Carbohydrate Reduction and Impact on Gastrointestinal System

University of Nottingham65 enrolled

Overview

Title : A pilot single blind randomised controlled trial of the effect of a diet low in poorly digested carbohydrates on gastrointestinal form and symptoms in irritable bowel syndrome patients Acronym: CRAIGS Short title: Carbohydrate reduction and impact on gastrointestinal system Chief Investigator: Prof Robin Spiller Objectives: The purpose of this study is to: * Investigate the proportion of patients with Irritable Bowel Syndrome who report moderate or substantial improvement in their symptoms after 2 weeks of following a diet low in Fermentable Oligo-Di-Monosaccharides and Polyols (FODMAPs) compared to patients who are on their habitual diet. * Determine the difference in colonic volume of IBS patients receiving immediate low FODMAP dietary intervention after 2 weeks compared to patients who are not on the diet (delayed dietary intervention). * Investigate the changes in self-reported food intolerance that occurs before dietary intervention. Trial Configuration: 2-arm, parallel group, randomised, controlled trial Setting : Research clinic within NIHR Biomedical Research Unit, Secondary care

TRIAL / STUDY OBJECTIVES AND PURPOSE The trial aims to investigate the effect of a diet low in FODMAPs on colonic morphology as well as in improving symptoms of irritable bowel syndrome (IBS). This mechanistic information, along with the clinical data, will allow planning of larger, multi-centre studies of the low FODMAP diet in similar patients. HYPOTHESES * Patients on a low FODMAP diet for 2 weeks will have a decreased fasting colonic volume measured by Magnetic Resonance Imaging (MRI) compared to participants who have not started the diet. * Patients with IBS are more likely to report a clinically important improvement in symptoms following the low FODMAP diet (immediate intervention) compared to those on their habitual diet (delayed intervention). PRIMARY OBJECTIVE • To compare the proportion of IBS patients reporting a clinically important improvement in symptoms following a low FODMAP diet for 2 weeks against IBS patients who are on their habitual diet. SECONDARY OBJECTIVES • Determine the difference in fasting colonic volume of IBS patients receiving low FODMAP dietary intervention after 2 weeks compared to those on habitual diet. TRIAL DESIGN This will be a pilot single-blind, randomised, controlled trial (RCT). Since some activity will take place on the University of Nottingham this will be a multi-centre study. All participants will receive advice from a dietitian on the low FODMAP diet. They will be randomised to one of two parallel treatment arms: 1. Low FODMAP dietary advice (immediate intervention) 2. Habitual diet (control - delayed intervention )

Study Type

Eligibility

Sex: ALLMin age: 18 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Aged 18 and above * Able to give informed consent * Previous Diagnosis of IBS by medical practitioner * Meeting ROME III criteria for IBS * Investigations showing negative tissue transglutaminase (tTG) IgA antibodies * Full blood count test does not indicate Anaemia Exclusion Criteria: * Inclusion * Aged 18 and above * Able to give informed consent * Previous Diagnosis of IBS by medical practitioner * Meeting ROME III criteria for IBS * Investigations showing negative tissue transglutaminase (tTG) IgA antibodies * Full blood count test does not indicate Anaemia Exclusion * Children (\<18 years) * History declared by the candidate of pre-existing gastrointestinal disorder, including but not limited to: * Inflammatory Bowel Disease * Coeliac Disease * Pancreatitis * Gallstone disease (biliary colic, cholecystitis) * Diverticulitis * Cancer of the gastrointestinal tract * Reported history of previous resection of any part of the gastrointestinal tract other than appendix or gallbladder * Intestinal stoma * Limited understanding of English * Pregnancy declared by the candidate * Red flag symptoms such as rectal bleeding, family history of bowel or ovarian cancer, a change in bowel habit to looser and/or more frequent stools persisting for more than six weeks in a person aged over 60 years. * Investigations showing positive tissue transglutaminase (tTG) IgA antibodies * Anaemia confirmed by full blood count test * Habitual use of opiate analgesics likely to alter bowel function e.g. morphine * Use of antibiotics in the preceding four weeks other than for treatment of index infection. * Any condition where the candidate is likely to require a course of antibiotics in the next 3 months e.g. severe chronic respiratory disease, recurrent urinary tract infection, lower limb ulceration * Inability to complete the symptom questionnaires e.g. cognitive dysfunction limiting memory and understanding * Anyone who in the opinion of the investigator is unlikely to be able to comply with the protocol e.g. chaotic lifestyle related to substance abuse * Dietary practice not compatible with safe implementation of the trial diet e.g.veganism * Medical reasons for pre-existing controlled diet that cannot be safely randomised e.g. end-stage kidney disease, diabetes * Participants taking prebiotic/probiotic

Outcomes

Primary Outcomes

Adequate symptom relief between cases and controls

Adequate symptom relief assessed by questionnaire after intervention in cases and before intervention in cases

Time frame: Assessed in cases on their last day of the intervention (2 weeks after dietary change). Assessed in controls before they began their intervention (between 1-2 weeks before dietary changes)

Secondary Outcomes

Changes in colonic volume between cases and controls from baseline

A change in colonic volume measured in milliliters (ml) from baseline and after intervention in cases. This will compared with a change in colonic volume from baseline and before intervention in controls.

Time frame: Measured : i) baseline (day 0), ii) last day of intervention (cases) (2 weeks after dietary change), iii) before intervention (2 weeks before dietary advice)

Changes in fermentation between cases and controls

A change in breath hydrogen concentration measured in parts per million (ppm) from: baseline and after intervention (cases) ii) from baseline and before intervention (controls)