Functional dyspepsia Digestive System
Conditions
Interventions
Current interventions as of 19/12/2025:
The researchers are recruiting 126 patients as part of an observational study to look at the association between functional dyspepsia and ultra-processed food
Sponsors
University College London
Eligibility
Sex/Gender
All
Age
18 Years to 64 Years
Inclusion criteria
Inclusion criteria: 1. Adults aged =18 and <65 years old 2. Diagnosed with functional dyspepsia based on the Rome IV Clinical Diagnostic Criteria; bothersome epigastric pain or burning, early satiation, and/or postprandial fullness of greater than 8 weeks duration, and no evidence of structural disease (including at upper endoscopy) likely to explain the symptoms 3. Able to read and write in English 4. Willing and able to give written informed consent Additional inclusion (interventional phase): 1. A habitual diet high in UPF, as defined by =50% of total energy intake from UPFs 2. Women of childbearing potential (WOCBP) should have a negative urine beta human chorionic gonadotrophin (hCG) pregnancy test within 28 days of diet initiation and agree to use one established method of contraception throughout the study duration 3. Medically safe to participate in a dietary intervention programme 4. Able to comply with the study protocol, including dietary recommendations, attending sessions and confirming adherence throughout dietary recall
Exclusion criteria
Exclusion criteria: 1. Confirmed helicobacter pylori infection based on stool antigen test, rapid urease test (CLO), and/or histopathological assessment 2. Coeliac disease or villous atrophy 3. A diagnosed eating disorder 4. Body mass index (BMI) <18.5 or =45 kg/m2 5. Use of non-steroidal anti-inflammatory drugs or corticosteroids 6. Inflammatory bowel disease 7. Co-existent diagnosis of irritable bowel syndrome 8. Co-existent diagnosis of gastro-oesophageal reflux disease, functional heartburn or reflux hypersensitivity (bothersome retrosternal symptoms including discomfort, heartburn, regurgitation, and/or chest pain; intermittent symptoms not affecting quality of life are allowed) 9. Known structural disorder of the upper gastrointestinal tract (neoplasia, Barrett’s oesophagus, hiatus hernia =4 cm, oesophagitis =grade B, pharyngeal pouch, oesophago-gastric varices, erosive gastritis, active peptic ulcer disease, previous oesophago-gastric surgery) 10. Severe psychiatric disorder that might interfere with study participation or adherence 11. Women who are pregnant or breastfeeding 12. History of alcohol or substance abuse 13. Use of artificial nutrition Added 24/10/2025: 14. Any systemic disease or concomitant medication judged by the investigator to be a more likely explanation for the participant’s dyspeptic symptoms. Additional exclusion (interventional phase): 1. Contraindication for dietary intervention 2. Any diagnosed food allergy, or other allergies, which limit the ability to adhere to the intervention diet 3. Any major dietary restrictions which limit the ability to adhere to the dietary intervention 4. A suspected eating disorder based on the EDE-QS questionnaire 5. History of major cardiorespiratory co-morbidities (e.g. myocardial infarction, chronic heart failure exacerbation, stroke, TIA, or major event requiring hospitalisation within the last 6 months) 6. History of new or worsening signs or symptoms of coronary heart disease (CHD) within the last 3 months 7. Known case of symptomatic heart failure with reduced ejection fraction (NYHA Class II-IV) requiring pharmacologic therapy to control symptoms 8. Severe anaemia (=80 g/L) 9. Known case of severe peripheral vascular disease 10. History of moderate to severe chronic kidney disease (CKD) with an estimated glomerular filtration rate (eGFR) of < 30 mL/min/1.73m2 (estimated by Modification of Diet in Renal Disease (MDRD)), end-stage renal failure, or on dialysis 11. Symptomatic gallstones, symptomatic kidney stones, or acute cholecystitis 12. Clinically active systemic infection 13. Known history of chronic pancreatitis or a recent history of acute pancreatitis within the past year 14. History of active malignancy or partial remission from clinically significant malignancy within the past 5 years (except basal or squamous cell skin cancer, carcinoma in situ, those who received curative treatment and are in complete remission for 5 years, or if the subject is confirmed as cancer free) 15. Participation in another clinical intervention trial 16. Use of a neuromodulating agent (e.g. tricyclic anti-depressants, selective serotonin reuptake inhibitors, anti-psychotics, serotonin norepinephrine reuptake inhibitors, mirtazapine, etc) 17. Use of an anti-acid therapy (e.g. PPI, HR2A), which has been changed within the last four weeks and cannot remain stable for the duration of the trial. 18. Use of a medication that can affect the motility of the stomach (e.g. domperidone, metoclopramide, glucagon
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| 1. The proportion of ultra-processed food intake within the diet of individuals diagnosed with functional dyspepsia measured at screening using the Intake24 dietary recall questionnaire (=3 24-hour recalls over a 7-day period) that has been modified to account for ultra-processed food intake. 2. Gastrointestinal symptom severity measured using the Patient Assessment of Upper Gastrointestinal Symptom Severity Index (PAGI-SYM) at baseline, and 3-months | — |
Secondary
| Measure | Time frame |
|---|---|
| Observational cohort: 1. Gastrointestinal symptoms measured using patient assessment of upper gastrointestinal symptoms (PAGI-SYM) and the Visceral Sensitivity Index (VSI) at baseline stratified by groups based on UPF consumption 2. Quality of life measured using the Patient Assessment of Upper Gastrointestinal Disorders–Quality of Life (PAGI-QOL) and EQ-5D-5L at baseline stratified by groups based on UPF consumption 3. Psychological health measured using the Patient Health Questionnaire (PHQ-9) and the Generalised Anxiety Disorder Questionnaire (GAD-7) at baseline stratified by groups based on UPF consumption 4. Eating behaviour and patterns measured using the Food Frequency Questionnaire (FFQ) at baseline stratified by groups based on UPF consumption 5. Biometrics measured using bioelectrical impedance analysis at baseline stratified by groups based on UPF consumption Interventional cohort: 1. Gastrointestinal symptoms measured using PAGI-SYM, VSI at 1- and 3-months 2. Quality of life measured using PAGI-QOL, EQ-5D-5L at 1- and 3-months 3. Psychological health measured using PHQ-9, GAD-7 at 1- and 3-months 4. Biometrics measured using bioelectrical impedance analysis at 1- and 3-months 5. Eating behaviour and patterns measured using Intake24 at 1- and 3-months | — |
Countries
England, United Kingdom
Contacts
Public ContactBenjamin Norton
Outcome results
None listed