Walnuts and Glucose Variability

March 17, 2014 updated by: Michelle Wien, Loma Linda University

The Effect of Walnuts on Glucose Variability in Adults With Type-2 Diabetes Mellitus: a Dose-response Metabolic Feeding Study

Persons with type 2 diabetes mellitus (T2DM) have swings in their blood sugar levels that may lead to a higher risk of developing heart disease. An important part of diabetes management involves eating a diet to prevent large swings in blood sugar levels. Walnuts contain fat, protein and fiber that may reduce the swings in blood sugar. The purpose of this study is to compare the effects of a walnut-free American Diabetes Association (ADA) diet versus 2 levels of walnut-enriched ADA diets on blood sugar swings. Eighteen male and female adults with T2DM will participate in the study. Subjects will be randomized to consume an ADA diet with or without walnuts for 3 consecutive days every other week. Subjects must test their blood sugar twice daily and wear a continuous glucose monitor during the three 72-hour study periods. Subjects will be between 40 and 70 years of age and will be recruited from the surrounding community using flyers and public service announcements. Consent will take place in the Department of Nutrition at Loma Linda University by the study investigators. In total, subject participation will last 5 weeks and all meals will be provided during the 3 study periods.

Study Overview

Status

Status

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

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.
18

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
    • California
      • Loma Linda, California, United States, 92350
        • Loma Linda University, Nichol Hall

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

40 years to 70 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • adults between age 40 and 70 years with type 2 diabetes
  • duration of type 2 diabetes more than 6 months but less than 10 years
  • HbA1c 6.0-8.0%
  • BMI 25-40 kg/m2
  • diet controlled or stable dose of metformin for at least 3 months
  • willing to test blood glucose with personal meter twice a day during study test days

Exclusion Criteria:

  • using oral hypoglycemic agents or insulin
  • history of ischemic heart disease or congestive heart failure
  • history of severe diabetic complication (neuropathy, renal failure, stroke)
  • taking medication affecting glucose levels (i.e. corticosteroids)
  • active infectious disease
  • active malignancy
  • pregnant or breast feeding woman
  • smoker
  • history of daily caffeine or alcohol intake
  • known allergy to nuts
  • lactose or gluten intolerance

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.
Active Comparator: Full dose
full dose of walnuts (20% energy needs)
Dietary supplement: Full dose
20% of daily energy needs supplied by walnuts
Active Comparator: Half-dose
Half dose of walnuts (10% of energy needs)
Dietary supplement: Half dose
10% of daily energy needs supplied by walnuts
Other: Control
Walnut free meals
Dietary supplement: Control
Walnut free meals

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
Within-day glucose variability
Time Frame: 3 days
The primary objective is to evaluate the effect of two isocaloric walnut-enriched meal plans versus a walnut-free ADA meal plan on within-day glucose variability in adults with diabetes by assessing: a) the overall standard deviation (SD) around the sensor glucose calculated for each day and then averaged over the 3-day study periods; b) the mean amplitude of glycemic excursions (MAGE) over the 3-day study periods.
3 days

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
Glucose variability dose response
Time Frame: 3 days
A secondary objective will be to test for a dose-response effect, i.e. the more walnuts (full-dose versus half-dose) the lower the glucose variability.
3 days
Dose response to between-day glycemic variability
Time Frame: 3 days
The effect of the three isocaloric ADA meal plans (full-dose, half-dose, walnut free) on the mean of the daily differences(MODD) will be recorded as a measure of between-day glycemic variability
3 days
Glucose levels by meal
Time Frame: 3 days
Glucose levels will be measured before and after breakfast, lunch and dinner for each of the three isocaloric ADA meal plans (full-dose, half-dose, walnut free)
3 days
Mean glucose of sensor range
Time Frame: 3 days
The mean of the glucose for the range captured on each sensor (sensor maximal glucose level minus minimal glucose level will be recorded
3 days
Duration of hypoglycemia
Time Frame: 3 days
The duration of hypoglycemia will be measured as hours per day for each of the three isocaloric ADA meal plans (full-dose, half-dose, walnut free)
3 days
Duration of hyperglycemia
Time Frame: 3 days
The duration of hyperglycemia will be measured as hours per day for each of the three isocaloric ADA meal plans (full-dose, half-dose, walnut free)
3 days
Net glycemia at 2 hours
Time Frame: 3 days
The continuous overall net glycemic action will be measured at 2 hour intervals
3 days
Net glycemia at 4 hours
Time Frame: 3 days
The continuous overall net glycemic action will be measured at 4 hour intervals
3 days

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.
Loma Linda University

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: Michelle Wien, DrPH, RD, Assistant Professor

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.
June 1, 2013

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.
September 1, 2013

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, 2013

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).
February 1, 2013

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.
February 6, 2013

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.
February 8, 2013

Study Record Updates

Last Update Posted (Estimate)

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 18, 2014

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 17, 2014

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, 2014

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.
  • walnuts and glucose

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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