The Effect of low-FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet on clinical symptoms and quality of life in patients with non-ulcer dyspepsia: a randomized controlled trial
Investigating the Effect of a Low-FODMAP Diet on Clinical Symptoms and quality of life in patients with Non-Ulcer Dyspepsia
Design
This single-blind randomized trial evaluates the effect of a low-FODMAP diet on clinical symptoms and quality of life. The study includes 50 patients with non-ulcer dyspepsia, randomly assigned to either a low-FODMAP or standard diet group. Patients will be followed for 12 weeks. Randomization is performed using the RAND function in Excel.
Settings and conduct
The study will be conducted at the Behbood Gastroenterology and Hepatology Clinic in Tehran. Eligible patients will be enrolled after screening by a gastroenterology specialist and obtaining informed consent. Baseline data will be collected, and patients will be randomly assigned to either the intervention group (low-FODMAP diet) or the control group (standard diet). The intervention group will receive dietary guidance from a nutritionist, while the control group will follow a regular diet. Patients will be monitored every 4 weeks over 12 weeks for symptom severity, quality of life, and diet adherence. The study will be single-blind, with symptom assessors and data analysts unaware of group assignments.
Participants/Inclusion and exclusion criteria
Inclusion Criteria:
Age over 18 years
Diagnosis of functional dyspepsia based on Rome IV criteria
History of dyspeptic symptoms for at least 6 months
Willingness and ability to adhere to a low-FODMAP diet (LFD)
Absence of other gastrointestinal diseases
No regular use of nonsteroidal anti-inflammatory drugs
Not pregnant or breastfeeding
Exclusion Criteria
Unwillingness to participate in the study
Non-adherence to the intervention
Diagnosis of a new gastrointestinal disease
Regular use of NSAIDs
Intervention groups
Low-FODMAPs diets
Main outcome variables
Clinical symptoms and quality of life
General information
Reason for update
Acronym
IRCT registration information
IRCT registration number:IRCT20100524004010N41
Registration date:2025-03-24, 1404/01/04
Registration timing:prospective
Last update:2025-03-24, 1404/01/04
Update count:0
Registration date
2025-03-24, 1404/01/04
Registrant information
Name
Azita Hekmatdoost
Name of organization / entity
Shahid Beheshti University of Medical Sciences, National Institute of Nutrition Research
Country
Iran (Islamic Republic of)
Phone
+98 21 2293 0824
Email address
hekmat@sina.tums.ac.ir
Recruitment status
Recruitment complete
Funding source
Expected recruitment start date
2025-04-05, 1404/01/16
Expected recruitment end date
2025-10-08, 1404/07/16
Actual recruitment start date
empty
Actual recruitment end date
empty
Trial completion date
empty
Scientific title
The Effect of low-FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet on clinical symptoms and quality of life in patients with non-ulcer dyspepsia: a randomized controlled trial
Public title
The Effect of low-FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet on clinical symptoms and quality of life in patients with non-ulcer dyspepsia: a randomized controlled trial
Purpose
Treatment
Inclusion/Exclusion criteria
Inclusion criteria:
Age over 18 years
Diagnosis of functional dyspepsia based on Rome IV criteria
History of dyspeptic symptoms for at least 6 months
Willingness and ability to adhere to the Low FODMAP Diet (LFD)
No other gastrointestinal diseases, such as Crohn’s disease, ulcerative colitis, or celiac disease
No regular use of nonsteroidal anti-inflammatory drugs (NSAIDs)
Not pregnant or breastfeeding
Exclusion criteria:
Unwillingness to continue the study
Non-adherence to the intervention
The occurrence of any serious adverse effects
Becoming pregnant
Development of any new gastrointestinal disease
Regular use of NSAIDs
Age
From 18 years old
Gender
Both
Phase
N/A
Groups that have been masked
Data analyser
Data and Safety Monitoring Board
Sample size
Target sample size:
50
Randomization (investigator's opinion)
Randomized
Randomization description
For the random allocation of participants into the intervention and control groups, each individual will be assigned a numerical code, which will then be entered into a table of random numbers. Based on the first randomly selected number from the table, participants will be sequentially assigned to one of the two groups. This process will continue until all participants have been allocated to either group. Randomization will be conducted by an individual independent of the intervention team to ensure impartiality.
