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NCT Number: NCT06765369

How the Mediterranean Diet Affects You: Predicting Responses Based on Your Microbiome

People respond differently to various diets-some may see significant benefits, while others may not. This project aims to personalize dietary recommendations by analyzing the gut microbiome to predict who will benefit most from the Mediterranean diet based on their unique biology, including their microbiome.

The study focuses on answering these key questions:

1. Are there specific microbes that influence who is most likely to benefit from the Mediterranean diet? 2. What changes occur in the gut microbiome when healthy individuals follow a Mediterranean diet?

To explore these questions, researchers will compare the effects of a Mediterranean diet to a Western-style diet. Participants will receive all their meals and snacks for the study to ensure accurate comparisons of how these diets impact the gut microbiome.

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Key information

Conditions

Healthy

Age range

20 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of British Columbia-Okanagan

Kelowna, British Columbia, V1V 1V7, Canada

About this study

Understanding the role of therapeutic dietary interventions in treating chronic diseases requires acknowledging that the response to nutrition varies in populations, subgroups and individual's. Varying responses to dietary intervention is dependent on interpersonal differences and environment. Personalized nutrition addresses these differences between individuals to maximize the benefits of dietary interventions. Many large, randomized controlled trials have effectively demonstrated that only 40% of a study cohort responds to dietary interventions, and lifestyle measures in regards to reducing disease risk. A more pragmatic approach to enhance the effectiveness of dietary treatment emerges by identifying microbiome-derived biomarkers capable of predicting and categorizing those most likely to benefit from specific nutritional interventions. Developing a predictive microbiome signature represents an advancement in this endeavour, offering the prospect of tailored, personalized nutrition interventions and a comprehensive understanding of the intricate interplay between diet, gut microbiota composition, and human health. Specifically, the Mediterranean diet (MD) has been investigated as a therapeutic diet for varying diseases due to its positive correlation with an array of health benefits. However, there is little consensus on specific microbial changes associated with the MD and how the MD alters the gut microbiome. This study aims to fill this knowledge gap that exists surrounding the MD and to determine a predictive microbiome associated with the MD. Ultimately producing a highly predictive microbiome signature that will have the ability to identifies those who will respond to the MD.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Healthy participants, defined as free from cardiovascular disease, diabetes, and hypertension
  • Body Mass Index of 20-25
  • Between the ages 20-50 years
  • Low adherence to the Mediterranean diet (MD serving score [MDSS] less than 10 points).
  • Must live in the Okanagan area

Exclusion criteria

  • Individuals with a self-reported history of irritable bowel syndrome, inflammatory bowel disease, Type-2 diabetes, kidney disease, intestinal obstruction, infectious gastroenteritis, colitis or gastritis, Clostridium difficile infection (recurrent) or Helicobacter pylori infection (untreated), malabsorption (such as celiac disease), major surgery of the GI tract, or colorectal cancer
  • Oral antibiotics within three months of the intervention start date
  • Individuals with any known food allergies, reported dietary intolerances of any kind, and those with eating disorders
  • Pregnant or breastfeeding
  • Participants with a high MDSS (> 10 points)
  • Individuals who are intermittent fasting or refuse to follow the study protocol

Treatment and study plan

Mediterranean Diet

Other

The MD is characterized by increased consumption of legumes, whole grains, vegetables, fruits, nuts, seeds and olive oil, moderate consumption of fish, poultry and dairy foods, with low consumption of processed foods and red meat. The nutritional profile of the MD intervention will consist of 46% carbohydrates, 17% protein, and 35% fat. A significant focus on dietary fat consumption with maintaining an omega 6:3 ratio of approximately 3:1 or lower. The MD will provide fibre-rich foods to meet the fibre recommendations for Canadians (males: 30 grams/day, females: 21 grams/day)

Westernized Diet

Other

The WD is characterized by increased consumption of highly processed foods, refined grains, red meats, processed meats, added sugars, added salt, high intake of omega-6 PUFA, accompanied by a reduction in fibre, fruits and vegetables, whole grains, fish, as well as nuts and seeds.The nutrition composition of the WD intervention will consist of 46% of calories derived from refined carbohydrates and added sugars, 17% protein (sourced from red and processed meats) and 35% fat. The fatty acid profile will be characterized by higher amounts of n-6 PUFAs while lacking in n-3 PUFAs and MUFAs, with a omega 6:3 ratio of 15-20:1.

