Trial Review

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Trial registered on ANZCTR


Registration number
ACTRN12625000630415
Ethics application status
Approved
Date submitted
29/04/2025
Date registered
16/06/2025
Date last updated
10/08/2025
Date data sharing statement initially provided
16/06/2025
Type of registration
Prospectively registered

Titles & IDs
Public title
The impact of dietary fibre and a carbohydrate-fibre-FODMAP gel on gut health and symptoms during exercise.
Scientific title
The impact of pre-exercise dietary fibre intake and during exercise carbohydrate-fibre-FODMAP gel on gastrointestinal integrity, functional responses, and symptoms in response to prolonged exercise in the heat in endurance athletes.
Secondary ID [1] 314211 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
exercise-induced gastrointestinal syndrome 337108 0
Condition category
Condition code
Oral and Gastrointestinal 333527 333527 0 0
Other diseases of the mouth, teeth, oesophagus, digestive system including liver and colon
Diet and Nutrition 334090 334090 0 0
Other diet and nutrition disorders

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Intervention Description (All Trials)
Physical/Informational Materials: Participants will receive written meal plans and food lists tailored to the dietary condition (high fibre, low fibre, carbohydrate supplementation). The kiwiberry gel is provided in pre-measured sachets. A brief guide on how to consume the gel during exercise will also be included. All materials are developed by Accredited Practising Dietitians (APDs).

Procedures and Activities:
Participants will complete the following protocol for each trial:
•Pre-trial diet: 2 days of prescribed dietary intake (either high or low fibre) inclusive of breakfast, lunch, dinner, and snacks.
•Pre-exercise meal: Low fibre (Approximately <1g fibre) breakfast 2 hours before trial.
•Exercise: 2-hour treadmill run at 60% maximal effort in a controlled 35°C lab environment. 1h recovery period prior to completing a 20-minute performance/distance test.
•A trained researcher will perform a 30-minute electrogastrography (EGG) recording both before exercise and again following the 2-hour exercise period. This procedure is used to measure the electrical activity of your stomach. You will be asked to lie down in a supine (face-up) position and remain completely still for the duration of the recording. To ensure accurate results, you will need to remove all metal jewellery and avoid contact with any metal during the procedure. To prepare for electrode placement, three small areas on your abdominal skin will be cleaned and gently abraded with gauze. If necessary, any hair in these areas will be shaved to improve signal quality. A small amount of gel will be applied to each site, and three disposable surface electrodes will then be attached. Electrode leads will be connected to these sensors to capture the readings. This non-invasive procedure will be performed by researchers trained and experienced in EGG data collection.
•Performance test: 20-minute treadmill distance test 30 minutes after EGG.

Intervention / Exposure Description

Trial: High Fibre
•Diet: High fibre intake (Approximately 52 g/day) for 2 days prior to trial (prescribed meals).
•Pre-exercise meal: Low fibre (Approximately <1g fibre) breakfast 2.5 hours before trial.
•Exercise intake: Water only during the 2-hour exertional heat stress protocol.
•Performance test: 20-minute treadmill distance test 30 minutes after EGG.

Trial: Low fibre, Carbohydrate Supplement During Exercise
•Diet: Low fibre intake (Approximately 10 g/day) for 2 days prior to trial (prescribed meals).
•Pre-exercise meal: Low fibre (Approximately <1g fibre) breakfast 2.5 hours before trial.
•Exercise intake: Kiwiberry gel (containing 30g carbohydrate per gel, FODMAPs and fibre), consumed at 0 min and every 20 min during the 2h exertional trial during the 2-hour exertional heat stress protocol.
•Performance test: 20-minute treadmill distance test 30 minutes after EGG.

Mode and Setting of Delivery: In-person at a controlled laboratory setting in a university-based heat chamber and human performance lab. Individual delivery. BASE Facility, Monash University, Exercise Physiology Laboratory, by co-investigator, research students and Chief Investigator.

Frequency, Schedule, Duration:
To complete all aspects of the study, each participant will complete the following:
•One occasion for the initial assessment (approx. 1-1.5 hour).
•3 occasions for the exercise trials (approx. 7 hours each). – each separated by approximately 6-10 days.
•One occasion to provide a faecal sample (approx. 15 mins).
•10 – 15 mins to complete food and exercise diary reporting intake for the 48 hours prior to experimental trial.
•Approximately 60 minutes in total to complete two 2-day estimated food intake diaries of your habitual diet (i.e. one at the start and one later in the study).
Total time required: 24.5 hours

Location: BASE Facility, Monash University, Level 1, 264 Ferntree Gully Road, Notting Hill. Exercise Physiology Laboratory.

Personalisation/Adaptation: The intervention is not personalised or titrated. All participants follow standardised dietary and exercise protocols for consistency and comparability between trials.

Adherence and Fidelity:
Adherence will be assessed through:
•Pre-trial diet logs reviewed by APDs.
•Supplement consumption monitored and recorded during the trial.
•Exercise and test protocol adherence supervised in-lab.

