ClinicalTrials.gg
CompletedNCT05628584Updated Mar 5, 2025

High FODMAP Diet With Metformin in preDM

An interventional study of High FODMAP diet with metformin and Low FODMAP diet with metformin in PreDiabetes and Impaired Glucose Tolerance, sponsored by Elaine Chow. Completed at 1 site in Hong Kong. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2025-03-05.

Sponsored by Elaine Chow · Not applicable, Interventional, and Prevention

Phase
Not applicable
Study type
Interventional
Enrollment
26
Allocation
Randomized
Ages
18 Years to 70 Years
Sex
All
01

Study summary

This is a prospective, double blinded, randomised cross over feeding trial examine high or low FODMAP diet in combination with metformin on postprandial glucose responses and gastrointestinal tolerability and gut microbiota profiles.

The trial will compare high or low FODMAP diet, each of 10 days duration in combination with 5 days metformin, separated by a washout period of at least 2 weeks.

02

Conditions studied

  • PreDiabetes
  • Impaired Glucose Tolerance
03

In context

Prediabetic State

918 studies on the registry are indexed under Prediabetic State; 232 are open to participants now.

This study's enrollment of 26 is below the median of 62 across 762 interventional studies indexed under Prediabetic State.

Browse Prediabetic State studies →

Lead sponsor

Elaine Chow is the lead sponsor of 7 studies on the registry; 3 are open to participants now.

Counted across the registry records on this site, refreshed daily.

04

Who can participate

Ages eligible
18 Years to 70 Years
Sexes eligible
All
Accepts healthy volunteers
No

Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.

Inclusion criteria

  1. Age 18-70 years
  2. 18 to 40 kg/m 2
  3. 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 5.7-6.4% at screening

Exclusion criteria

Exclusion Criteria:

  1. Currently pregnant, lactating, as demonstrated by a positive pregnancy test at screening or planning pregnancy
  2. Known current diabetes
  3. Current or previous use of glucose-lowering or weight loss drugs in 3 months prior to screening
  4. Concurrent participation in other weight loss or lifestyle intervention programmes
  5. 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.
  6. Recent intake of prebiotic/probiotic or antibiotic, (within 8 weeks of randomisation)
  7. Extensive skin changes/diseases that preclude wearing the FGM on normal skin at the proposed application sites (e.g., extensive psoriasis, recent burns or severe sunburn, extensive eczema, extensive scarring, extensive tattoos, dermatitis herpetiformis).
  8. Known uncontrolled thyrotoxicosis
  9. Known vitamin B deficiency
  10. Known irritable bowel syndrome or gastrointestinal disorders
  11. Estimated (eGFR) \<45 ml/min/1.73m2 at screening
  12. Current use of
  13. Have a known allergy to medical-grade adhesives
  14. Known current or recent alcohol or drug abuse
  15. to metformin
  16. Acute or chronic metabolic acidosis, including diabetic ketoacidosis, with or without coma within 3 months of randomisation
  17. Currently participating in another study protocol where the testing or results may interfere with study compliance, diagnostic results, or data collection.
  18. An identified protected vulnerable patient (including but not limited to those in detention, or a prisoner).
  19. Participants who are on a vegetarian or vegan diet as their habitual diet at screening.
  20. Participants with food allergy to components of the study diet
Terms in these criteria, in plain language(8)

Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.

BMI (body mass index)

Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.

What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.

HbA1c

A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.

Immunosuppression

A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.

Read whether the line is about a condition or about medicines, and which medicines and doses it means.

GFR and eGFR (kidney filtering)

GFR (glomerular filtration rate) is how much blood the kidneys filter each minute. It is usually estimated from a blood test — eGFR, by formulas such as CKD-EPI or MDRD — and some studies ask for it to be measured directly instead. Usually given in mL/min/1.73 m².

Check the method, the units and the minimum the study states. A value of 90 or above is in the normal-or-high range, but kidney damage can show in other tests too.

Corticosteroids (steroids)

Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.

Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.

Hypersensitivity

An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.

Investigational drug or device

A drug or device being studied in a clinical trial.

It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.

Clinically significant

Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.

