An interventional study of SCF Alone and SCF and FOS (Single Dose) in Healthy Adult, sponsored by University of Bath. Recruiting at 1 site in United Kingdom. Open to participants aged 18 Years to 85 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-23.
Sponsored by University of Bath · Not applicable, Interventional, and Basic science
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:
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:
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.
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.
University of Bath is the lead sponsor of 94 studies on the registry; 20 are open to participants now.
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Exclusion Criteria:
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.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants will consume a standardised breakfast containing SCF in the drink component. Three hours later, they will consume a standardised low-fibre lunch.
Dietary Supplement: SCF Alone
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.
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 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.
Dietary Supplement: SCF and FOS (Split Dose)
Administration of SCF with breakfast.
Drug page: Fructooligosaccharide
Administration of FOS as a single dose over-and-above SCF with breakfast.
Drug page: Fructooligosaccharide
Administration of FOS at breakfast and at lunch, over-and-above SCF at breakfast.
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.
Time frame: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day
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.
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
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.
Time frame: 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.
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)
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.
Time frame: Baseline (fasting) and every 30 minutes up to 8 hours on each acute test day.
Plan to share: No
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Studies of the drug tested here: Fructooligosaccharide
University of Bath