Gut Microbial Metabolites of Apple Polyphenols

Study Overview
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Brief Summary
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The goal of this controlled feeding trial is to learn about the metabolism of polyphenols, a common class of compounds found in plant-based foods, by the gut microbiome. It will evaluate how differences in gut bacteria across individuals influence metabolism of polyphenols from foods, which may influence health benefits that people receive from different foods.

Detailed Description
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This is a randomized, cross-over controlled feeding trial. Thirty healthy adult volunteers will be selected to participate on the basis of urinary screening results measuring a gut bacterial metabolite that is produced following consumption of a soy food: 15 O-desmethylangolensin (ODMA) producers and 15 age and gender-matched ODMA non-producers will be included. Participants will be assigned to consume two diets in random order: an apple catechin diet that provides a controlled amount of catechins in apple juice, and a nutritionally-matched low catechin diet. Both diet phases will last 3 days, with a 10 day washout period in between the two diet phases.

Official Title
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Gut Microbial Metabolites Of Apple Polyphenols: Interrogating Individual Differences To Establish Functional Biomarker Utility

Conditions
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Healthy, Controlled Feeding Trial

Intervention / Treatment
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* Other: Dietary intervention - apple catechin diet
* Other: Dietary intervention - low catechin diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Completion of informed consent. Stated willingness to comply with all study procedures and availability for the duration of the study. Any gender identification, aged 18 - 45. BMI 18.5 - 40 kg/m^2 Ability to consume the intervention foods and beverages and be willing to adhere to the dietary regimen. Agreement to provide urine and fecal samples according to the study protocol. Agreement to adhere to avoid high catechin foods (tea, chocolate) for 4 weeks. Able to come to the study location for 8 visits according to the study schedule. As assessed through an initial urine screening phase, a person is eligible either on the basis of (1) the presence of a urinary marker for soy isoflavone metabolism (ODMA), or (2) as a control matched for age and gender. Exclusion Criteria: Current, regular use of antacids or acid reducers. Systemic antibiotic use within the past month prior to the urinary screening until completion of the dietary intervention. Pregnancy or lactation, within 3 months post-partum (regardless of breastfeeding) at screening or planning to become pregnant during the study duration. Known allergic reactions to components of the foods or beverages of the study diet (soy, wheat, dairy, peanut, tree nuts, apples, eggs) or any history of anaphylactic food allergy. Current diagnosis of renal, hepatic, or gastrointestinal conditions. History of stroke. Underweight (BMI <18.5 kg/m^2) or severe obesity (BMI >40 kg/m^2). Under 18 years or above 45 years of age. Unwilling or unable to participate in the controlled dietary intervention or provide urine or fecal samples. Has a pacemaker, implanted defibrillator, or other implanted electronic device. Change of body weight >10% between screening and dietary intervention.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Apple catechin<br>A 3-day controlled diet | Other: Dietary intervention - apple catechin diet<br>* The intervention will provide a catechin-containing apple juice, for consumption alongside a low catechin diet tailored to participants calorie needs for weight maintenance.<br>|
| Placebo Comparator: Low catechin<br>A 3-day controlled diet | Other: Dietary intervention - low catechin diet<br>* The intervention will provide a nutritionally-matched beverage without catechins, for consumption alongside a low catechin diet tailored to participants calorie needs for weight maintenance.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean sum catechin metabolites | Mean difference in sum catechin metabolite concentration in response to the intervention, stratified by ODMA producers and non-producers. | Post 3-day intervention vs. post 3-day control | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean individual catechin metabolites | Mean differences in individual valerolactone and valeric acid concentrations in response to the intervention, stratified by ODMA producers and non-producers. | Post 3-day intervention vs. post 3-day control | 
| Differences in microbiome profiles | Differences in microbiome profiles in response to the 3-day intervention. | Post 3-day intervention vs. post 3-day control | 
| Difference in microbiome diversity | Differences in microbiome diversity in response to the 3-day intervention. | Post 3-day intervention vs. post 3-day control | 
| Difference in microbial species abundance | Differences in microbial species abundance in response to the 3-day intervention. | Post 3-day intervention vs. post 3-day control | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gut microbiome, Flavonoids, Isoflavones, Catechin