Dietary Fibres on Gut Fermentation
Acute Effects of Different Dietary Fibres on Gut Fermentation: A Pilot Study
- Healthy Adult
At a glance
- Phase
- Phase not stated
- Study type
- Interventional
- Sponsor
- University of Bath
- Enrolment target
- 20
- Started
- 26 August 2026
- Main results due
- 27 August 2027
- Study sites
- 1
- Registry updated
- 23 September 2026
Can you take part?
- Ages 18 years to 85 years.
- Open to any sex.
- Healthy volunteers can take part.
These are the headline rules only. Every study has a longer list, and whether you are eligible is decided by the research team at the site — never by this page.
Read the full eligibility criteria
Inclusion Criteria: * 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. Exclusion Criteria: * 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.
What this study is about
In the sponsor’s own words, from the registry.
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.
Study sites(1)
University of Bath
Bath, Somerset, United Kingdom
Recruiting
Showing 1 of 1 sites. 1 of the 1 site on this study is recruiting right now — a site can stop enrolling while the study as a whole is still open.
Source: ClinicalTrials.gov record NCT07837297. Trialion does not run this study, is not paid to refer anyone to it, and cannot enrol you. Eligibility is always decided by the research team at the site.
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