Investigating how diet affects the gut-brain connection

An Interventional Study on the Association Between Diet, Cognitive Function, Stress and the Gut Microbiota in Healthy Volunteers.

Not applicable Interventional University College Cork · NCT05931562

This study is trying to see if changing the diets of healthy adults with low fiber intake can improve their thinking, stress levels, and gut health over eight weeks.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment200 (estimated)
Ages18 Years to 50 Years
SexAll
SponsorUniversity College Cork Academic / other
Locations1 site (Cork)
Trial IDNCT05931562 on ClinicalTrials.gov

What this trial studies

This study explores the impact of an 8-week dietary intervention on cognitive function, stress levels, and gut microbiota in healthy adults with low fibre intake. Utilizing a randomized-controlled, parallel, single-blinded design, 200 participants will be assigned to one of four dietary groups: high fibre, fermented foods, a combined diet, or a control group. The research aims to understand how different dietary components influence the microbiota-gut-brain axis and overall mental health. By examining the effects of dietary fibre and fermented foods, the study seeks to uncover potential links between nutrition and cognitive health.

Who should consider this trial

Good fit: Ideal candidates are healthy adults aged 18 to 50 with a body mass index between 18.5 and 29.9 who consume a low fibre diet.

Not a fit: Patients with significant acute or chronic illnesses, psychiatric disorders, or those outside the specified age and BMI range may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide insights into dietary modifications that enhance cognitive function and mental well-being.

How similar studies have performed: While the gut-microbiota-brain axis has been studied, this specific approach examining the combined effects of fermented and fibrous foods is novel and has not been extensively tested.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Be able to give written informed consent.
* Be between 18 and 50 years of age.
* Have a body mass index (BMI) between 18.5-29.9 Kg/m2.
* Be in generally good health as determined by the investigator.

Exclusion Criteria:

* Are less than 18 and greater than 50 years of age.
* Have a BMI below 18.5 or above 29.9 Kg/m2.
* Have a significant acute or chronic coexisting illness \[cardiovascular, gastrointestinal (GI) \[to include functional GI disorders, inflammatory bowel disease, coeliac disease, lactose intolerance, food allergies\], immunological, psychiatric \[to include formal or as determined by MINI Psychiatric interview, diagnosis of current major depression, anxiety disorder, bipolar spectrum disorder, schizophrenia, other DSM-IV Axis I disorder\], neurodevelopmental disorders, immunological, metabolic disorders \[to include type I or II diabetes\], or any condition which contraindicates, in the investigators judgement, entry to the study,
* Have a condition or taking a medication that the investigator believes would interfere with the objectives of the study, pose a safety risk, or confound the interpretation of the study results; all psychoactive medications \[to include anxiolytics, antipsychotics, antidepressants, anticonvulsants, centrally acting corticosteroids, and opioid pain relievers), laxatives, enemas, antibiotics, anti-coagulants, over-the counter non-steroidal anti-inflammatories (NSAIDS). Subjects should have a wash-out period of 4 weeks.
* Current prebiotic or probiotic supplement use (a wash-out period of 4 weeks after cessation will allow entry to the study).
* Females who are peri-menopausal, menopausal or post-menopausal.
* Females who are pregnant or planning a pregnancy, or lactating.
* Participants who are not fluent in English.
* Are colour blind.
* Have dyslexia or dyscalculia.
* Are a current habitual daily smoker.
* Individuals who, in the opinion of the investigator, are considered to be poor attendees or unlikely for any reason to be able to comply with the trial.
* Subjects receiving treatment involving experimental drugs. If the subject has been in a recent experimental trial, these must have been completed not less than 30 days prior to this study.
* Have a malignant disease or any concomitant end-stage organ disease.
* Have completed a study in our laboratory in the past 4 years.

Where this trial is running

Cork

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 HealthyMicrobiota-gut-brain axisDietCognitionStressDietary FibreFermented foods
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.