Healthy AdultNCT07837297
Dietary Fibres on Gut Fermentation
A study testing SCF Alone, SCF and FOS (Single Dose) and SCF and FOS (Split Dose) in people with Healthy Adult, run by University of Bath at 1 site in United Kingdom.
Trial summary
The goal of this clinical trial is to learn if adding a rapidly fermenting fibre to a meal containing a slow fermenting fibre affects gut bacterial fermentation and digestive comfort in healthy adults aged 18 to 85 years. Read more about this study
- Who is it for?
- Ages 18 to 85 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy Adult
- What is being tested?
- SCF Alone, SCF and FOS (Single Dose) and SCF and FOS (Split Dose)
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 26 Aug 2026to 27 Aug 2027
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 85 years
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Healthy males and females, aged between 18 and 85 years at the start of the study.
- Self-reported regular bowel habits, defined as an average frequency of between 3 and 21 bowel movements per week (Mitsuhashi et al., 2018). This weekly average accounts for normal daily fluctuations while ensuring an overall healthy baseline.
- Willing and able to comply with all study protocols, including pre-test dietary restrictions (avoiding highly fermentable foods), a 12-hour overnight fast, and consumption of the prescribed dietary fibre test meals.
- Willing to accurately record gastrointestinal symptoms using the Visual Analogue Scale (VAS) and complete the Bristol Stool Scale (BSS) logs over the specified periods.
- Able to understand the study procedures and provide written informed consent.
Who cannot join
- History or current diagnosis of chronic gastrointestinal diseases or conditions (e.g., Irritable Bowel Syndrome [IBS], Inflammatory Bowel Disease [IBD], coeliac disease, chronic constipation, or history of major gastrointestinal surgery).
- Use of systemic antibiotics, prebiotics, probiotics, or medications known to significantly alter gastrointestinal motility within the 3 months prior to the commencement of, or during the study period.
- Known food allergies or severe intolerances to any ingredients present in the test meals (e.g., soluble corn fibre, fructo-oligosaccharides).
- Females who are currently pregnant, planning to become pregnant during the study period, or lactating.
- Currently following a highly restrictive or extreme diet (e.g., strict ketogenic, extreme high-fibre, or medically prescribed diets) that could significantly confound the baseline gut microbiota or fermentation profile.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United Kingdom1 site, 1 recruiting
- Recruiting
University of Bath
Bath, Somerset, BA2 7AY
Kuan-Yu Lin, +44 7799056885, kyl205@bath.ac.uk
About this study
Official title: Acute Effects of Different Dietary Fibres on Gut Fermentation: A Pilot Study
The goal of this clinical trial is to learn if adding a rapidly fermenting fibre to a meal containing a slow fermenting fibre affects gut bacterial fermentation and digestive comfort in healthy adults aged 18 to 85 years. The main questions it aims to answer are:
- Does the addition of a fast fermenting fibre to a meal containing a slow fermenting fibre change the timing and amount of gas produced by gut bacterial fermentation?
- Does the addition of a fast fermenting fibre as a split dose effectively reduce the digestive discomfort typically caused by consuming a high dose of fibre all at once?
Read more
Researchers will compare the effect of adding fructo-oligosaccharides (FOS) over-and-above a single dietary fibre (soluble corn fibre). They will also compare whether taking FOS either all at once versus splitting it into two smaller doses affects gut bacterial fermentation and digestive comfort.
Participants will:
- Visit the research laboratory for 3 test days, with a 1-week break between visits.
- Avoid certain foods and fast overnight before each test day.
- Eat a test breakfast and lunch containing the dietary fibres in different parts of the meal.
- Provide breath samples every 30 minutes to measure gas produced by gut bacteria.
- Answer survey questions about their digestive comfort every 30 minutes.
- Keep a diary of their bowel movements for 5 days during each test cycle.
Short-chain fatty acids (SCFAs) produced through dietary fibre fermentation are essential for maintaining intestinal barrier integrity and regulating systemic metabolism; however, average daily fibre intake frequently remains below recommended levels. While supplementing with highly fermentable fibres, such as fructo-oligosaccharides (FOS), effectively stimulates beneficial microbial activity in the proximal colon, their rapid breakdown often triggers acute gastrointestinal discomfort, including bloating and flatulence. Conversely, soluble corn fibre (SCF) possesses a highly branched structure that ferments slowly and reaches the distal colon, exhibiting excellent gastrointestinal tolerability but yielding a lower initial peak of SCFA production.
