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NCT Number: NCT07107269

Diet and Microbiome Interactions: Application in Posttraumatic Stress Disorder in Adults Consuming Vegetable Drinks

The gut microbiome has been shown to impact various facets of human health, including mental health. Studies have shown that populations with more agrarian lifestyles tend to have fewer chronic diseases and mental health issues than industrialized populations. A possible factor in these differences is the loss of co-evolved gut microbial taxa that has occurred with Westernization. This hypothesis, termed "Old Friends Hypothesis" suggests that the loss of certain gut microbes leads to immune dysregulation and increased chronic inflammation that contributes to development of cancers, cardiometabolic diseases and even neuroinflammation that can lead to negative behavioral and mental health outcomes. Other studies have shown that increasing the intake of plant foods may help increase diversity of the microbes in the gut and that this increased diversity could lead to better health outcomes in humans.

The investigators propose to evaluate daily consumption of a drink consisting of a high diversity of plants (30 plant species) for four weeks on the diversity of the gut microbiome, biological signatures of inflammation, quality of life, sleep quality, and PTSD symptoms among persons with a diagnosis of PTSD.

The investigators hypothesize that four weeks of daily consumption of this high plant diversity beverage (30 plant species) will increase gut microbiome ɑ-diversity, reduce markers of systemic inflammation, and improve PTSD symptom severity relative to daily consumption of a beverage containing only three plant species.

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Key information

Conditions

PTSD - Post Traumatic Stress Disorder Combat Disorders Mental Disorders Stress Disorders, Post-Traumatic Stress Disorders, Traumatic Trauma and Stressor Related Disorders

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Food and Nutrition Clinical Research Lab - Colorado State University

Fort Collins, Colorado, 80523, United States

About this study

The intervention will be a double-blind parallel arm study that consists of a four-week treatment period where participants will be randomized to either the experimental or control arm of the study.

During this four-week treatment period the participants will consume either a 4 oz beverage consisting of 30 different blended vegetables (high diversity treatment) or a similar control beverage consisting of 4 oz of blended Power Greens mix, containing only 3 different plant species (low diversity F&V treatment).

The participants will be asked to provide 2-day diet records every two weeks throughout the study. Participants will also complete daily bowel movement records using the Bristol Stool Scale (BSS) and collect 3 fecal samples (baseline, mid-point and final) that will be returned to the clinic at scheduled visits. Blood samples and gut, sleep, and mental health questionnaire data will be collected at the beginning and end of the study.

Primary objectives are as follows:

Objective 1: To determine whether consuming a higher number of plant types, thereby increasing exposure to diverse plant-associated microbes, increases gut microbial diversity. Specifically, investigators will use fecal samples from individuals before and after 4-week consumption of a 4 oz beverage made with high (30 different plants) and low botanical diversity (3 different plants) to assess taxonomic richness (CHAO) and diversity (Shannon) using 16s rRNA and metagenomic sequencing approaches.

Objective 2: To determine how differences in plant diversity consumption influence inflammation and immune signatures, specifically plasma hsCRP levels and number/type of circulating T-regulatory cells. hsCRP will be assayed using ELISA and T-cells and other immune cells will be profiled from collected peripheral blood mononucleocytes (PBMCs) via flow cytometry.

Objective 3: To determine whether gut microbial diversity and inflammatory profiles correlate with PTSD symptom severity. PTSD symptoms will be evaluated at each visit using the PCL-5 assessment and changes with treatment as well as correlates with other primary outcome measures will be determined.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Healthy adults (18-60 years old)
  • Diagnosis of PTSD
  • BMI<35
  • Willing to follow all study criteria

Exclusion criteria

  • Antibiotic use within 3 months
  • BMI of 35 or higher
  • Vegan or vegetarian
  • Allergies to any intervention beverages
  • Unstable medication regimen
  • Any gastrointestinal diseases, cancer, CVD, diabetes, autoimmune disease, pregnant or breastfeeding
  • Any medication changes within last two months

Treatment and study plan

Low diversity plant beverage (Functional Food Intervention)

Other

Blended drink made from 3 organic vegetables (Power Greens mix)

High diversity plant beverage (Functional Food Intervention)

Other

This is a 4oz shot made from 30 different organic vegetables and packaged in mylar pouches.

Primary outcomes

  1. Changes in self-assessed severity of post-traumatic stress disorder (PTSD) symptoms

    Time frame: From enrollment to the end of the 4-week intervention period.

    PTSD Checklist for DSM-5 or the PCL-5 questionnaire.

    The PCL-5 is a 20-item self-report measure that assesses the 20 DSM-5 symptoms of PTSD. The PCL-5 has a variety of purposes, including:

    Monitoring symptom change during and after treatment Screening individuals for PTSD Making a provisional PTSD diagnosis

    A higher score on the PCL-5 indicates a greater level of distress and impairment associated with PTSD symptoms. The total score ranges from 0 to 80, with higher scores reflecting a more severe symptomatology. A total score of 32 or above suggests the presence of clinically significant PTSD symptoms, which may require further assessment and treatment.

  2. Gut Microbiota Richness

    Time frame: From enrollment to the end of the 4-week intervention period.

    Microbiota richness will be determined by the number of amplicon sequence variants (actual or estimated) in a fecal sample.

  3. Gut microbiota diversity

    Time frame: From enrollment to the end of the 4-week intervention period.

    The Shannon-Wiener index will be applied to 16s rRNA amplicon sequence variants to determine microbial community diversity within a fecal sample.

  4. C-reactive protein in plasma

    Time frame: From enrollment to the end of the 4-week intervention period.

    CRP, or C-reactive protein, is a substance produced by the liver in response to inflammation in the body. It is commonly measured in blood using a high sensitivity ELISA test to assess general inflammation levels, helping to identify underlying health issues such as infections, tissue injury, or chronic inflammatory diseases. Elevated levels of CRP are associated with PTSD.

Secondary outcomes

  1. Seated Blood Pressure

    Time frame: From enrollment to the end of the 4-week intervention period.

    Average of 3 seated brachial blood pressure readings taken in the clinic at each visit.

  2. Changes in T-cell populations

    Time frame: From enrollment to the end of the 4-week intervention period.

    Using flow cytometry to look at the number and types of T-cells in peripheral blood mononuclear cells can be used to look at changes in immune response and inflammation.

Sponsors and collaborators

Lead sponsor

Colorado State University

Other

Collaborators

  • University of Colorado, Denver
  • University of Utah

Registry information

Official study title

Diet and Microbiome Interactions: Application in Posttraumatic Stress Disorder

Acronym: DMAPS

Important dates

Study start
2025
Primary completion
2026
Study completion
2026
First posted
Aug 6, 2025
Registry last updated
Jul 14, 2026

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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