Investigating how dietary fiber affects gut health in older adults

Exploring Mechanism of Action of Dietary Fibre on the Gut Microbiota and Metabolites: Can we Identify Responders and Non-responders to Psyllium and Inulin Dietary Fibres?

Not applicable Interventional University of Aberdeen · NCT05906589

This study is testing whether adding different types of dietary fiber can improve gut health and reduce side effects like diarrhea in healthy older adults.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment42 (estimated)
Ages60 Years and up
SexAll
SponsorUniversity of Aberdeen Academic / other
Drugs / interventionsradiation, chemotherapy, immunotherapy
Locations1 site (Aberdeen)
Trial IDNCT05906589 on ClinicalTrials.gov

What this trial studies

This study examines the effects of dietary fiber, specifically psyllium and inulin, on gut microbiota and metabolites in healthy older adults over 60 years old. Participants will undergo a diet intervention where they will receive either a placebo, inulin, or psyllium to assess their physiological responses. The research aims to understand how dietary fiber can potentially mitigate side effects in cancer patients undergoing pelvic radiotherapy, particularly focusing on diarrhea and gut health. By identifying responders to dietary fiber manipulation, the study seeks to provide insights into improving treatment outcomes for patients with pelvic malignancies.

Who should consider this trial

Good fit: Ideal candidates for this study are healthy adults aged over 60 who do not have significant gastrointestinal or metabolic disorders.

Not a fit: Patients with chronic gastrointestinal conditions or those on specific medications that affect gut health may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could lead to improved management of gastrointestinal side effects in cancer patients receiving pelvic radiotherapy.

How similar studies have performed: While there is evidence from animal studies suggesting dietary fiber can improve treatment outcomes, this specific approach in humans is novel and has not been extensively tested.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* \>60 years old

Exclusion Criteria:

Medication exclusion criteria:

* Oral antibiotic use (within the past 3 months due to impact on gut microbiota).
* Anti-coagulants (Warfarin).
* Carbamazepine (epilepsy)
* Digoxin (heart conditions)
* Mesalazine (gut problems)
* Regular use of anti-constipation medication/laxatives.

Medical exclusion criteria:

* Food allergies, self-reported food sensitivity or intolerance.
* Type 1 or Type 2 diabetes.
* Coeliac disease or gluten intolerance.
* Metformin intake.
* Bowel obstruction
* Muscle weakness of the bowel
* Phenylketonuria.

Other exclusion criteria:

* Anyone with unsuitable veins for blood sampling.
* Anyone with chronic constipation (\>3 days without defaecation).
* Anyone who is unable to fluently speak, read and understand English.

Where this trial is running

Aberdeen

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions PsylliumInulinDietary fibreDietary fiberGut microbiota
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.