which treatment "works best for whom" and how these approaches could be best integrated.

Conclusions: Even though exclusion diets and exposure-based CBT are conceptually opposite, they each have proven efficacy. Clinicians should familiarise themselves with both treatments. Further research is needed on predictors, mechanisms and moderators of treatment outcomes.