Effects of Walnut Consumption on Endothelial Function in Type 2 Diabetes (WALNUT)

March 25, 2020 updated by: Griffin Hospital

Effects of Walnut Consumption on Endothelial Function in Type 2 Diabetes: A Randomized, Controlled, Cross-over Trial

The purpose of this study is to examine the effects of sustained walnut consumption on endothelial function and lipid markers in patients with Type 2 diabetes mellitus.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

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.

Detailed Description

Evidence-based guidelines for the management of type 2 diabetes mellitus and related cardiovascular disease (CVD) refer to cardioprotective dietary fatty acid proportions. Several studies demonstrate the hypocholesteremic effects of walnuts in energy restricted diets. To our knowledge, the health benefits accrued as a result of addition of walnuts to an ad libitum diet in type 2 diabetic subjects have not been studied. Addition of walnuts to an ad libitum diet represents a practical way to achieve the recommended fatty acid proportions. The proposed study will examine whether a total dietary pattern inclusive of walnuts, will result in amelioration of cardiac risk as measured by improvement in endothelial function and glycemic control in type 2 diabetics. Results of the study will have important implications for clinicians and dietitians in dietary management of type 2 diabetes. Demonstrating that walnuts can be regarded as beneficial components of dietary management of type 2 diabetes is of relevance to the walnut industry as well. The study employs a pragmatic approach to approximate dietary practices in a real world setting thus enhancing the external validity of the study. If positive, the study results can inform future marketing efforts of the California Walnut Commission. Demonstrating that addition of walnuts to an ad libitum diet can potentially lead to improvement in endothelial function, improve lipid profiles, glycemic control and reduce the risk of CVD complications in diabetic patients has important applications for dietary management of diabetes.

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.
24

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 Locations

  • United States
    • Connecticut
      • Derby, Connecticut, United States, 06418
        • Griffin Hospital

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

35 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  1. men and women ages 35-75
  2. non-smoker
  3. able to have blood pressure taken bilaterally
  4. diagnosed with type 2 diabetes by physician for at least one year
  5. stable glucose levels and medication dose for the past 3 months
  6. not on insulin therapy

Exclusion Criteria:

  1. failure to meet inclusion criteria
  2. anticipated inability to complete or comply with study protocol for any reason (e.g., inability to communicate in English, dementia) or any unstable medical condition that would limit the ability of a subject to participate fully in the trial (e.g., wasting illness, AIDS, tuberculosis, psychotic disorder)
  3. diagnosed eating disorder
  4. use of lipid-lowering or antihypertensive medications (statins, red rice yeast extract, garlic) unless stable on medication for at least 3 months and willing to refrain from taking medication for 12 hours prior to endothelial function (EF) scanning, vasoactive medication (i.e., glucocorticoids, antineoplastic agents, psychoactive agents, or bronchodilators) or nutriceuticals
  5. regular use of multivitamins and/or complementary or alternative supplement therapy and unwillingness to discontinue supplementation for at least 8 weeks prior to study initiation and for study duration
  6. any rheumatologic disease requiring regular use of nonsteroidal antiinflammatory drug (NSAIDs) or alternative medications
  7. regular use of fiber supplements
  8. preexisting cardiovascular disease, including symptomatic coronary artery disease (CAD), myocardial infarction, angina pectoris, anginal equivalent, peripheral vascular disease (claudication, amputation, or revascularization) congestive heart failure, carotid stenosis, aortic stenosis or stroke; diabetes, sleep apnea, severe uncontrolled hypertension (systolic blood pressure > 180 mmHg or diastolic blood pressure > 105 mmHg)
  9. coagulopathy, known bleeding diathesis or history of clinically significant hemorrhage; current use of warfarin
  10. clinically significant anemia (Hct < 36% in men, < 33% in women)
  11. intestinal or stomach disease
  12. inability to use right or left arm for endothelial function testing for any reason such as breast surgery, trauma, radiation to right axilla, lymphedema, right arm shunt, severe vascular disease in right arm
  13. subjects on a disease specific diet
  14. subjects on a weight control diet
  15. subjects on a vegan diet
  16. allergy to any kind of nut, including walnuts and peanuts

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: None (Open Label)

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: Walnut supplementation
Eight weeks with walnut supplementation to an ad lib diet
Dietary supplement: Walnut supplementation
Eight weeks of walnut supplementation
Active Comparator: Ad lib diet
Eight weeks ad lib diet without walnut supplementation
Dietary supplement: Ad lib diet
Eight weeks without walnut supplementation

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
Time Frame
Brachial artery flow mediated dilation (FMD)
Time Frame: 8 weeks
8 weeks

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
Time Frame
Change in weight, waist circumference, blood pressure, fasting lipids, fasting insulin, HBA1c and glucose levels
Time Frame: 8 weeks
8 weeks

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.
Griffin Hospital

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
California Walnut Commission

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: DAVID L KATZ, MD, Yale-Griffin Prevention Research Center

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

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.
October 1, 2007

Primary Completion (Actual)

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.
July 1, 2008

Study Completion (Actual)

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.
September 1, 2008

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 12, 2009

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.
May 12, 2009

First Posted (Estimate)

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.
May 13, 2009

Study Record Updates

Last Update Posted (Actual)

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.
March 26, 2020

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.
March 25, 2020

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.
March 1, 2020

More Information

Terms related to this study

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.
  • 2007-10

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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