The Impact of Food on Gut Microbiome Composition - a Clinical Trial Determining the Influence of Diet in Gut Microbiome Colonisation and Host Health

Early Phase 1CompletedNCT05986955

Monash University25 enrolled

Overview

The goal of this clinical trial is to examine the impact of food derived bacteria on gut microbiome composition and host health. The main questions it aims to answer are: * what is the the rate of gastrointestinal colonisation of food derived bacteria? * what is the contribution of food derived bacteria to gut microbiome stability? Participants will complete a cross over feeding study of dietitian designed meals of known microbial load and will be asked to provide stool and blood samples for analysis.

To understand the role and stability of food derived bacteria in impacting microbiome composition, 20 healthy participants will be recruited for this single site double blinded randomised controlled crossover pilot trial. The study is divided into four 14 day diet phases - baseline habitual, specified diet 1, habitual washout and specified diet 2. Participants will be randomly assigned to receive a microbial or non-microbial diet in specified diet 1 phase. Each participant will then crossover to receive the alternative diet in the specified diet 2 phase. The microbial and non-microbial diets will be identical except for the removal of naturally occurring food derived bacteria in non-microbial diet. At the commencement of the study and at the end of each diet phase, participants will attend a research clinic to undergo comprehensive clinical and anthropometric assessment and dietary evaluation.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

OTHER

Masking

QUADRUPLE

Enrollment

Conditions

Healthy

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Have no genetic conditions (e.g. Prader Willi or Down's Syndrome) * Not diagnosed with a significant medical conditions (e.g. irritable bowel syndrome, inflammatory bowel disease or type 1/2 diabetes) * Do not require drug-therapy (e.g. steroids or insulin or antibiotics) * Not taking dietary supplements, probiotics, prebiotics, symbiotics or fibre supplementation * Any condition that will affect participation in the study * Not pregnant, planning a pregnancy or breastfeeding * Able to complete a two-month dietary study and agree to eating all meals provided * Have no dietary allergies or dietary restrictions that prevent consumption of provided study meals * Open bowels regularly - mostly daily * Able to read, write and understand English Exclusion Criteria: * Dietary concerns identified by dietitian * Aged less than 18 years and older than 65 years * Diagnosed with a medical condition that requires drug therapy * Taking medications or supplements known to alter gastrointestinal microbiota * Women who are pregnant, planning a pregnancy or breastfeeding * Anyone with a diagnosed gastrointestinal condition/disease e.g. irritable bowel syndrome or inflammatory bowel disease * Known dietary allergy and/or intolerance, follows a vegan or vegetarian diet, or has coeliac disease * Anyone with a preference for specific food avoidance or exclusion of certain ingredients in habitual diet * Unable to tolerate blood collection procedures * Unable to provide regular stool samples throughout the study

Outcomes

Primary Outcomes

Characterisation of gut microbiome

Sequencing and bacterial culturing of stool samples

Time frame: Day 1, 4, 7, 11 and 14 of each phase

Secondary Outcomes

Participant body mass index (BMI)

Assessed independently using height and weight measurements and appropriate formula

Time frame: BMI will be calculated on day 14 (at end of each diet phase (fortnightly))

Participant standing height

Measured by stadiometer

Time frame: Height will be measured on day 14 (at end of each diet phase (fortnightly))

Participant weight

Measured using balance scales

Time frame: Weight will be measured on day 14 (at end of each diet phase (fortnightly))

Participant waist circumference

Measured using standard measuring tape

Time frame: Baseline day 1 and end of each 14-day diet phase

Participant Hip circumference

Measured using standard measuring tape

Time frame: Baseline day 1 and end of each 14-day diet phase

Resting systolic and diastolic blood pressure

Measured using digital blood pressure monitor

Time frame: Blood pressure will be measured on day 14 (at end of each diet phase (fortnightly))

Mental Health Assessment

Perceived Stress Scale survey completed by participants

Time frame: Completed at day 1 and end of study (day 56)

Dietary compliance

Measured by participant completed daily diet checklist noting the amount of food they consumed of provided meals during specific diet 1 and 2 phases

Time frame: Day 1 to Day 14 of specified diet 1 and diet 2 phases

Habitual dietary intake

Using research food diary mobile phone application

Time frame: Daily throughout 14-day baseline habitual and habitual washout phases

Changes in physical activity levels

Using International Physical Activity Questionnaire - Short Form (IPAQ-SF)

Time frame: Completed at each of each 14-day diet phase

Glucose levels

Blood samples collected will be assessed for glucose levels

Time frame: Blood collected at baseline day 1 and day 14 of each phase (fortnightly)

Lipid studies

Blood samples collected will be assessed for lipid studies

Time frame: Blood collected at baseline day 1 and day 14 of each phase (fortnightly)

Irritable Bowel Syndrome-Severity Scoring System (IBS-SS)

Completion of Irritable Bowel Syndrome-Severity Scoring System (IBS-SS)

Time frame: End of each 14-day diet phase

Gastrointestinal symptomatology

Completion of Gastrointestinal Symptom Rating Scale (GSRS)

Time frame: Baseline day 1 and day 14 of each diet phase (fortnightly)

Bowel movement

Completion of Bristol Stool Chart questionnaires

Time frame: Baseline day 1 and day 14 of each diet phase (fortnightly)

End of study optional semi-structured interview

Interview participants to assess challenges of adhering to study and compliance

Time frame: End of study (at least 8 weeks post-randomisation)