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Postprandial Effects of Walnut Components Versus Whole Walnuts on Cardiovascular Disease (CVD) Risk Reduction

This study has been completed.
California Walnut Commission
Information provided by:
Penn State University Identifier:
First received: June 18, 2009
Last updated: July 10, 2009
Last verified: July 2009
The purpose of this study is to evaluate the acute, postprandial effects and mechanism of action of various walnut components (separated nut skins, de-fatted nut meat, nut oil) versus whole walnuts on oxidative stress, inflammation and measures of platelet and endothelial function in healthy adults with moderately elevated cholesterol levels.

Condition Intervention
Cardiovascular Disease Dietary Supplement: Walnut "meat" Dietary Supplement: Walnut Oil Dietary Supplement: Walnut Skins

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Prevention
Official Title: Postprandial Effects of Walnut Components vs Whole Walnuts on Oxidative Stress, Inflammation, Platelet Function, and Endothelial Function in Volunteers With Moderate Hypercholesterolemia

Resource links provided by NLM:

Further study details as provided by Penn State University:

Primary Outcome Measures:
  • Measures of antioxidant capacity [ Time Frame: Postprandial - Baseline, 1hr, 2hr, 4hr and 6hr ]
  • Markers of Oxidative Stress [ Time Frame: Postprandial - Baseline, 1 hr, 2hr, 4hr, 6hr ]
  • Measures of Inflammation [ Time Frame: Postprandial - Baseline, 1 hr, 2hr, 4hr, 6hr ]

Secondary Outcome Measures:
  • Measures of Platelet Function [ Time Frame: Postprandial - Baseline, 1 hr, 2hr, 4hr, 6hr ]
  • Endothelial Function [ Time Frame: Baseline + 4 hours PP ]

Enrollment: 20
Study Start Date: August 2007
Study Completion Date: May 2009
Primary Completion Date: February 2009 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Experimental: Whole walnut
85g whole walnuts, ground, incorporated into inert food carrier
Dietary Supplement: Walnut "meat"
Separated, ground walnut de-fatted nut meat incorporated into inert food carrier
Dietary Supplement: Walnut Oil
Walnut oil extracted from nut meat and incorporated into inert food carrier
Dietary Supplement: Walnut Skins
Separated, ground walnut skins incorporated into inert food carrier

Detailed Description:
Walnuts contain high contents of polyunsaturated fatty acids (PUFA), particularly linoleic acid and linolenic acid. The high PUFA content has been suggested to reduce CVD risk through decreasing total and LDL-cholesterol concentrations, and increasing HDL-C concentrations. In addition, walnuts are rich in substances such as ellagic acid (a polyphenol), antioxidants, vitamin E, fiber, essential fatty acids, flavanoids, and phenolic acids. Polyphenolic compounds are believed to have multiple biological effects influencing oxidative stress, platelet function, inflammation, and cancer initiation and propagation. There is interest in identifying foods with these and other favorable compounds to test their efficacy in real world settings to further understand their role in the human diet. Despite positive benefits found in consumption of the walnuts, it is not known which specific component of the walnut (i.e., whole walnut, walnut skin, defatted walnut, or walnut oil) is most beneficial to health. The investigators hypothesize that maximum improvements in oxidative stress, inflammatory markers, platelet and endothelial function will be observed following consumption of the whole nut versus isolated walnut components, thereby leading to a recommendation to consume walnuts. In addition, results from the research proposed will provide new information about the antioxidant, inflammatory, platelet activity and endothelial effects of the different walnut components and the synergistic effects these components have in the postprandial state.

Ages Eligible for Study:   21 Years to 60 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Age 21 - 60 years
  • Body mass index 25-39 kg/m2
  • LDL cholesterol >110 mg/dL
  • <95 percentile for age and gender for both (based on NHANES data)
  • TG < 350 mg/dL

Exclusion Criteria:

  • High alcohol consumption > 21 units/week (female subjects) or > 28 units/week (male subjects)
  • Intake of vitamin and mineral supplements within the past 3 weeks or unwillingness to discontinue for 3 weeks prior to screening and for entire study.
  • Use of prescription cholesterol-lowering or blood pressure-lowering medications during the study
  • Intake of other putative cholesterol-lowering supplements (excl. psyllium, fish oil capsules, soy lecithin, phytoestrogens)
  • Intake of anti-inflammatory medications (containing aspirin or NSAIDS) on a regular basis or if an acute intake, within 48 hours of a test day
  • Diabetes, liver, kidney, thyroid (unless controlled and stable on replacement medication) or other endocrine disorders from self-reported medical history
  • Treatment with drugs acting on the gut, such as ezetimibe, bile acid-binding resins, orlistat
  • Dietary restrictions such as a medically prescribed diet, or a slimming diet prior to or during the trial
  • Weight loss or gain of 10% body weight or more during a period of 6 months before pre-study examination.
  • Blood/plasma donation for reason(s) other than the present study prior to the study (1 month for a male subject or 2 months for a female subject), or during the study
  • Lactation 6 weeks before the start of and during study, pregnant or wishing to become pregnant 3 months before or during the study
  Contacts and Locations
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Please refer to this study by its identifier: NCT00938340

Sponsors and Collaborators
Penn State University
California Walnut Commission
Principal Investigator: Penny M Kris-Etherton, PhD Penn State University
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Penny Kris-Etherton, PhD, Penn State University Identifier: NCT00938340     History of Changes
Other Study ID Numbers: PKE 102
Study First Received: June 18, 2009
Last Updated: July 10, 2009

Keywords provided by Penn State University:
Cardiovascular Disease

Additional relevant MeSH terms:
Cardiovascular Diseases processed this record on August 18, 2017