Effect of a Low- Fermentable-Oligo-Di- Monosaccharides and Polyols Diet Group Intervention on IBS Symptoms and Fatigue

Irritable bowel disease (IBS) is a functional gastrointestinal disorder that affects 10% of the population. Comorbidities are common and fatigue is the most common extraintestinal complaint in IBS patients. There are no cure for the disease but there are nutrition treatments that can relieve symptoms. The main goal of this randomized controlled trial is to test the hypothesis that low-Fermentable- oligo-di- monosaccharides and polyols (FODMAPs) diet kan decrease gastrointestinal symptoms and improve quality of life and fatigue in patients with IBS.

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by stomach pain at least one day a week accompanied by change in stool frequency or appearance. Prevalence of IBS is about 10 % of the population worldwide and more common in women. IBS is divided into different subclasses: diarrhea predominant, (IBS-D), predominant constipation, (IBS-C), mixed bowel habits, (IBS-M). Comorbidities are common and fatigue is the most common extraintestinal complaint among the patients. Patients has severely reduced quality of life, reduced work capacity and the cost are substantial for the patients and the society. IBS can´t be cured but the symptoms can be relieved by pharmacological as well as non-pharmacological treatment as psychological- and nutritional treatment. The main goal of this randomized controlled trial is to test the hypothesis that low FODMAPdiet kan decrease gastrointestinal symptoms and improve quality of life and fatigue in patients with IBS.

FODMAPs is an acronym for Fermentable-Oligo-Di-Monosaccharides and Polyols. FODMAPs are carbohydrates that can't be absorbed/splinted in the large intestine and they ferment rapidly and exacerbate gastrointestinal symptoms as flatulence, pain, bloating and loose stools. In total 120 patients with IBS-D and IBS-M will be randomized to immediate treatment start or delayed treatment start. The treatment will be performed in clinical setting, led by a dietitian and in group format including 12 patients in each group. The intervention time is 12 weeks with 5 group visits at a gastroenterology unit. The low-FODMAP treatment is divided into three steps: elimination of FODMAPs, re-introduction and personalization of the diet. Compliance to the diet will be measured by monitoring the FODMAP intake from three day food diaries and a compliance form. Questionnaires will be self reported in a web based application. Food diaries and the stomach diary will be filled out at baseline, at week 5, 12 and 6, 12 and 24 months post intervention.

Eligibility Criteria:
Inclusion criteria:

* Established IBS-D by RomeIV- criteria
* Established IBS-M by RomeIV- criteria
* Body Mass Index (BMI)18-35

Exclusion criteria:

* Pregnancy
* Lactation
* Ongoing eating disorder/ contact with eating disorder unit
* Postoperative gastrointestinal surgery that may impact on the gastrointestinal function
* Celiac disease
* Psychiatric disorder
* Other disorder that may impact the possibility to participate in group treatment
* Diabetes
* Ongoing low- FODMAPdiet treatment.