Plain English Summary
Background and study aims
Inflammatory bowel disease (IBD) is a term used to describe conditions which cause long-term (chronic) inflammation (swelling) in the digestive tract (gut). The two main forms of IBD are Crohn’s disease (CD) and ulcerative colitis (UC). Crohn’s disease can affect any part of the gut, but is most common at the end of the ileum (the last part of the small intestine) or the colon (the large intestine). Ulcerative colitis generally affects the colon and rectum (the last part of the large intestine). There is currently no cure for these conditions, and so the main aim of treatment is to reduce the symptoms (remission) and prevent the disease from “flaring up” and becoming active again. Even when the disease is in remission, many patients still experience 'irritable bowel syndrome-like' symptoms, such as bloating, diarrhoea and abdominal (tummy) pain. It can greatly affect their quality of life and so these symptoms need to be well managed. In recent years, the link between diet and irritable bowel syndrome-like symptoms (IBS-like symptoms) has been extensively studied. It is thought that by eating or avoiding certain foods, it is possible improve IBS-like symptoms. The aim of this study is to find out whether a particular diet which involves food restrictions can help to improve IBS-like symptoms, and whether this diet changes the composition of bacteria in the gut in patients with inflammatory bowel disease in remission.
Who can participate?
Adults with inactive IBD who are experiencing ‘irritable bowel syndrome-like’ symptoms.
What does the study involve?
Patients who meet the initial screening criteria are asked to provide a stool sample and blood sample to measure levels of inflammatory markers. They are then asked to complete a 7-day food and symptom diary. If patients remain eligible based upon the severity of symptoms in this diary, they will be asked to return to the clinic to take part in the main study. These patients go to a clinic appointment which involves completing questionnaires and providing another stool and blood sample. The participants are then randomly allocated to one of two groups. Both groups are given dietary advice however the first group is put on a diet intended to help their IBS-like symptoms and the second group are put on a diet that is not expected to have any effect on their IBS-like symptoms. Participants are then asked to follow their diets for 4 weeks, keeping a food diary in the final week. All participants then return to the clinic for a follow up appointment, where they hand in their food diaries and provide another stool and blood sample.
What are the possible benefits and risks of participating?
Participants may benefit from an improvement to their IBS-like symptoms as a result of their new diet. There are no specific risks of taking part although some participants may experience pain, discomfort or bruising during blood tests.
Where is the study run from?
Guy’s and St Thomas NHS Foundation Trust and Barts Health NHS Trust (UK)
When is the study starting and how long is it expected to run for?
April 2015 to December 2017
Who is funding the study?
Kenneth Rainin Foundation (USA)
Who is the main contact?
Miss Selina Cox
Dietary interventions for the relief of functional gut symptoms in inflammatory bowel disease
The aim of this study is to find out whether a particular diet which involves food restrictions can help to improve IBS-like symptoms and whether this diet changes the composition of bacteria in the gut in patients with inflammatory bowel disease in remission.
Research Ethics Committee London – Dulwich, 22/10/2015, ref: 15/LO/1684
Randomised; Interventional; Design type: Treatment
Primary study design
Secondary study design
Randomised controlled trial
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Topic: Gastroenterology; Subtopic: Gastroenterology; Disease: All Gastroenterology
Participants are randomly allocated to one of two groups who will consume the intervention diet (expected to have an effect on IBS-like symptoms) or sham diet (expected to have no effect on IBS-like symptoms). Both diets will involve restriction of certain foods, e.g. rice, wheat, bananas, cucumber, berries, and appropriate alternative options will be provided so that nutritional adequacy can be maintained. All participants are provided with written information for the diet to which they have been allocated, outlining foods to avoid and those which are permitted during the trial, in addition to supplementary information. Researchers will contact participants weekly to answer any questions or respond to concerns, to monitor compliance to the diet and to document any adverse events.
Primary outcome measure
Gut symptoms are measured using the Irritable Bowel Syndrome Severity Scoring System score at baseline and 4 weeks.
