Walnut Consumption and Gut Microbiota

June 15, 2023 updated by: Hannah Holscher, University of Illinois at Urbana-Champaign

The Microbial and Metabolic Impact of Walnut Consumption in Adults With Obesity

Obesity is a growing health issue that effects the majority of adults in the United States. Prevalence of other metabolic diseases are increased in obese adults, including systemic inflammation. There is emerging evidence that the gut microbiota have a mediating role in controlling inflammation by producing butyrate when ingested fiber is fermented. Since these microbes are modifiable by diet, the investigators plan to introduce walnuts to the diets of participants with obesity because they are rich in fiber and unsaturated fatty acids. The purpose of this study is to understand the impacts of walnut consumption on the gut microbiota and the effect they have on bile acid profiles and systemic inflammation. The investigators intention is to identify how these walnut-derived molecules influence Faecalibacterium spp., a butyrate producing microbe. Increased levels of butyrate have shown to decrease secondary bile acids and decrease inflammation.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
30

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

  • United States
    • Illinois
      • Urbana, Illinois, United States, 61801
        • Hannah Holscher

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

25 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

Participants will include adults ages 25-75 years BMI of > 30 kg/m2 Ability to drop-off fecal sample within 15 minutes of defecation

Exclusion Criteria:

  • Walnut allergy or intolerance
  • Food allergies or intolerances
  • Prior diagnosis of metabolic or gastrointestinal disease (cardiovascular disease and type 1 or type 2 diabetes, chronic constipation, diarrhea, Crohn's disease, celiac disease, ulcerative colitis, irritable bowel syndrome, diverticulosis, stomach or duodenal ulcers, hepatitis, HIV, cancer, etc.)
  • Women that are pregnant, had a baby within the last 12 months, or lactating
  • Individuals that smoke, use tobacco, abuse drugs, or consume > 2 alcoholic beverages per day.
  • > 5% weight change in the past month or > 10% change in the past year
  • Oral antibiotics during the previous 6 weeks
  • Fasting blood glucose >126 mg/dL, blood pressure >160/100 mm Hg, elevation in serum transaminases (i.e. >3 times the upper limit of normal) or with evidence of liver disease, including primary biliary cirrhosis or gallbladder disease, constipation, are currently taking lipid-lowering medications, oral hypoglycemic agents, or insulin, or certain medications (laxatives, bile acid sequestrants, and opiates)
  • History of malabsorptive or restrictive bariatric surgeries (e.g., gastric bypass, sleeve gastrectomy, adjustable gastric band) or gall bladder removal surgery.
  • Are unable to consume the experimental meals/snacks.
  • Participants who have donated blood within the last 8 weeks
  • Recent diagnosis of anemia
  • Concurrent enrollment in another dietary, exercise, or medication study

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Intervention treatment
Intervention treatment will contain walnuts and be consumed everyday for 3 weeks.
Other: Walnuts
The intervention treatment will contain walnuts.
Experimental: Intervention treatment oil
Intervention treatment will contain walnut oil in foods and be consumed everyday for 3 weeks.
Other: Walnut Oil
The intervention treatment will contain walnut oil.
Placebo Comparator: Control treatment
Intervention treatment will contain corn oil in foods and be consumed everyday for 3 weeks.
Other: Control
The control treatment will contain corn oil.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Fecal Microbial Species
Time Frame: Fecal samples will be collected at the end of each 3 week condition.
Abundances of fecal Faecalibacterium spp. and Roseburia spp measured using metagenomic sequencing in walnut and walnut oil vs. control.
Fecal samples will be collected at the end of each 3 week condition.
Concentration of fecal bile acids
Time Frame: Fecal samples will be collected at the end of each 3 week condition.
Fecal bile acid concentrations measured using HPLC in walnut and walnut oil vs. control
Fecal samples will be collected at the end of each 3 week condition.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Fecal Microbial Metabolites
Time Frame: Fecal samples will be collected once at the end of each 3 week condition.
Concentrations of fecal microbial metabolite (phenol/indoles, short chain fatty acids, and ammonia) concentrations measured using GC-MS in walnut and walnut oil in comparison to a control (corn oil)
Fecal samples will be collected once at the end of each 3 week condition.

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Fecal Microbiome
Time Frame: Fecal samples will be collected at the end of each 3 week condition.
Relative abundance of microbial genes and genera measured using metagenomic sequencing of extracted fecal DNA to compare abundances between walnut, walnut oil, and corn oil.
Fecal samples will be collected at the end of each 3 week condition.
Inflammatory markers
Time Frame: Blood samples will be collected at the end of each 3 week condition.
LPS-binding protein and inflammatory markers (CRP and TNFa) concentrations in walnut and walnut oil vs. control (corn oil)
Blood samples will be collected at the end of each 3 week condition.
Serum bile acid profiles
Time Frame: Blood samples will be collected during a mixed-meal tolerance test that occurs at the end of each 3 week condition.
Serum bile acid concentrations will be measured using LC-ESI-MS/MS to compare concentrations between walnut and walnut oil and control (corn oil)
Blood samples will be collected during a mixed-meal tolerance test that occurs at the end of each 3 week condition.
Mixed-meal tolerance test
Time Frame: At the end of each 3 week condition.
Blood glucose and insulin concentrations and area under the curve will be measured in blood during a mixed meal tolerance test that includes a standard glucose beverage and the respective walnut, walnut oil, or corn oil treatment.
At the end of each 3 week condition.
Intestinal permeability
Time Frame: 24-hour urine collections will occur at the end of each 3 week condition
Intestinal permeability will be measured using a orally ingested sugar substitutes. 24-hour urinary appearance of the sugars will be quantified using GC-MS.
24-hour urine collections will occur at the end of each 3 week condition

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of Illinois at Urbana-Champaign

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 1, 2022

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
August 1, 2023

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
July 1, 2024

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 6, 2021

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 28, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 1, 2022

Study Record Updates

Last Update Posted (Estimated)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 19, 2023

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 15, 2023

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
June 1, 2023

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 20164

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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