Fidelity strategies include:
•Training sessions for staff conducting assessments.
•Use of standardised instructions and checklists.
•Supervised administration of all trial components.
Intervention code [1] 330821 0
Lifestyle
Intervention code [2] 331246 0
Treatment: Other
Comparator / control treatment
Comparator / Control Description
Trial: Low Fibre – Control Condition
•Diet: Low fibre intake (Approximately 10 g/day) for 2 days prior to trial (prescribed meals).
•Pre-exercise meal: Low fibre breakfast (approximately <1g dietary fibre) 2.5 hours before trial.
•Exercise intake: Water only during the 2-hour exertional heat stress protocol ( 2-hour treadmill run at 60% maximal effort in a controlled 35°C lab environment).
•1h recovery period prior to completing a 20 minute performance/distance test.
•Prior to exercise and post 2h exercise period: A 30-minute electrogastrography (EGG) will be recorded.
•Performance test: 20-minute treadmill distance test 30 minutes after EGG.
Control group
Active

Outcomes
Primary outcome [1] 341115 0
Intestinal fatty acid binding protein (I-FABP)
Timepoint [1] 341115 0
Pre-exercise (before the 2-hour run in the heat), Immediately Post-exercise (after the 2-hour run in the heat) and 1h Post-exercise (after the 2-hour run in the heat) for all trials.
Secondary outcome [1] 446334 0
Soluble cluster of differentiation 14 (sCD14)
Timepoint [1] 446334 0
Pre-exercise (before the 2-hour run in the heat), Immediately Post-exercise (after the 2-hour run in the heat) and 1h Post-exercise (after the 2-hour run in the heat) for all trials.
Secondary outcome [2] 446335 0
Breath samples for H2 content
Timepoint [2] 446335 0
Pre-exercise (before the 2-hour run in the heat), post-exercise periods (after the 2-hour run in the heat and after the 20 minute performance test) - i.e., after 2h run in the heat during the 1h recovery period which is prior to the performance test, every 15 mins and then again after the 20 minute performance test, for 2h recovery period, every 15 mins.
Secondary outcome [3] 446336 0
Gastric slow wave activity
Timepoint [3] 446336 0
Pre-exercise and immediately post-exercise i.e., after 2h exercise trial.
Secondary outcome [4] 446338 0
Gastrointestinal symptoms (GIS)
Timepoint [4] 446338 0
Pre-exercise, every 15 min during 2h exercise, post-exercise every 15 min prior to performance/distance test and then every 15 min after the performance distance test for a 2h recovery period.

Eligibility
Key inclusion criteria
Healthy, active individuals – recreational, competitive or elite runners who are capable of running for 2 hours at moderate intensity (60% of VO2 max i.e., easy long run pace) in the heat (35°C). Aged 18-55 years. Non-heat acclimatised with previous experienced incidence of exercise-associated gastrointestinal symptoms.
Minimum age
18 Years
Maximum age
55 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Participants excluded if they confirm having gastrointestinal infections, diseases, and/or disorders (e.g., coeliac disease, inflammatory bowel disease, irritable bowel syndrome, diverticular disease, gastro-esophageal reflux disease, past history of gastrointestinal surgery, and/or other self-reported gastrointestinal issues), consume potential modifiers of gastrointestinal integrity (such as prebiotics, probiotics, and/or antibiotics), adhering to gastrointestinal focused dietary regimes (such as low FODMAP or fiber-modified diets) within the previous 3 months, consume non-steroidal anti-inflammatory medications and/or stool altering medications (e.g., laxatives and anti-diarrhea) within one month before the experimental protocol. Individuals presenting soft tissues injury 1 month prior to participation due to risk of re-occurence of injury. Smokers. Pregnancy.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
An independent research dietitian will randomise participants into groups using a computer-generated randomisation tool.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software (i.e. computerised sequence generation).
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Other design features
Phase
Not Applicable
Type of endpoint/s
Statistical methods / analysis

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
4/08/2025
Actual
Date of last participant enrolment
Anticipated
15/12/2025
Actual
Date of last data collection
Anticipated
15/12/2025
Actual
Sample size
Target
12
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 318726 0
Other Collaborative groups
Name [1] 318726 0
Be Active Sleep Exercise Facility
Country [1] 318726 0
Australia
Primary sponsor type
Other Collaborative groups
Name
Be Active Sleep Exercise Facility
Address
Country
Australia
Secondary sponsor category [1] 321163 0
None
Name [1] 321163 0
Address [1] 321163 0
Country [1] 321163 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 317341 0
Monash University Human Research Ethics Committee
Ethics committee address [1] 317341 0
Ethics committee country [1] 317341 0
Australia
Date submitted for ethics approval [1] 317341 0
31/03/2025
Approval date [1] 317341 0
12/06/2025
Ethics approval number [1] 317341 0
ID No. 46969

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 140734 0
A/Prof Ricardo Costa
Address 140734 0
Department of Nutrition, Dietetics and Food, Be Active Sleep Eat (BASE) Facility Monash University, Level 1, 264 Ferntree Gully Road, Notting Hill 3168
Country 140734 0
Australia
Phone 140734 0
+61 03 9905 6861
Fax 140734 0
Email 140734 0
[email protected]
Contact person for public queries
Name 140735 0
Dr Stephanie Gaskell
Address 140735 0
Department of Nutrition, Dietetics and Food, Be Active Eat Sleep Facility (BASE), Level 1, 264 Ferntree Gully Road, Notting Hill VIC 3168
Country 140735 0
Australia
Phone 140735 0
+61 0417 122 070
Fax 140735 0
Email 140735 0
[email protected]
Contact person for scientific queries
Name 140736 0
Ricardo Costa
Address 140736 0
Department of Nutrition, Dietetics and Food, Be Active Sleep Eat (BASE) Facility Monash University, Level 1, 264 Ferntree Gully Road, Notting Hill 3168
Country 140736 0
Australia
Phone 140736 0
+61 03 9905 6861
Fax 140736 0
Email 140736 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
No


What supporting documents are/will be available?

TypeCitationLinkEmailOther DetailsAttachment
Informed consent form    2025 consent-form-final dietary fibre .doc
Other    Explanatory Participant Information fibre study.docx


Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.