The Ability of Pecan Consumption to Improve Vascular Function and Reduce Chronic Disease Risk in Aging Adults

Overview

Background: To date, there are no published studies on the effects of pecans on vascular function following a high-fat meal.

Purpose: To examine the impact of daily pecan consumption for a 4-week period on vascular health and other markers of cardiovascular disease risk in aging adults.

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Prevention
    • Masking: None (Open Label)
  • Study Primary Completion Date: January 30, 2023

Detailed Description

This will be a randomized, controlled trial in men and postmenopausal women (50-75y). Subjects will be randomized into one of the two study groups: a control group (CON) following their usual diet, or intervention group (PECAN) following their usual diet but also consuming 68g/day of pecans as a snack.

There will be 3 visits: A Screening visit and a baseline and post-diet intervention visit (4-weeks). Anthropometrics, questionnaires, a fasting blood sample, and fasting vascular measures will be collected at each visit. Subjects will participate in a saturated fatty acid meal challenge in which additional blood, vascular measurements will be collected.

Hypothesis: Daily pecan consumption will result in improved fasting blood lipids, vascular measures, antioxidant status, and appetite compared to the control group. Additionally, also the PECAN group will result in improved postprandial blood lipids and vascular measures compared to the control group.

Interventions

  • Dietary Supplement: PECAN
    • Raw pecan halves without other changes to their habitual diet.

Arms, Groups and Cohorts

  • No Intervention: Control
    • Participants in this group avoid all nuts for 4-weeks
  • Experimental: PECAN
    • Participants in this group consume 68 g of pecans/d with no other changes to their habitual diet and avoid all other nuts.

Clinical Trial Outcome Measures

Primary Measures

  • Change in fasting and postprandial Flow-Mediated Dilation from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • Flow-Mediated Dilation %
  • Change in fasting and postprandial vessel diameter from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • baseline diameter (mm) and peak dilation (mm)
  • Change in fasting and postprandial reactive hyperemia velocity from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • Baseline velocity (cm/s) and reactive hyperemia velocity (cm/s)
  • Change in fasting and postprandial shear rate from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • baseline shear rate (sec.-1) and reactive hyperemia shear rate (sec.-1)
  • Change in fasting and postprandial Continuous-Wave Near-Infrared Spectrometry from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • O2 desaturation rate (%.sec−1), and O2 resaturation rate (%.sec−1)

Secondary Measures

  • Change in fasting blood lipids from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • Total cholesterol (mg/dL), high-density lipoprotein (HDL) cholesterol (mg/dL), triglycerides (mg/dL), low-density lipoprotein (LDL) cholesterol (mg/dL), apolipoprotein B (mg/dL)
  • Change in baseline weight at 4 weeks
    • Time Frame: Baseline and 4 weeks
    • weight (kg)
  • Change in baseline waist and hip circumference
    • Time Frame: Baseline and 4 weeks
    • waist and hip circumference (cm)
  • Change in blood pressure from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • Systolic and Diastolic Blood Pressure (mm Hg)
  • Change in baseline total body fat percentage at 4 weeks
    • Time Frame: Baseline and 4 weeks
    • total body fat percentage (%)
  • Change in fasting and postprandial insulin from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • Insulin (uU/mL)
  • Change in fasting and postprandial antioxidants from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • Total antioxidant capacity (uM trolox equivalents) measured via Oxygen Radical Absorbance Capacity (ORAC)
  • Change in fasting and postprandial lipid peroxidation from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • Malondialdehyde (MDA) (uM) measured via Thiobarbituric acid reactive substances (TBARS) assay.
  • Change in fasting inflammation from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • Interleukin-6 (pg/mL), C-reactive Protein (pg/mL), Tumor Necrosis Factor-α (pg/mL), Plasminogen Activator-1 (pg/mL)
  • Change in fasting and postprandial glucose and triglycerides from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • Glucose (mg/dL) and triglycerides (mg/dL)
  • Change in fasting and postprandial peptide YY, cholecystokinin (CCK), and ghrelin from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • Peptide YY (pg/mL), CCK (pg/mL), ghrelin (pg/mL)
  • Change in fasting and postprandial non-esterified free fatty acids (NEFA) from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • NEFA (mEq/L)
  • Change in fasting and postprandial hunger and satiety from baseline to 4 weeks
    • Time Frame: Baseline and 4 weeks
    • Hunger, fullness, prospective consumption, and desire to eat measured via a Visual Analog Scale (VAS) (mm). The range of scores on the continuous VAS is between 0mm (no hunger, fullness, prospective consumption and desire to eat) and 100mm (the greatest feeling of hunger, fullness, prospective consumption and desire to eat)

Participating in This Clinical Trial

Inclusion Criteria

  • Men and postmenopausal women (without menses for 1 yr and follicle stimulating hormone > 30 IU/mL) between the ages of 50-75y
  • Body mass indexes (BMI) between 18-34.9kg/m2

Exclusion Criteria

  • Nut consumption >2 servings/week or tree nut butter consumption >3 servings/week
  • Pre-menopausal and menopausal women, hormone replacement therapy if less than 2 years
  • Regularly exercise more than 3 h/week
  • Weight gain or loss more than 5% of their body weight in the past 3 months
  • Plans to begin a weight loss/exercise regimen during the trial
  • Gastrointestinal surgeries, conditions or disorders
  • History of medical or surgical events that could affect swallowing
  • Chronic or metabolic diseases
  • Previous MI, stroke, or cancer
  • Fasting blood glucose levels greater than 126 mg/dL
  • Blood pressure greater than 180/120 mmHg
  • Medication use affecting digestion and absorption, metabolism
  • Lipid-lowering medications
  • Medications for diabetes, depression, or ADD/ADHD
  • Regular use of medications known to affect endothelial function or blood vessel tone
  • Blood pressure medication and steroid/hormone therapies
  • Individuals on a medically prescribed or special diet
  • Individuals with food allergies to foods specifically in the study
  • Excessively use alcohol (greater than 3 drinks/d for men; greater than 2 drinks/d for women)
  • Tobacco or nicotine use
  • Individuals taking fish oil and omega-3 fatty acid supplements
  • Significant head trauma or brain surgery
  • A score >26 on the Beck's Depression Inventory II (BDI-II)
  • A score <24 on the Mini-Mental State Examination (MMSE) will be excluded.

Gender Eligibility: All

Minimum Age: 50 Years

Maximum Age: 75 Years

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • University of Georgia
  • Collaborator
    • American Pecan Council
  • Provider of Information About this Clinical Study
    • Principal Investigator: Jamie Cooper, PhD, Associate Professor, Dept. of Foods and Nutrition – University of Georgia
  • Overall Contact(s)
    • Jamie Cooper, PhD, 706-542-4903, jamie.cooper@uga.edu

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