Effects of Walnut Consumption on Endothelial Function in Type 2 Diabetes (WALNUT)
Primary Purpose
DIABETES MELLITUS TYPE 2
Status
Completed
Phase
Not Applicable
Locations
United States
Study Type
Interventional
Intervention
Walnut supplementation
Ad lib diet
Sponsored by
About this trial
This is an interventional treatment trial for DIABETES MELLITUS TYPE 2
Eligibility Criteria
Inclusion Criteria:
- men and women ages 35-75
- non-smoker
- able to have blood pressure taken bilaterally
- diagnosed with type 2 diabetes by physician for at least one year
- stable glucose levels and medication dose for the past 3 months
- not on insulin therapy
Exclusion Criteria:
- failure to meet inclusion criteria
- 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)
- diagnosed eating disorder
- 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
- 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
- any rheumatologic disease requiring regular use of nonsteroidal antiinflammatory drug (NSAIDs) or alternative medications
- regular use of fiber supplements
- 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)
- coagulopathy, known bleeding diathesis or history of clinically significant hemorrhage; current use of warfarin
- clinically significant anemia (Hct < 36% in men, < 33% in women)
- intestinal or stomach disease
- 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
- subjects on a disease specific diet
- subjects on a weight control diet
- subjects on a vegan diet
- allergy to any kind of nut, including walnuts and peanuts
Sites / Locations
- Griffin Hospital
Arms of the Study
Arm 1
Arm 2
Arm Type
Experimental
Active Comparator
Arm Label
Walnut supplementation
Ad lib diet
Arm Description
Eight weeks with walnut supplementation to an ad lib diet
Eight weeks ad lib diet without walnut supplementation
Outcomes
Primary Outcome Measures
Brachial artery flow mediated dilation (FMD)
Secondary Outcome Measures
Change in weight, waist circumference, blood pressure, fasting lipids, fasting insulin, HBA1c and glucose levels
Full Information
NCT ID
NCT00901043
First Posted
May 12, 2009
Last Updated
March 25, 2020
Sponsor
Griffin Hospital
Collaborators
California Walnut Commission
1. Study Identification
Unique Protocol Identification Number
NCT00901043
Brief Title
Effects of Walnut Consumption on Endothelial Function in Type 2 Diabetes
Acronym
WALNUT
Official Title
Effects of Walnut Consumption on Endothelial Function in Type 2 Diabetes: A Randomized, Controlled, Cross-over Trial
Study Type
Interventional
2. Study Status
Record Verification Date
March 2020
Overall Recruitment Status
Completed
Study Start Date
October 2007 (undefined)
Primary Completion Date
July 2008 (Actual)
Study Completion Date
September 2008 (Actual)
3. Sponsor/Collaborators
Responsible Party, by Official Title
Sponsor
Name of the Sponsor
Griffin Hospital
Collaborators
California Walnut Commission
4. Oversight
Data Monitoring Committee
No
5. Study Description
Brief Summary
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.
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.
6. Conditions and Keywords
Primary Disease or Condition Being Studied in the Trial, or the Focus of the Study
DIABETES MELLITUS TYPE 2
7. Study Design
Primary Purpose
Treatment
Study Phase
Not Applicable
Interventional Study Model
Crossover Assignment
Masking
None (Open Label)
Allocation
Randomized
Enrollment
24 (Actual)
8. Arms, Groups, and Interventions
Arm Title
Walnut supplementation
Arm Type
Experimental
Arm Description
Eight weeks with walnut supplementation to an ad lib diet
Arm Title
Ad lib diet
Arm Type
Active Comparator
Arm Description
Eight weeks ad lib diet without walnut supplementation
Intervention Type
Dietary Supplement
Intervention Name(s)
Walnut supplementation
Intervention Description
Eight weeks of walnut supplementation
Intervention Type
Dietary Supplement
Intervention Name(s)
Ad lib diet
Intervention Description
Eight weeks without walnut supplementation
Primary Outcome Measure Information:
Title
Brachial artery flow mediated dilation (FMD)
Time Frame
8 weeks
Secondary Outcome Measure Information:
Title
Change in weight, waist circumference, blood pressure, fasting lipids, fasting insulin, HBA1c and glucose levels
Time Frame
8 weeks
10. Eligibility
Sex
All
Minimum Age & Unit of Time
35 Years
Maximum Age & Unit of Time
75 Years
Accepts Healthy Volunteers
No
Eligibility Criteria
Inclusion Criteria:
men and women ages 35-75
non-smoker
able to have blood pressure taken bilaterally
diagnosed with type 2 diabetes by physician for at least one year
stable glucose levels and medication dose for the past 3 months
not on insulin therapy
Exclusion Criteria:
failure to meet inclusion criteria
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)
diagnosed eating disorder
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
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
any rheumatologic disease requiring regular use of nonsteroidal antiinflammatory drug (NSAIDs) or alternative medications
regular use of fiber supplements
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)
coagulopathy, known bleeding diathesis or history of clinically significant hemorrhage; current use of warfarin
clinically significant anemia (Hct < 36% in men, < 33% in women)
intestinal or stomach disease
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
subjects on a disease specific diet
subjects on a weight control diet
subjects on a vegan diet
allergy to any kind of nut, including walnuts and peanuts
Overall Study Officials:
First Name & Middle Initial & Last Name & Degree
DAVID L KATZ, MD
Organizational Affiliation
Yale-Griffin Prevention Research Center
Official's Role
Principal Investigator
Facility Information:
Facility Name
Griffin Hospital
City
Derby
State/Province
Connecticut
ZIP/Postal Code
06418
Country
United States
12. IPD Sharing Statement
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Effects of Walnut Consumption on Endothelial Function in Type 2 Diabetes
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