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Effects of California Walnuts on Vascular Function in Postmenopausal Women

This study has been completed.
California Walnut Commission
Information provided by:
University of California, Davis Identifier:
First received: February 18, 2010
Last updated: October 28, 2010
Last verified: October 2010

To determine the potential acute cardiovascular benefits of California Walnuts in postmenopausal women of ages 55-70.

Primary outcome measures:

  • Vascular function
  • Platelet reactivity

We hypothesize that the consumption of California walnuts will improve vascular function and platelet reactivity.

Condition Intervention Phase
Cardiovascular Diseases
Other: Walnuts
Phase 1

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Open Label
Primary Purpose: Basic Science
Official Title: Effects of California Walnuts on Vascular Function in Postmenopausal Women

Further study details as provided by University of California, Davis:

Primary Outcome Measures:
  • Peripheral Arterial Tonometry (PAT) [ Time Frame: 2 and 4 hours ]

Enrollment: 5
Study Start Date: June 2010
Study Completion Date: September 2010
Primary Completion Date: August 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: 5 g of walnuts Other: Walnuts
Consumption of 5 g of walnuts.
Experimental: 20 g of walnuts Other: Walnuts
Consumption of 20 g of walnuts.
Experimental: 30 g of walnuts Other: Walnuts
Consumption of 30 g of walnuts.
Experimental: 40 g of walnuts Other: Walnuts
Consumption of 40 g of walnuts.

Detailed Description:

Epidemiological studies have shown that consumption of high amounts of plant foods, such as nuts, fruits and vegetables, appears to be protective against chronic diseases including heart disease, stroke, diabetes mellitus and metabolic syndrome. In recent years, numerous studies indicate that consumption of walnuts mainly containing α-linolenic acid (ALA), L-arginine and polyphenols beneficially alters vascular function and reduces inflammatory biomarkers. Recent studies have reported that consumption of walnuts is associated with beneficial effects in prevention of chronic diseases by favorably altering human serum profiles (i.e. decrease in LDL cholesterol and triglycerides and increase in HDL cholesterol and apolipoprotein A1) which are closely involved in the development of cardiovascular disease (CVD). In addition, recent reports by Dr. Ros and his colleagues indicate that addition of walnuts to a high-fat meal can improve endothelial function. This favorable influence on vasoactivity has been attributed to the antioxidant and anti-inflammatory properties of components of walnuts.

Due to their age and menopausal status, postmenopausal women in particular, are at a greater risk population for developing CVD. Males tend to show greater rates of CVD than pre-menopausal women, while women following menopause show an increase in the rates of CVD. This increase is associated with endothelial dysfunction and decreased vasodilation which are apparently expressed after menopause and become worse with age. In this study, we will define the effects of consuming California walnuts on vascular health.

We hypothesize that consumption of California walnuts, which are particularly rich in ALA, L-arginine and polyphenols, will improve endothelial function and platelet reactivity in an at-risk population of postmenopausal women 50-70 years of age.


Ages Eligible for Study:   50 Years to 70 Years   (Adult, Senior)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • 50 to 70 years of age
  • Lack of menses in the last year and FSH 23-116.3 mlU/mL
  • Subject is willing and able to comply with the study protocols.
  • Subject is willing to consume up to 40 g of California walnuts.
  • BMI 18.5-34.9 kg/m2
  • Weight ≥ 110 pounds

Exclusion Criteria:

  • BMI ≥ 35 kg/m2
  • Weight <110 pounds
  • Diabetes
  • Taking anticoagulation medication including NSAIDs
  • Blood pressure ≥ 160/90 mm Hg
  • PFA-100 readings 10 % outside of normal reference range (normal reference range for ADP-Collagen: 71-118 sec; Epinephrine-Collagen: 94-193 sec).
  • Renal or liver disease
  • Heart disease, which includes cardiovascular events and Stroke
  • Cushing's syndrome
  • Chronic/routine high intensity exercise
  • Inability to properly place or wear the PAT probes or abnormal measurements on pre-screening PAT
  • Abnormal Liver, CBC or CMP (laboratory values outside the reference range) if determined to be clinically significant.
  • History of cancer
  • History of psychiatric disorders i.e. schizophrenia or bi-polar or depression treated with antidepressants within the last 1 year.
  • Use of MAOI inhibitor within the last 1 year (e.g. phenelzine (Nardil), tranylcypromine (Parnate), etc)
  • Malabsorption
  • Anxiety medications
  • Routine use of prescription drugs or over-the counter medications, which may potentially modulate the outcome of this study; including antibiotics, aspirin and aspirin-containing formulations, COX-2 inhibitors, antihistamines, corticosteroids, ACE-inhibitors, and beta-blockers.
  • Asthma (can be worsened by mild to moderate food allergies).
  • Indications of substance or alcohol abuse within the last 3 years
  • Use of multivitamin/mineral supplements
  • Use of herbal or plant-based supplements; omega-3 fatty acids, and fish oils in the past 3-6 months.
  • Nut allergies
  • Soy-derived supplements
  • Soy/soy products consumption > 2 servings/week
  • Hormone replacement therapy
  • Alcohol consumption > 1 drink/day (i.e. 1 bottle of beer, ½ glass of wine, and 1 shot of hard liquor)
  • Fruit consumption ≥ 3 cups (6 servings)/day
  • Vegetable consumption ≥ 4 cups (8 servings)/day
  • Grain consumption ≥ 8 oz/day
  • Meat and Beans ≥ 7 oz/day
  • Fatty Fish ≥ 3 times/week
  • Milk ≥ 5 cups/day
  • Oil ≥ 8 tsp/day
  • Coffee/tea ≥ 3 cups/day
  • Dark chocolate ≥ 3 oz/day
  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: NCT01072864

United States, California
Ragle Human Nutrition Research Center
Davis, California, United States, 95616
Sponsors and Collaborators
University of California, Davis
California Walnut Commission
Principal Investigator: Robert M. Hackman, PhD University of California, Davis
  More Information

Responsible Party: Robert M. Hackman, University of California, Davis Identifier: NCT01072864     History of Changes
Other Study ID Numbers: 200917508-1
Study First Received: February 18, 2010
Last Updated: October 28, 2010

Keywords provided by University of California, Davis:

Additional relevant MeSH terms:
Cardiovascular Diseases processed this record on April 25, 2017