DIAMOND: DIetary plAnt Extracts, Colonic MicrObes, and Apoe geNetics Interactions stuDy

University of East Anglia (Other)
Overall Status
Not yet recruiting
CT.gov ID
Quadram Institute Bioscience (Other)

Study Details

Study Description

Brief Summary

This study will involve donating a salivary sample and a faecal (stool) sample. These will be analysed in the laboratory to determine the forms of the APOE gene you are carrying (your APOE genotype) and the response of the bacteria in your colon to reactive compounds extracted from edible plants (dietary bioactives).

Condition or Disease Intervention/Treatment Phase

    Detailed Description

    In an ageing population, the incidence of dementia is rapidly increasing and poses a significant financial, societal, and above all, personal burden. Aside from ageing, the type of APOE gene an individual carries (their APOE genotype) is the greatest risk factor for the development of cognitive decline. It has been shown that the APOE genotype of an individual influences the types of bacteria present in the colon. The bacteria which reside in the colon have recently emerged as a significant contributor to nutrition and health and have been suggested to influence brain functioning through complex connections between the gut and the brain.

    Nutrition is considered important for brain function throughout life, and findings from recent laboratory and human observational studies have suggested that reactive compounds extracted from edible plants (dietary bioactives) can not only improve brain function, but they can change the function and composition of gut bacteria. Dietary bioactives are a range of natural compounds found in great concentrations within fruits and vegetables which influence the body. An example of a dietary bioactive is a group of compounds known as polyphenols. These polyphenols are described as antioxidants and are found in various foods, including berries, tea, and cocoa.

    There have been no previous studies looking at the impact of dietary bioactives on the microbiome of each APOE genotype and the metabolites produced by each of these bacteria. We aim with the current study to identify how dietary bioactives from a range of plant tissue could influence gut bacteria present and the metabolites produced by the bacteria in each APOE group, and the compounds produced by these bacteria.

    What will the study involve? Once we have established a potentially suitable participant, they will be sent a salivary sampling kit. Depending on the genotype, age and sex, participants will be requested to donate a stool sample. The stool will be processed in a colon model with cocoa polyphenol added.

    The study involves the following stages:
    1. Online screening, consenting, and collection of basic information

    2. Collection of a salivary sample in person at the Clinical Research Facility or home and return to the labs via pre-paid postal mail.

    3. Confirmation of eligibility to donate stool samples.

    4. Collection of stool samples on the same day as sample collection. Returning the sample in person or through the pre-paid postal system.

    Study Design

    Study Type:
    Anticipated Enrollment :
    64 participants
    Observational Model:
    Time Perspective:
    Official Title:
    DIetary plAnt Extracts, Colonic MicrObes, and Apoe geNetics Interactions stuDy
    Anticipated Study Start Date :
    Jul 1, 2023
    Anticipated Primary Completion Date :
    Jan 1, 2025
    Anticipated Study Completion Date :
    Sep 1, 2025

    Arms and Interventions

    Arm Intervention/Treatment
    Prospectively genotyped participants

    These participants will be advertised to in the local area. They will be genotyped for their APOE genotype, and then the stool sample will be collected.

    Database participants

    Participants from the previously genotyped cohort "Early sleep and circadian markers of Alzheimer's disease: the impact of APOE-ε4 on circadian rhythm and sleep-wake homeostasis in humans" (Reference: 2017/18-135) who have consented to be contacted will be contacted to collect a stool sample.

    Outcome Measures

    Primary Outcome Measures

    1. Whether there is a significant difference between the in vitro metabolism of flavan-3-ols using a human colon model [09/2025]

      Participants will be genotyped for their APOE genotype. They will then be requested to donate a stool sample. This stool sample will be run through a colon.model inoculated with flavan-3-ols to determine whether there is a significant difference between the genotypes. Flavan-3-ol metabolism will be measured with LCMS

    2. Determine whether there are significant differences between the composition of the gut microbiome of each APOE genotype. [09/2025]

      Participants will be genotyped for their APOE genotype. Their stool sample will then have its gut microbiome analysed. Metagenomic techniques will be utilised to analyse the microbiome

    Eligibility Criteria


    Ages Eligible for Study:
    18 Years and Older
    Sexes Eligible for Study:
    Accepts Healthy Volunteers:
    Inclusion Criteria:
    • Aged between 18-35 years old or aged 55+ years old

    • Fluent in written and spoken English and capacity to consent

    • Availability to take part in the study

    Exclusion Criteria:
    • Participants will be excluded from donating if they have been diagnosed with any gastrointestinal conditions such as inflammatory bowel disease.

    • They will also be excluded if they have a diagnosis of any form of dementia or severe cognitive impairment.

    • They currently consume a high flavonoid intake defined as >15 portions of flavonoid rich food per day.

    • History or MRI evidence of brain damage, including significant trauma, stroke, learning difficulties or serious neurological disorder, including a loss of consciousness for more than 24 hours.

    • Currently smoking or ceased smoking less than 6 months ago.

    • Chronic fatigue syndrome, liver disease, diabetes mellitus, or gall bladder abnormalities.

    • History of alcohol or drug dependency.

    • Clinically diagnosed psychiatric disorder.

    • Currently a participant or have been a participant in any other study involving an investigational product within the last 4 weeks.

    • Received a COVID-19 diagnosis within the last 30 days

    Contacts and Locations


    Site City State Country Postal Code
    1 Norwich and Norfolk University Hospital Clinical Research Facility Norwich Norfolk United Kingdom NR4 7UY

    Sponsors and Collaborators

    • University of East Anglia
    • Quadram Institute Bioscience


    • Principal Investigator: David Vauzour, PhD, University of East Anglia

    Study Documents (Full-Text)

    None provided.

    More Information


    Responsible Party:
    University of East Anglia
    ClinicalTrials.gov Identifier:
    Other Study ID Numbers:
    • 319832
    First Posted:
    Jun 15, 2023
    Last Update Posted:
    Jun 18, 2023
    Last Verified:
    Apr 1, 2023
    Individual Participant Data (IPD) Sharing Statement:
    Plan to Share IPD:
    Studies a U.S. FDA-regulated Drug Product:
    Studies a U.S. FDA-regulated Device Product:
    Keywords provided by University of East Anglia
    Additional relevant MeSH terms:

    Study Results

    No Results Posted as of Jun 18, 2023