Read the detailed description
This study aims to investigate the effect of rapidly fermenting FOS over-and-above slowly fermenting SCF and whether this supports a "spatio-temporal fermentation profile" spanning the entire colonic tract. By balancing fermentation speeds, this strategy holds the potential to maximise total colonic fermentation yield whilst mitigating the adverse symptoms typically associated with isolated high-dose FOS intake. Furthermore, the study explores a split-dosing regimen as an additional temporal strategy; dividing the FOS intake may limit the peak rate of gas production, preventing it from exceeding the gut's natural gas clearance mechanisms, while ensuring a sustained delivery of fermentable substrates.
To evaluate these physiological dynamics, healthy adult participants will complete a randomised, double-blind, crossover trial comprising three distinct acute testing days, separated by 7-day washout periods. Under strict dietary standardisation and overnight fasting conditions, participants will consume meals containing specific dietary fibres. The acute physiological responses will be continuously monitored via non-invasive breath hydrogen and methane analysis to objectively map fermentation kinetics, alongside regular self-reported assessments of gastrointestinal tolerability throughout the testing window.
- Conditions
- Healthy Adult
- Being tested
- SCF Alone, SCF and FOS (Single Dose), SCF and FOS (Split Dose)
- Keywords
- Dietary Fibre, Fructo-oligosaccharides, Gastrointestinal Tolerability, Short-Chain Fatty Acids, Soluble Corn Fibre
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
SCF AloneDietary supplement
Administration of SCF with breakfast.
SCF and FOS (Single Dose)Dietary supplement
Administration of FOS as a single dose over-and-above SCF with breakfast.
SCF and FOS (Split Dose)Dietary supplement
Administration of FOS at breakfast and at lunch, over-and-above SCF at breakfast.
| Study group | Role | What they receive |
|---|---|---|
| SCF Alone | Active comparator | Participants will consume a standardised breakfast containing SCF in the drink component. Three hours later, they will consume a standardised low-fibre lunch. Receives: Dietary Supplement: SCF Alone |
| Single Combined Dose (SCF + FOS) | Experimental | Participants will consume a standardised breakfast containing SCF in the drink component. They will also consume a meal containing a full dose of FOS. Three hours later, they will consume a standardized low-fibre lunch. Receives: Dietary Supplement: SCF and FOS (Single Dose) |
| Split-Dosed Combination (SCF + FOS) | Experimental | Participants will consume a standardised breakfast containing SCF in the drink component. They will also consume a meal containing half the dose of FOS. Three hours later, they will consume a standardized low-fibre lunch containing the other half of the dose of FOS. Receives: Dietary Supplement: SCF and FOS (Split Dose) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Area Under the Curve (AUC) of Breath Hydrogen and Methane Production
Total colonic fermentation yield is evaluated by measuring breath hydrogen and methane concentrations. Breath samples are collected at 30-minute intervals post-intervention using Omed breath analysers. The total production for both gases is quantified independently by calculating their respective AUC values from the averaged concentration-time profiles.
Measured: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day
Secondary outcomes (4)
Fermentation Kinetic Parameters: Maximum Peak Concentration (Cmax) of Breath Gases
The dynamic temporal characteristics of gut fermentation are evaluated by determining the maximum peak concentration (Cmax) for both breath hydrogen and methane. Data is extracted from continuous breath samples collected using Omed breath analysers.
Measured: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day.
Fermentation Kinetic Parameters: Time to Peak (Tmax) of Breath Gases
The dynamic temporal characteristics of gut fermentation are evaluated by determining the time required to reach this peak concentration (Tmax) for both breath hydrogen and methane. Data is extracted from continuous breath samples collected using Omed breath analysers.
Measured: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day.
Acute Gastrointestinal (GI) Tolerability Composite Score
The incidence and severity of subjective GI symptoms (bloating, abdominal cramping, stomach noises/borborygmi, and flatulence) are rated by participants on a scale from 0 (absent) to 10 (extremely severe). Any bowel movements are logged and converted into a stool score from 0 (normal transit) to 10 (diarrhoea). These are summed to calculate a total composite score ranging from 0 to 50, with higher scores indicating worse GI tolerability.
Measured: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day.
Lower Gastrointestinal Response Assessed by the Bristol Stool Scale (BSS)
Participants monitor and log their daily bowel movement frequency and utilise the Bristol Stool Scale (BSS) to objectively assess stool consistency and appearance. This tracks delayed lower gastrointestinal responses beyond the immediate acute testing window.