Blinding (investigator's opinion)
Single blinded
Blinding description
Collected data will be coded (e.g., Group A and Group B) before being provided to the data analysts.
Statistical analyses will be conducted without knowledge of group allocation.
This approach prevents potential bias in the interpretation of results.
Placebo
Not used
Assignment
Parallel
Other design features
Secondary Ids
empty
Ethics committees
1
Ethics committee
Name of ethics committee
Ethics Committee of National Nutrition and Food Technology Research Institute (NNFTRI)
At the beginning of the study, the first month, and the third month
Method of measurement
GSRS Scale for Functional Dyspepsia
2
Description
Quality of life
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
Short-Form Nepean Dyspepsia Index (SF-NDI)
Secondary outcomes
1
Description
Upper Abdominal Pain
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
GSRS Scale for Functional Dyspepsia
2
Description
Bloating
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
GSRS Scale for Functional Dyspepsia
3
Description
Early Satiety
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
GSRS Scale for Functional Dyspepsia
4
Description
Nausea
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
GSRS Scale for Functional Dyspepsia
5
Description
Belching
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
GSRS Scale for Functional Dyspepsia
6
Description
Has your general emotional well-being been disturbedby your stomach problems in the last 2 weeks?
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
Short-Form Nepean Dyspepsia Index (SF-NDI)
7
Description
Have you been irritable, tense or frustrated in thelast 2 weeks because of your stomach problems?
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
Short-Form Nepean Dyspepsia Index (SF-NDI)
8
Description
Has your ability to engage in things you usually do for fun (recreations, going out, hobbies, sports, etc.) been disturbed by your stomach problems in the last 2 weeks?
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
Short-Form Nepean Dyspepsia Index (SF-NDI)
9
Description
Has your enjoyment of things you usually do for fun (recreations, going out, hobbies, sports, etc.) been disturbed by your stomach problems in the last 2 weeks?
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
Short-Form Nepean Dyspepsia Index (SF-NDI)
10
Description
Has your ability to eat or drink (including when, what, and how much) been disturbed by your stomach problems in the last 2 weeks?
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
Short-Form Nepean Dyspepsia Index (SF-NDI)
11
Description
Has your enjoyment of eating and/or drinking been disturbed by your stomach problems in the last 2 weeks? (Please also include your appetite, and howyou feel after food or drink).
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
Short-Form Nepean Dyspepsia Index (SF-NDI)
12
Description
Have you wondered whether you will always have these stomach problems, in the last 2 weeks?
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
Short-Form Nepean Dyspepsia Index (SF-NDI)
13
Description
Have you thought that your stomach problems might be due to a very serious illness (e.g. cancer or a heart problem), in the last 2 weeks?
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
Short-Form Nepean Dyspepsia Index (SF-NDI)
14
Description
Has your ability to work or study been disturbed by your stomach problems in the last 2 weeks?
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
Short-Form Nepean Dyspepsia Index (SF-NDI)
15
Description
Has your enjoyment of work or study been disturbed by your stomach problems in the last 2 weeks?
Timepoint
At the beginning of the study, the first month, and the third month
Method of measurement
Short-Form Nepean Dyspepsia Index (SF-NDI)
Intervention groups
1
Description
Control group: The control group will continue their regular weight-maintenance diet without any restrictions on FODMAP intake for 12 weeks. Clinical symptoms and quality of life will be assessed at baseline and after 4 weeks using standardized questionnaires. This diet includes the following guidelines: 1. Eat slowly and regularly. 2. Reduce fat intake. 3. Follow a diet that closely resembles the Mediterranean diet or increase the consumption of fresh foods while reducing ultra-processed foods. 4. Avoid triggers such as spicy foods, carbonated drinks, tea, coffee, alcohol, smoking, and NSAIDs. 5. Consume small, frequent meals.