Secondary outcome measures
1. Gastrointestinal symptoms are measured using the gastrointestinal symptom rating scale at baseline and 4 weeks
2. Stool output (frequency and consistency) is measured using the Bristol Stool Form Scale at baseline and 4 weeks
3. Luminal gastrointestinal microbiota composition, defined as total and individual bacteria and proportions of bacteria, are measured using quantitative polymerase chain reaction and metagenomic sequencingis measured at baseline and 4 weeks
4. Gastrointestinal microbiota metabolites, including SCFA, are measured using gas liquid chromatography at baseline and 4 weeks
5. Peripheral blood mononuclear cell gut homing phenotype, including cell surface homing receptors, measured using multi-colour flow cytometry at baseline and 4 weeks
6. Inflammatory markers, including faecal calprotectin, are measured using ELISA (enzyme linked immunosorbent assay) at baseline and 4 weeks
7. Clinical disease activity is measured using the Harvey-Bradshaw Index (for patients with Crohn’s disease) and the partial Mayo score (for patients with ulcerative colitis) at baseline and 4 weeks
8. Patient reported outcome measures are measured using the IBD-control questionnaire and patient-reported outcome 2 (PRO2) questionnaire at baseline and 4 weeks
9. Health-related quality of life is measured using the inflammatory bowel disease questionnaire and the food-related quality of life questionnaire at baseline and 4 weeks
10. Nutritional intake is measured using 7-day un-weighed food records at baseline and 4 weeks
Overall trial start date
Overall trial end date
Reason abandoned (if study stopped)
Participant inclusion criteria
1. Aged 18 years or over
2. Diagnosis of IBD confirmed by standard clinical, histological and radiological criteria for least 6 months
3. Inactive disease state (deemed in remission by physician assessment, with GI symptoms that have been assessed with objective investigations and thought not to be a result of active inflammation, and which do not require escalation of IBD
4. Stable medications (see exclusion criteria), and no GI surgery in preceding 6 months (also see exclusion criteria).
5. Have not experienced an IBD flareup in past 6 months
6. Faecal calprotectin <250µg/g (screening 2)
7. CRP <10mg/l (blood taken as part of routine outpatient appointment, but results checked during screening 2)
8. Functional symptoms meeting the following Rome III criteria:
8.1. IBS diarrhoea predominant, or IBS alternating subtype
8.2. Functional bloating
8.3. Functional diarrhoea
9. Symptoms must also meet the following criteria (screening 2):
9.1. Inadequate relief of gut symptoms at baseline according to the GSQ, assessed on day 7 of screening week
9.2. Presence of mild, moderate or severe abdominal pain, bloating or diarrhoea, assessed using the GSRS, on at least
2 of 7 days of the screening week
10. Have not been exposed to the intervention diet in the past
11. Ability to give informed consent
12. A willingness to participate
Target number of participants
Planned Sample Size: 52; UK Sample Size: 52
Total final enrolment
Participant exclusion criteria
1. Any evidence of active disease, defined as:
1.1. Requiring a change in treatment as assessed by the treating physician
1.2. Currently taking steroids
1.3. Patients in whom surgery is thought to be imminent
2. Changes in dose to azathioprine, 6mercaptopurine, methotrexate or antiTNFa agents during the preceding 12 weeks, oral 5ASA during the preceding four weeks.
3. Constipation predominant symptoms (either meeting criteria for IBSC or functional constipation)
4. Recent use of the following treatments: antibiotics or probiotics (or prebiotics) in the preceding eight weeks, NSAIDs
during the preceding week.
5. Pure perianal disease
6. Current stoma
7. Other factors likely to be cause of gut symptoms:
7.1. Previous extensive colonic resection, or extensive small intestinal resection indicating short bowel syndrome
7.2. Symptoms thought to relate to stenotic disease
7.3. Taking any medications with the potential to influence gastrointestinal symptoms, e.g. lactulose, loperamide, senna (unless taking longterm stable dose that is unlikely to change or stop during the trial)
7.4. Individuals with established bile acid malabsorption
8.1. Sepsis or fever
8.2. Diabetes or coeliac disease
8.3. Other concomitant serious comorbidity e.g. significant hepatic, renal, endocrine, respiratory, neurological or cardiovascular disease
9. Seen by a dietitian in the preceding 6 months for advice regarding nutrition support
10. Pregnancy or lactation
11. Full bowel preparation for a diagnostic procedure in preceding 4 weeks
Recruitment start date
Recruitment end date
Countries of recruitment
Trial participating centre
St Thomas' Hospital
Guy’s and St Thomas NHS Foundation Trust Westminster Bridge Road
Trial participating centre
The Royal London Hospital
Barts Health NHS Trust Whitechapel Road
Trial participating centre
Great Maze Pond
Kenneth Rainin Foundation
Rainin Foundation, KRF
Funding Body Type
private sector organisation
Funding Body Subtype
Trusts, charities, foundations (both publically funded and privately funded)
United States of America
Results and Publications
Publication and dissemination plan
The results will be published in peer-reviewed scientific journals, in addition to presentation at relevant conferences.
Intention to publish date
Participant level data
Not expected to be available
Basic results (scientific)
2019 results in: https://www.ncbi.nlm.nih.gov/pubmed/31586453 (added 07/10/2019)