Measured: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day.
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted23 Sep 2026
- Study start26 Aug 2026 (estimated)
- Primary completion27 Aug 2027 (estimated)
- Study completion27 Aug 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Healthy AdultStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind
- Who is masked
- Participant, Investigator
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Bath
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Kuan-Yu Lin, University of Bath
- Investigators
- Dylan Thompson, Dr., Principal investigator, University of BathOly Perkin, Dr., Principal investigator, University of Bath
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07837297
- Sponsor's protocol ID
- 16901-21733
- Status last verified
- Sep 2026
- First submitted
- 15 Sep 2026
- Last updated
- 23 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 23 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Acute Effects of Different Dietary Fibres on Gut Fermentation: A Pilot Study
- ClinicalTrials.gov ID
- NCT07837297
- Acronym / sponsor ID
- 16901-21733
- Conditions
- Healthy Adult
- Keywords
- Dietary Fibre, Fructo-oligosaccharides, Gastrointestinal Tolerability, Short-Chain Fatty Acids, Soluble Corn Fibre
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- University of BathUniversity, hospital or other
- Study start
- 26 Aug 2026 (estimated)
- Primary completion
- 27 Aug 2027 (estimated)
- Study completion
- 27 Aug 2027 (estimated)
- First posted
- 23 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to learn if adding a rapidly fermenting fibre to a meal containing a slow fermenting fibre affects gut bacterial fermentation and digestive comfort in healthy adults aged 18 to 85 years. The main questions it aims to answer are:
- Does the addition of a fast fermenting fibre to a meal containing a slow fermenting fibre change the timing and amount of gas produced by gut bacterial fermentation?
- Does the addition of a fast fermenting fibre as a split dose effectively reduce the digestive discomfort typically caused by consuming a high dose of fibre all at once?
Researchers will compare the effect of adding fructo-oligosaccharides (FOS) over-and-above a single dietary fibre (soluble corn fibre). They will also compare whether taking FOS either all at once versus splitting it into two smaller doses affects gut bacterial fermentation and digestive comfort.
Participants will:
- Visit the research laboratory for 3 test days, with a 1-week break between visits.
- Avoid certain foods and fast overnight before each test day.
- Eat a test breakfast and lunch containing the dietary fibres in different parts of the meal.
- Provide breath samples every 30 minutes to measure gas produced by gut bacteria.
- Answer survey questions about their digestive comfort every 30 minutes.
- Keep a diary of their bowel movements for 5 days during each test cycle.
Short-chain fatty acids (SCFAs) produced through dietary fibre fermentation are essential for maintaining intestinal barrier integrity and regulating systemic metabolism; however, average daily fibre intake frequently remains below recommended levels. While supplementing with highly fermentable fibres, such as fructo-oligosaccharides (FOS), effectively stimulates beneficial microbial activity in the proximal colon, their rapid breakdown often triggers acute gastrointestinal discomfort, including bloating and flatulence. Conversely, soluble corn fibre (SCF) possesses a highly branched structure that ferments slowly and reaches the distal colon, exhibiting excellent gastrointestinal tolerability but yielding a lower initial peak of SCFA production.
Detailed description
This study aims to investigate the effect of rapidly fermenting FOS over-and-above slowly fermenting SCF and whether this supports a "spatio-temporal fermentation profile" spanning the entire colonic tract. By balancing fermentation speeds, this strategy holds the potential to maximise total colonic fermentation yield whilst mitigating the adverse symptoms typically associated with isolated high-dose FOS intake. Furthermore, the study explores a split-dosing regimen as an additional temporal strategy; dividing the FOS intake may limit the peak rate of gas production, preventing it from exceeding the gut's natural gas clearance mechanisms, while ensuring a sustained delivery of fermentable substrates.