05

Study design

Phase
Not applicable
Primary purpose
Prevention
Allocation
Randomized
Intervention model
Crossover assignment
Masking
Double (Participant, Outcomes assessor)
Enrollment
26 participants (actual)

Study arms

  • Experimental
    High FODMAP

    Combination Product: High FODMAP diet with metformin

  • Placebo comparator
    LOW FODMAP

    Combination Product: Low FODMAP diet with metformin

Interventions

  • Combination productHigh FODMAP diet with metformin

    Controlled High FODMAP diet (15g/day) from day 1-10, metformin XR 1000mg daily day 6-10 for each treatment period

  • Combination productLow FODMAP diet with metformin

    Controlled low FODMAP diet (3g/day) from day 1-10, metformin XR 1000mg daily day 6-10 for each treatment period

06

What researchers measure

Primary outcomes

  1. Differences in postprandial glycemia

    incremental area under curve on continuous glucose monitoring post meal

    Time frame: 10 days

Secondary outcomes

  1. Glucose response to 75g oral glucose tolerance test

    fasting and postchallenge plasma glucose

    Time frame: 10 days

  2. Insulin response to 75g oral glucose tolerance test

    insulin levels

    Time frame: 10 days

  3. Change in alpha diversity of gut microbiota

    Changes in alpha diversity in gut microbiota

    Time frame: 10 days

  4. Change in beta diversity of gut microbiota

    Changes in beta diversity in gut microbiota

    Time frame: 10 days

  5. Body weight

    Differences in body weight between arms

    Time frame: 10 days

  6. Gastrointestinal symptoms

    Measured on visual analogue scale 1-10 for each item, higher score indicates worse symptoms

    Time frame: 10 days

07

Study locations

1 site
  • Prince of Wales Hospital
    Sha Tin, Hong Kong
08

References and documents

Individual participant data

Plan to share: Undecided

No publications or documents are linked to this record.

09

Timeline

Tracking since Sep 25, 2026
ElapsedEstimatedEstimated, not yet reachedSimilar studies: half by the dot; the band is the middle halfHalf of similar studies reached it by the dot; the band is the middle half, from a quarter to three quarters

Ran from Nov 2022 to primary completion in Aug 2023, 9 months.

Of 378 non-industry interventional studies with no phase under Prediabetic State, half reached primary completion within 25 months of starting (the median), counting those still running; a quarter within 12 and three quarters within 39. This study's 9 months is below that.

Counting every sponsor, half of 424 studies reached it within 23 months; a quarter within 11 and three quarters within 37.

How these figures are worked out, and which studies are left out of them.

Registered
Nov 8, 2022
First posted
Nov 28, 2022
StartActual
Nov 11, 2022
Primary completionActual
Aug 25, 2023
CompletionActual
Oct 15, 2023
Last update
Mar 5, 2025
What these dates mean
Start.
When the first participant enrolled; while estimated, when the study expects to open to recruitment.
Primary completion.
When the last participant was examined or treated to collect data for the study's main question, its primary outcome. A study that stopped early gives the date its data collection stopped.
Completion.
When the last participant's last visit took place, for every outcome, secondary ones and side effects included: the end of the study. Often later than primary completion, sometimes the same day.
Actual and Est.
Actual means the registry says the date has happened. Est. (estimated) is a date the sponsor plans or expects. It can still move, and the sponsor is expected to change it to actual once it has passed.
No changes since tracking began. The registry record was last updated on Mar 5, 2025, before this site started recording changes on Sep 25, 2026. Its history is on ClinicalTrials.gov ↗
10

Registry details

Key details

Study ID
NCT05628584
Lead sponsor
Elaine Chow
Responsible party
Elaine Chow (Clinical Assistant Professor, Chinese University of Hong Kong) — Sponsor-investigator
First posted
Nov 28, 2022
Start date
Nov 11, 2022
Primary completion
Aug 25, 2023
Completion
Oct 15, 2023
Last update
Mar 5, 2025

Oversight

Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
View the source record on ClinicalTrials.gov ↗

Not currently enrolling

This study is completed, as verified in Nov 2022. You cannot join it, but the record below documents what was studied.

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