Completed

High vs. Low FODMAP Diets and Metformin Impact on Glucose Response and Gut Microbiota in Prediabetes

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Study Aim

This study aims to compare the impact of high and low FODMAP diets, along with Metformin, on your blood sugar levels and gut bacteria, if you have prediabetes.

What is being tested

High FODMAP diet with metformin

+ Low FODMAP diet with metformin

Combination Product
Who is being recruted

Diabetes Mellitus+5

+ Endocrine System Diseases

+ Hyperglycemia

From 18 to 70 Years
+23 Eligibility Criteria
See all eligibility criteria
How is the trial designed

Prevention Study

Placebo-Controlled
Interventional
Study Start: November 2022
See protocol details

Summary

Principal SponsorElaine Chow
Last updated: January 28, 2026
Sourced from a government-validated database.Claim as a partner

Study start date: November 11, 2022

Actual date on which the first participant was enrolled.

This study explores how diets with different FODMAP levels (FODMAPs are certain types of carbohydrates) and a medication called metformin affect blood sugar levels after meals and gut bacteria in individuals with prediabetes. The research aims to understand the best dietary approach to manage blood sugar levels and improve gut health in this population, potentially preventing the progression to diabetes. Participants will follow two different diets, one high in FODMAPs and one low in FODMAPs, each for a period of 10 days. During the last 5 days of each diet, they will also take metformin. There will be a break of at least 2 weeks between the two diet periods. The study measures the changes in blood sugar levels after meals using continuous glucose monitoring, and assesses the impact on gut bacteria and digestive comfort.

Official TitleThe Impact of High or Low FODMAP Diets on Postprandial Glucose Response and Gut Microbiota in Individuals With Prediabetes Treated With Metformin: A Randomized Crossover Controlled-Feeding Trial
NCT05628584
Principal SponsorElaine Chow
Last updated: January 28, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details

26 patients to be enrolled

Total number of participants that the clinical trial aims to recruit.

Prevention Study

Prevention studies aim to stop a disease from developing. They often involve people at risk and test things like vaccines, lifestyle changes, or preventive medications.

Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria

Any sex

Biological sex of participants that are eligible to enroll.

From 18 to 70 Years

Range of ages for which participants are eligible to join.

Healthy volunteers not allowed

If individuals who are healthy and do not have the condition being studied can participate.

Conditions

Pathology

Diabetes MellitusEndocrine System DiseasesHyperglycemiaMetabolic DiseasesNutritional and Metabolic DiseasesPrediabetic StateGlucose IntoleranceGlucose Metabolism Disorders

Criteria

3 inclusion criteria required to participate
Age 18-70 years
Body mass index 18 to 40 kg/m 2
Prediabetes defined as impaired fasting PG 5.6-6.9 mmol/l and/or impaired glucose tolerance with 2-hour PG 7.8-11.1 mmol/l on 75g oral glucose tolerance test (OGTT) and/or HbA1c 5.7-6.4% at screening
20 exclusion criteria prevent from participating
Current use or recent exposure to any medication that in the opinion of the investigator could have an influence on the patient's ability to participate in this study or on the performance of the test device
Currently pregnant, lactating, as demonstrated by a positive pregnancy test at screening or planning pregnancy
Known current diabetes
Current or previous use of glucose-lowering or weight loss drugs in 3 months prior to screening
Show More Criteria

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives

2 intervention groups are designated in this study

50% chance of being blinded to the placebo group

Treatment Groups

Group I

Experimental
Participants in this group follow a controlled High FODMAP diet (15g/day) for the first ten days, and also take metformin XR 1000mg daily from day six to ten of each treatment period.

Group II

Placebo
Participants in this group follow a controlled low FODMAP diet for the first 10 days and also take Metformin XR 1000mg daily from day 6 to day 10 of each treatment period. This group is a placebo comparator, meaning their results will be compared to those of a group not receiving the same treatment.

Study Objectives

Primary Objectives

Secondary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.

This study has 1 location

Suspended

Prince of Wales Hospital

Shatin, Hong KongOpen Prince of Wales Hospital in Google Maps
CompletedOne Study Center