Plain English Summary
Background and study aims
Irritable bowel syndrome (IBS) is a digestive disorder that affects up to 15% of the population. Symptoms include stomach pain, bloating and altered bowel habit. It can be very debilitating and has a great impact on quality of life. A diet with an altered amount of carbohydrates (e.g. the types of fruits and vegetables) might be effective for symptoms such as bloating, stomach pain and flatulence for many people with IBS. Recent research has shown that the diet described above can impact on the amount of bifidobacteria in the bowel. Probiotics are friendly bacteria added to foods that can increase the amount of bifidobacteria in the bowel. This study will investigate the effect of this diet with a probiotic food supplement on:
1. Bacteria in the bowel and the products of bacterial fermentation
2. Gut symptoms (e.g. wind, bloating)
3. Stool frequency and consistency
4. Dietary intake
5. Quality of life
We are also interested in the effect of dietary change on symptoms and the bacteria in the bowel in the longer term.
Who can participate?
Patients of Guy's and St Thomas' NHS Foundation Trust or St George's Healthcare Trust aged 18-65 years with IBS and without another major medical condition are eligible for this study. Other exclusion criteria apply regarding medication intake, types of symptoms and previous medical history, such as surgery.
What does the study involve?
The study incorporates three study centre visits, one before the 4-week study period, one after the 4-week study period and one visit at 12 months. There may also need to be one initial visit prior to the baseline visit in order to obtain consent if the patient is not identified in clinic, but screened from the referral letter.
What are the possible benefits and risks of participating?
There are no anticipated risks to participants; however, changes to dietary intake will be required for a 4-week period. Two stool samples will be collected and symptom, food and quality of life questionnaires will need to be completed. Routine dietary advice will be provided at the end of the study to all patients as per routine clinical care.
Where is the study run from?
The study will be run from Kings College London and St Georges Healthcare Trust
When is the study starting and how long is it expected to run for?
Recruitment will continue until September 2014.
Who is funding the study?
National Institute for Health Research (NIHR) (UK). Reimbursement for expenses will not be available for this study.
Who is the main contact?
Heidi Staudacher, Research Dietitian
heidi.staudacher@kcl.ac.uk
Trial website
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
N/A
Study information
Scientific title
The impact of dietary interventions for irritable bowel syndrome on luminal microbiota, symptoms, nutrient intake and quality of life: a randomised controlled trial
Acronym
Study hypothesis
Current study hypothesis as of 24/01/2013:
There is no difference in luminal bifidobacteria concentration between participants after four weeks of a sham diet versus four weeks of a treatment diet with added probiotic.
Previous study hypothesis until 24/01/2013:
There is no difference in luminal bifidobacteria concentration between participants after four weeks of a sham diet versus four weeks of a fermentable carbohydrate restriction with added probiotic.
On 17/07/2013 the anticipated end date was changed from 01/08/2014 to 30/09/2014.
On 05/08/2014 the target number of participants was changed from 93 to 100.
Ethics approval
NRES Committee London-Fulham, 08/10/2012, ethics no. 12/LO/1402
Study design
2 x 2 factorial design randomised controlled trial
Primary study design
Interventional
Secondary study design
Randomised controlled trial
Trial setting
Other
Trial type
Treatment
Patient information sheet
Not available in web format, please use the contact details below to request a patient information sheet
Condition
Irritable bowel syndrome
Intervention
Current interventions as of 24/01/2013:
4-week treatment diet + placebo
4-week treatment diet + added probiotic
4-week week sham diet + placebo
4-week sham diet + added probiotic
Previous interventions until 24/01/2013:
4-week fermentable carbohydrate restriction + placebo
4-week fermentable carbohydrate restriction + added probiotic
4-week week sham diet + placebo
4-week sham diet + added probiotic
Intervention type
Other
Phase
Not Applicable
Drug names
Primary outcome measures
1. Luminal bifidobacteria concentration between groups at 4 weeks
Added 05/08/2014:
2. Proportion of participants with adequate relief of IBS symptoms at 4 weeks
Secondary outcome measures
1. Difference in total and individual luminal gastrointestinal microbiota at 4 weeks
2. Difference in faecal short chain fatty acids and pH between groups at 4 weeks
3. Difference in IBS symptoms between groups at 4 weeks
4. Difference in stool consistency between groups at 4 weeks
5. Difference in nutrient intake between groups at 4 weeks
6. Difference in quality of life (QOL) scores between groups at 4 weeks
Overall trial start date
01/09/2012
Overall trial end date
30/09/2014
Reason abandoned
Eligibility
Participant inclusion criteria
1. Men and women aged 18-65 years with IBS-D, IBS-M or unsubtyped IBS based on Rome III criteria who do not have a major medical condition (diabetes, psychiatric or current eating disorders)
2. Gastrointestinal disease (e.g. inflammatory bowel disease, coeliac disease)
3. History of previous GI surgery, except cholecystectomy and haemorrhoidectomy
Participant type
Patient
Age group
Adult
Gender
Both
Target number of participants
100
Participant exclusion criteria
1. Females who report to be pregnant or lactating
2. Consumption of antibiotics, pre or probiotics (in food products or as supplements) in the last 4 weeks prior to, or during the study
3. Use of unpermitted medications (e.g. biological therapies)
4. Patients who have received bowel preparation for investigative procedures in the 4 weeks prior to the study
5. Patients who have had changes to IBS medications or dose in the 4 weeks prior to the study
6. Abdominal pain or discomfort for less than 2 days in the screening week, the frequency threshold recommended for clinical trials. Exclusion of those with minimal symptoms is recommended, and only those that experience pain on at least two days will be included.
7. Individuals with additional specific dietary needs
Recruitment start date
01/09/2012
Recruitment end date
30/09/2014
Locations
Countries of recruitment
United Kingdom
Trial participating centre
King's College London
London
SE1 9NH
United Kingdom
Sponsor information
Organisation
King's College London (UK)
Sponsor details
Diabetes and Nutritional Sciences
Franklin Wilkins Building
150 Stamford Street
London
SE1 9NH
United Kingdom
Sponsor type
University/education
Website
Funders
Funder type
University/education
Funder name
Current sources of funding as of 05/08/2014:
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Funder name
National Institute for Health Research (NIHR) (UK)
Alternative name(s)
NIHR
Funding Body Type
government organisation
Funding Body Subtype
Federal/National Government
Location
United Kingdom
Funder name
Previous sources of funding:
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Funder name
King's College London (UK)
Alternative name(s)
Funding Body Type
Funding Body Subtype
Location
Results and Publications
Publication and dissemination plan
Not provided at time of registration
Intention to publish date
Participant level data
Not provided at time of registration
Results - basic reporting
Publication summary