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Walnuts and Glucose Variability

This study has been terminated.
(Funding withdrawn)
California Walnut Commission
Information provided by (Responsible Party):
Michelle Wien, Loma Linda University Identifier:
First received: February 1, 2013
Last updated: March 17, 2014
Last verified: March 2014
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.

Condition Intervention
Type-2 Diabetes Dietary Supplement: Full dose Dietary Supplement: Half dose Dietary Supplement: Control

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single (Outcomes Assessor)
Primary Purpose: Treatment
Official Title: The Effect of Walnuts on Glucose Variability in Adults With Type-2 Diabetes Mellitus: a Dose-response Metabolic Feeding Study

Further study details as provided by Michelle Wien, Loma Linda University:

Primary Outcome Measures:
  • 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.

Secondary Outcome Measures:
  • 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.

  • 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

  • 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)

  • 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

  • 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)

  • 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)

  • Net glycemia at 2 hours [ Time Frame: 3 days ]
    The continuous overall net glycemic action will be measured at 2 hour intervals

  • Net glycemia at 4 hours [ Time Frame: 3 days ]
    The continuous overall net glycemic action will be measured at 4 hour intervals

Enrollment: 18
Study Start Date: June 2013
Study Completion Date: September 2013
Primary Completion Date: September 2013 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
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
Walnut free meals
Dietary Supplement: Control
Walnut free meals


Ages Eligible for Study:   40 Years to 70 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

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
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01787214

United States, California
Loma Linda University, Nichol Hall
Loma Linda, California, United States, 92350
Sponsors and Collaborators
Loma Linda University
California Walnut Commission
Principal Investigator: Michelle Wien, DrPH, RD Assistant Professor
  More Information

Responsible Party: Michelle Wien, Assistant Professor, Loma Linda University Identifier: NCT01787214     History of Changes
Other Study ID Numbers: walnuts and glucose
Study First Received: February 1, 2013
Last Updated: March 17, 2014

Keywords provided by Michelle Wien, Loma Linda University:
glucose variability
type-2 diabetes

Additional relevant MeSH terms:
Diabetes Mellitus, Type 2
Diabetes Mellitus
Glucose Metabolism Disorders
Metabolic Diseases
Endocrine System Diseases processed this record on September 21, 2017