Primary outcomes

  1. Microbiome - Microbial Diversity

    Time frame: Baseline, Week 3, Week 9 and Week 12

    Metagenomic sequencing will be employed to analyze stool samples, focusing on changes in the taxonomic composition of the gut microbiome in healthy individuals in response to interventions with the Mediterranean and Western diets.

  2. Microbiome - Microbial Signature

    Time frame: Baseline, Week 3, Week 9 and Week 12

    Metagenomic sequencing will be utilized to analyze stool samples, aiming to identify microbial signatures of the gut microbiome in healthy individuals following interventions with the Mediterranean and Western diets.

Secondary outcomes

  1. Metabolomics - Change in fecal metabolites

    Time frame: Baseline, Week 3, Week 9 and Week 12

    Fecal metabolites will be analyzed using a untargeted metabolomic platform with samples collected pre and post MD and Western diet. Quantification will be performed using untargeted reverse-phase ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS).

  2. Metabolomics - Change in serum metabolites

    Time frame: Baseline, Week 3, Week 9 and Week 12

    Serum metabolites will be analyzed using a untargeted metabolomic platform with samples collected pre and post MD and Western diet. Quantification will be performed using untargeted reverse-phase ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS).

  3. Change in Quality of Life

    Time frame: Baseline, Week 3, Week 9, Week 12

    Health-related quality of life will be measured using the 12-item short form-12 (SF-12). The SF-12 is comprised of two components: physical health and mental health. Scores range from 0 to 100, where a zero score indicates the lowest level of health and 100 indicates the highest level of health.

  4. Dietary intake

    Time frame: Baseline, Week 9

    Dietary intake and supplement use will be evaluated at both baseline and week 9 using two non-consecutive 24-hour food recalls collected through the ASA-24 Canadian version. These assessments will establish participants' habitual dietary patterns and help monitor dietary consistency during the washout period.

  5. Appetite rating

    Time frame: The Visual Analog Scales (VAS) for Appetite will be completed daily throughout the dietary intervention period, which includes 3 weeks on the Mediterranean diet and 3 weeks on the Western diet.

    Visual Analog Scales (VAS) for Appetite will be used to assess appetite of healthy participants in response to interventions with Mediterranean and Western diets. Higher values typically indicate greater intensity of the sensation being measured.

  6. Change in Anxiety

    Time frame: Baseline, Week 3, Week 9 and Week 12

    Anxiety will be assessed by the GAD-7 (Generalized Anxiety Disorder-7). It is a self-reported screening tool used to measure the severity of generalized anxiety disorder (GAD) symptoms over the past two weeks. The total score ranges from 0 to 21. A score of 10 or higher typically indicates clinically significant anxiety and suggests the need for further evaluation or intervention..

  7. Change in Depression

    Time frame: Baseline, Week 3, Week 9 and Week 12

    Depression levels will be assessed by PHQ-8 (Patient Health Questionnaire-8). It is a widely used self-report screening tool for assessing the severity of depressive symptoms over the past two weeks. The total score is the sum of all item responses, ranging from 0 to 24. A score of 10 or higher indicates the presence of clinically significant depressive symptoms and suggests the need for further evaluation or intervention.

Study contacts

Contact information is provided by the study sponsor or research team.

Maitreyi Raman, MD

CONTACT

[email protected]

403-592-5020

Natasha Haskey, PhD

CONTACT

[email protected]

250-807-9597

Sponsors and collaborators

Lead sponsor

University of British Columbia

Other

Collaborators

  • University of Calgary

Registry information

Official study title

Predicting Microbiome-Associated Personalized Responses to the Mediterranean Diet

Acronym: MAP-Med

Important dates

Study start
2025
Primary completion
2025
Study completion
2026
First posted
Jan 9, 2025
Registry last updated
Jan 9, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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