Category
Other
2
Description
Intervention group: The intervention group will follow a weight-maintenance diet with low fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (Low FODMAP), designed by a registered dietitian. This diet includes restrictions on foods high in FODMAPs, such as legumes, dairy products, certain fruits, and vegetables. In **Phase I (Weeks 0–4)**, patients in both groups will receive comprehensive oral and written dietary instructions from a trained dietitian. These instructions will include detailed recommendations on which foods to avoid or reduce and suitable alternatives. The dietitian will contact patients at the end of weeks 1, 4, and 12 to address any questions or concerns and to collect 3-day food records. Additionally, patients will have unlimited access to the dietitian for further consultation. In **Phase II (Weeks 5–12)**, after four weeks, a 3-day food record and symptom assessment will be collected. Patients will also complete the **Short-Form Nepean Dyspepsia Index (SF-NDI) for quality of life** and the **Gastrointestinal Symptom Rating Scale (GSRS) for functional dyspepsia symptoms, including the functional dyspepsia module**. Patients whose 3-day dietary recall shows a FODMAP intake of less than 20 grams will proceed to Phase II. The intervention group will receive revised instructions for continuing the low FODMAP diet, while the control group will continue following their initial dietary guidelines. At the **end of the study (Week 12)**, a 3-day food record and symptom assessment will again be collected, and patients will complete the **SF-NDI and GSRS (functional dyspepsia and dyspepsia module)**. Dietary compliance and any adverse effects will be recorded.
Category
Other
Recruitment centers
1
Recruitment center
Name of recruitment center
Behbood Gastroenterology and Hepatology Clinic
Full name of responsible person
Azita Hekmatdoost
Street address
Behbood Gastroenterology and Hepatology Clinic, No. 2, Corner of Alley 14, Beginning of North Mofatteh, Shahid Beheshti Street**
City
Tehran
Province
Tehran
Postal code
1985717413
Phone
+98 21 8817 1901
Email
info@clinicbehbood.com
Sponsors / Funding sources
1
Sponsor
Name of organization / entity
Shahid Beheshti University of Medical Sciences
Full name of responsible person
Afshin Zarghi
Street address
Deputy of Research & Technology, Shahid Beheshti University of Medical Sciences, Velenjak
City
Tehran
Province
Tehran
Postal code
1981619573
Phone
+98 21 23871
Email
a_hekmat2000@yahoo.com
Grant name
Grant code / Reference number
Is the source of funding the same sponsor organization/entity?
No
Title of funding source
Shahid Beheshti University of Medical Sciences
Proportion provided by this source
100
Public or private sector
Public
Domestic or foreign origin
Domestic
Category of foreign source of funding
empty
Country of origin
Type of organization providing the funding
Academic
Person responsible for general inquiries
Contact
Name of organization / entity
Shahid Beheshti University of Medical Sciences
Full name of responsible person
Azita Hekmatdoost
Position
Professor
Latest degree
Ph.D.
Other areas of specialty/work
Nutrition
Street address
No 7, Shahid Hafezi Ave, Farahzadi Blvd, Western Qods Town
City
Tehran
Province
Tehran
Postal code
1981619573
Phone
+98 21 2235 7483
Fax
Email
a_hekmat2000@yahoo.com
Web page address
Person responsible for scientific inquiries
Contact
Name of organization / entity
Shahid Beheshti University of Medical Sciences
Full name of responsible person
Azita Hekmatdoost
Position
Professor
Latest degree
Ph.D.
Other areas of specialty/work
Nutrition
Street address
No 7, Shahid Hafezi Ave, Farahzadi Blvd, Western Qods Town
City
Tehran
Province
Tehran
Postal code
1981619573
Phone
+98 21 2293 0824
Email
a_hekmat2000@yahoo.com
Person responsible for updating data
Contact
Name of organization / entity
Shahid Beheshti University of Medical Sciences
Full name of responsible person
Azita Hekmatdoost
Position
Professor
Latest degree
Ph.D.
Other areas of specialty/work
Nutrition
Street address
No 7, Shahid Hafezi Ave, Farahzadi Blvd, Western Qods Town
City
Tehran
Province
Tehran
Postal code
1981619573
Phone
+98 21 2293 0824
Email
a_hekmat2000@yahoo.com
Sharing plan
Deidentified Individual Participant Data Set (IPD)
Undecided - It is not yet known if there will be a plan to make this available
Study Protocol
Undecided - It is not yet known if there will be a plan to make this available
Statistical Analysis Plan
Undecided - It is not yet known if there will be a plan to make this available
Informed Consent Form
Undecided - It is not yet known if there will be a plan to make this available
Clinical Study Report
Undecided - It is not yet known if there will be a plan to make this available
Analytic Code
Undecided - It is not yet known if there will be a plan to make this available
Data Dictionary
Undecided - It is not yet known if there will be a plan to make this available