PRECOG Pilot Project

The Impact of Chronic Consumption of Plant-based Fibres on Cognitive Performance, Gut Microbiome and Mental Health Outcomes in Older Adults: a Pilot Randomised Controlled Trial

This pilot study aims to investigate the chronic effects of a prebiotic blend on cognitive, affective and gut microbiome outcomes in healthy adults aged 60-75 years.

Study Overview

• Status: Completed
• Conditions: Cognition; Gut Microbiome; Affect (Mental Function)
• Intervention / Treatment: Dietary supplement: Prebiotic blend; Dietary supplement: Placebo

Detailed Description

This pilot study will employ a double-blind, randomised, placebo-controlled parallel design to investigate the chronic effects of 12-week-long prebiotic blend consumption on cognitive, affective, gut microbiome, metabolic, and anthropometric outcomes in healthy older adults with mild to moderate subjective cognitive complaints. Fifty participants will be randomised to Intervention or Placebo groups where they will be consuming 10g of prebiotic fibre blend or 10g of placebo (matched placebo powder) per day for 12-weeks. Outcome measures will be acquired before and after a 12-week chronic supplementation. These will include cognitive measures of overall cognitive functioning, and domain-specific cognitive performance, affective measures of depression and anxiety symptomatology; gastrointestinal symptomatology; systolic and diastolic blood pressure, as well as height, weight, hip and waist circumference. In addition, stool samples will be collected at all timepoints to assess microbiome diversity and composition.

• Study Type: Interventional
• Enrollment (Actual): 50
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United Kingdom
  • Berkshire
    • Reading, Berkshire, United Kingdom, RG6 6ES
      • University of Reading, School of Psychology and Clinical Languages

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Aging between 60-75 years old
• Having normal vision and hearing
• Having a normal body mass index (BMI<30)

Exclusion Criteria:

• Having mild to moderate subjective cognitive complaints
• Smoking
• Having food allergies
• Following restrictive and/or unbalanced diets
• Changing dietary intake majorly in past month
• Being diagnosed with any psychiatric or neurologic conditions (e.g. schizophrenia, depression, dementia) including eating disorders
• Being diagnosed with any cardiometabolic diseases (including type II diabetes and cardiovascular disease), or suffering from hypertension or thrombosis related disorders or suffer from thyroid disease
• Currently taking anticoagulants, antiplatelet medication, antidepressants, proton-pump inhibitors
• Currently consuming prebiotic or probiotic supplements
• Continuous antibiotic use for > 3 days within 1 month prior to enrolment
• Continuous use of weight-loss drug for > 1 month before screening
• Having a significant gastrointestinal (GI) condition affecting absorption including (but not limited to) inflammatory bowel disease; total colectomy or bariatric surgery; irritable bowel disease; end stage renal disease; active cancer, or treatment for any cancer, in last 3 years
• Having a high fibre intake defined as > 20g of fibre/day
• Wheat and/or gluten intolerance and having coeliac disease

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Active: prebiotic blend (powder); Subjects will consume 10g of prebiotic fibre powder in their tea/coffee/water at breakfast.	Dietary supplement: Prebiotic blend; 10g of prebiotic fibre blend powder
Placebo Comparator: Active: matched placebo (powder); Subjects will consume 10g of matched placebo powder in their tea/coffee/water at breakfast.	Dietary supplement: Placebo; 10g of matched placebo powder

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Gut microbiome diversity	Stool samples will be collected to measure gut microbiome diversity. Indices of alpha and beta diversity will be analysed (16s sequencing).	From baseline (pre intervention) to week 12 (post intervention)
Gut microbiome composition	Stool samples will be collected to measure gut microbiome composition (genus and species) (16s sequencing).	From baseline (pre intervention) to week 12 (post intervention)
Cognitive Drug Research Computerized Assessment System (COGDRAS) scores	The COGDRAS battery consists of 8 individual cognitive tests testing memory, attention and reaction times.	From baseline (pre intervention) to week 12 (post intervention)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Montreal Cognitive Assessment (MoCA) score	Composite measure of global cognitive function	From baseline (pre intervention) to week 12 (post intervention)
Geriatric Depression Scale scores	A validated self-report measure of depression that includes 15-items.	From baseline (pre intervention) to week 12 (post intervention)
Geriatric Anxiety Inventory scores	A validated self-report measure of anxiety that includes 20-items.	From baseline (pre intervention) to week 12 (post intervention)
Blood Pressure	Systolic and diastolic blood pressure (in mmHg) will be measured.	From baseline (pre intervention) to week 12 (post intervention)
Hip and waist circumference	Hip and waist circumference (in cm) will be measured.	From baseline (pre intervention) to week 12 (post intervention)
Gastrointestinal Symptom Rating Scale Scores	A validated self-report measure of gastrointestinal symptoms that includes 15-items (combined into five symptom clusters depicting Reflux, Abdominal pain, Indigestion, Diarrhoea and Constipation) .	From baseline (pre intervention) to week 12 (post intervention)
Positive and Negative Affect Schedule (PANAS)	A 20-item questionnaire measuring positive and negative affect.	From baseline (pre intervention) to week 12 (post intervention)
Body Mass Index	Weight (in kg) and height (in m) will be combined to report BMI in kg/m^2.	From baseline (pre intervention) to week 12 (post intervention)

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Telephone Interview for Cognitive Status-40	A questionnaire that assesses cognitive status. It will be used to screen participants. Only individuals who score between 6 and 20 (depicting mild to moderate subjective cognitive complaints) will be included in the study.	Baseline (pre intervention)
FiberScreen Scores	A questionnaire that assesses fibre intake. It will be used to screen participants. Individuals who adhere to a high fibre diet (>20g fibre/day) will be excluded from the study.	Baseline (pre intervention)
EPIC Norfolk Food Frequency Questionnaire (FFQ)	The FFQ is a validated tool for gauging the average habitual dietary intake of micro and macronutrients of an individual in the UK. Data will be processed using the FETA software.	Baseline (pre intervention)

Collaborators and Investigators

• Sponsor: University of Reading
• Collaborators: Biotechnology and Biological Sciences Research Council; Myota Limited; i-NutriLife Hub

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2025
• Primary Completion (Actual): December 1, 2025
• Study Completion (Actual): December 1, 2025

Study Registration Dates

• First Submitted: March 20, 2025
• First Submitted That Met QC Criteria: March 27, 2025
• First Posted (Actual): April 4, 2025

Study Record Updates

• Last Update Posted (Estimated): December 3, 2025
• Last Update Submitted That Met QC Criteria: December 2, 2025
• Last Verified: December 1, 2025

More Information

Terms related to this study

• Keywords: depression; cognition; anxiety; prebiotics; gut microbiome diversity; relative abundance
• Additional Relevant MeSH Terms: Mental Disorders; Behavioral Symptoms; Behavior; Anxiety Disorders; Depression
• Other Study ID Numbers: UREC 25/03

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No