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

Study Overview
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Brief Summary
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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.

Detailed Description
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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.

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

Conditions
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Aging

Intervention / Treatment
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* Dietary Supplement: PECAN


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| No Intervention: Control<br>Participants in this group avoid all nuts for 4-weeks | |
| Experimental: PECAN<br>Participants in this group consume 68 g of pecans/d with no other changes to their habitual diet and avoid all other nuts. | Dietary Supplement: PECAN<br>* Raw pecan halves without other changes to their habitual diet.<br>|

What is the study measuring?
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Primary Outcome Measures

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

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in fasting blood lipids from baseline to 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) | Baseline and 4 weeks | 
| Change in baseline weight at 4 weeks | weight (kg) | Baseline and 4 weeks | 
| Change in baseline waist and hip circumference | waist and hip circumference (cm) | Baseline and 4 weeks | 
| Change in blood pressure from baseline to 4 weeks | Systolic and Diastolic Blood Pressure (mm Hg) | Baseline and 4 weeks | 
| Change in baseline total body fat percentage at 4 weeks | total body fat percentage (%) | Baseline and 4 weeks | 
| Change in fasting and postprandial insulin from baseline to 4 weeks | Insulin (uU/mL) | Baseline and 4 weeks | 
| Change in fasting and postprandial antioxidants from baseline to 4 weeks | Total antioxidant capacity (uM trolox equivalents) measured via Oxygen Radical Absorbance Capacity (ORAC) | Baseline and 4 weeks | 
| Change in fasting and postprandial lipid peroxidation from baseline to 4 weeks | Malondialdehyde (MDA) (uM) measured via Thiobarbituric acid reactive substances (TBARS) assay. | Baseline and 4 weeks | 
| Change in fasting inflammation from baseline to 4 weeks | Interleukin-6 (pg/mL), C-reactive Protein (pg/mL), Tumor Necrosis Factor-α (pg/mL), Plasminogen Activator-1 (pg/mL) | Baseline and 4 weeks | 
| Change in fasting and postprandial glucose and triglycerides from baseline to 4 weeks | Glucose (mg/dL) and triglycerides (mg/dL) | Baseline and 4 weeks | 
| Change in fasting and postprandial peptide YY, cholecystokinin (CCK), and ghrelin from baseline to 4 weeks | Peptide YY (pg/mL), CCK (pg/mL), ghrelin (pg/mL) | Baseline and 4 weeks | 
| Change in fasting and postprandial non-esterified free fatty acids (NEFA) from baseline to 4 weeks | NEFA (mEq/L) | Baseline and 4 weeks | 
| Change in fasting and postprandial hunger and satiety from baseline to 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) | Baseline and 4 weeks |