To evaluate these physiological dynamics, healthy adult participants will complete a randomised, double-blind, crossover trial comprising three distinct acute testing days, separated by 7-day washout periods. Under strict dietary standardisation and overnight fasting conditions, participants will consume meals containing specific dietary fibres. The acute physiological responses will be continuously monitored via non-invasive breath hydrogen and methane analysis to objectively map fermentation kinetics, alongside regular self-reported assessments of gastrointestinal tolerability throughout the testing window.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Double blind (participant, investigator)
- Number of arms
- 3
| Arm | Type | Receives |
|---|---|---|
| SCF Alone | Active comparator | Dietary Supplement: SCF AloneParticipants will consume a standardised breakfast containing SCF in the drink component. Three hours later, they will consume a standardised low-fibre lunch. |
| Single Combined Dose (SCF + FOS) | Experimental | Dietary Supplement: SCF and FOS (Single Dose)Participants will consume a standardised breakfast containing SCF in the drink component. They will also consume a meal containing a full dose of FOS. Three hours later, they will consume a standardized low-fibre lunch. |
| Split-Dosed Combination (SCF + FOS) | Experimental | Dietary Supplement: SCF and FOS (Split Dose)Participants will consume a standardised breakfast containing SCF in the drink component. They will also consume a meal containing half the dose of FOS. Three hours later, they will consume a standardized low-fibre lunch containing the other half of the dose of FOS. |
Who may qualify
- Ages
- 18 to 85 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (5 listed)
- Healthy males and females, aged between 18 and 85 years at the start of the study.
- Self-reported regular bowel habits, defined as an average frequency of between 3 and 21 bowel movements per week (Mitsuhashi et al., 2018). This weekly average accounts for normal daily fluctuations while ensuring an overall healthy baseline.
- Willing and able to comply with all study protocols, including pre-test dietary restrictions (avoiding highly fermentable foods), a 12-hour overnight fast, and consumption of the prescribed dietary fibre test meals.
- Willing to accurately record gastrointestinal symptoms using the Visual Analogue Scale (VAS) and complete the Bristol Stool Scale (BSS) logs over the specified periods.
- Able to understand the study procedures and provide written informed consent.
Key exclusion criteria (5 listed)
- History or current diagnosis of chronic gastrointestinal diseases or conditions (e.g., Irritable Bowel Syndrome [IBS], Inflammatory Bowel Disease [IBD], coeliac disease, chronic constipation, or history of major gastrointestinal surgery).
- Use of systemic antibiotics, prebiotics, probiotics, or medications known to significantly alter gastrointestinal motility within the 3 months prior to the commencement of, or during the study period.
- Known food allergies or severe intolerances to any ingredients present in the test meals (e.g., soluble corn fibre, fructo-oligosaccharides).
- Females who are currently pregnant, planning to become pregnant during the study period, or lactating.
- Currently following a highly restrictive or extreme diet (e.g., strict ketogenic, extreme high-fibre, or medically prescribed diets) that could significantly confound the baseline gut microbiota or fermentation profile.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| SCF AloneAdministration of SCF with breakfast. | Dietary supplement | SCF Alone |
| SCF and FOS (Single Dose)Administration of FOS as a single dose over-and-above SCF with breakfast. | Dietary supplement | Single Combined Dose (SCF + FOS) |
| SCF and FOS (Split Dose)Administration of FOS at breakfast and at lunch, over-and-above SCF at breakfast. | Dietary supplement | Split-Dosed Combination (SCF + FOS) |
Primary outcome
Area Under the Curve (AUC) of Breath Hydrogen and Methane Production
Time frame: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day
Total colonic fermentation yield is evaluated by measuring breath hydrogen and methane concentrations. Breath samples are collected at 30-minute intervals post-intervention using Omed breath analysers. The total production for both gases is quantified independently by calculating their respective AUC values from the averaged concentration-time profiles.
4 secondary outcomes
Fermentation Kinetic Parameters: Maximum Peak Concentration (Cmax) of Breath Gases
Time frame: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day.
Fermentation Kinetic Parameters: Time to Peak (Tmax) of Breath Gases
Time frame: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day.
Acute Gastrointestinal (GI) Tolerability Composite Score
Time frame: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day.
Lower Gastrointestinal Response Assessed by the Bristol Stool Scale (BSS)
Time frame: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day.
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 23 Sep 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Dylan Thompson, Dr. principal investigator
University of Bath
Oly Perkin, Dr. principal investigator
University of Bath
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing SCF Alone, SCF and FOS (Single Dose) and SCF and FOS (Split Dose) in people with Healthy Adult, run by University of Bath at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 5 inclusion and 5 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 23 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Kuan-Yu Lin (+44 7799056885, kyl205@bath.ac.uk), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Area Under the Curve (AUC) of Breath Hydrogen and Methane Production (time frame: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 23 Sep 2026; AzTrials last refreshed its copy on 3 Nov 2026.