Cardiovascular Diseases
Conditions
Brief summary
A three-period, randomized, crossover controlled feeding trial will be conducted to examine the effect of including 2 oz./day of pecans, as a snack, in a diet representative of average American intake, compared to a diet representative of average American intake devoid of nuts, and a healthy dietary pattern including 2 oz./day of pecans on markers of peripheral vascular health, lipids and lipoproteins, blood pressure, and glycemic control.
Detailed description
Participants will be randomized to each diet for 4-weeks with a minimum 2-week break between the diet periods. All caloric foods and beverages will be provided. Outcome assessments will be done at baseline and the end of each diet period.
Interventions
DRUGPecan
Unsalted raw pecans incorporated in snack and meal recipes as part of a dietary pattern
OTHERAverage American Diet devoid of nuts
Diet mimicking usual American intake
Sponsors
Penn State University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
DOUBLE (Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
25 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
* BMI ≥25 and ≤40 kg/m2 * ≥ 1 criterion for metabolic syndrome (i.e. waist circumference ≥ 94 cm men or ≥80 cm women; triglycerides ≥150 mg/dL; HDL ≤ 40 mg/dL men or ≤50 mg/dL women; systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥85 mmHg; fasting plasma glucose ≥100 mg/dL) at screening. * non-smoking
Exclusion criteria
* Current tobacco use or use within the previous 6 months * Diagnosed diabetes or fasting glucose levels \> 126 mg/dL at screening * Systolic blood pressure \>160 mm Hg or diastolic blood pressure \> 100 mm Hg at screening. * Use of anti-hypertensive, lipid lowering, glucose lowering drugs, steroids, or antibiotics in the previous month * History of a cardiovascular event (heart attack, revascularization, stroke), or heart failure, liver, kidney, autoimmune diseases or inflammatory conditions such as gastrointestinal disorders or rheumatoid arthritis * Use of supplements and botanicals known to affect study outcomes (e.g. psyllium, fish oil, soy lecithin, and phytoestrogens) and not willing to cease for the duration of the study * Pregnancy, lactation or planning to become pregnant * Consumption of \>14 alcoholic drinks/week * Intolerance/allergy/sensitivity to foods included in the study menus
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Flow mediated dilation | 4 weeks | Measured by brachial ultrasound and expressed as percent artery dilation |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| LDL-cholesterol concentration | 4 weeks | Assessed from fasting blood draw expressed in mg/dL |
| HDL-cholesterol concentrations | 4 weeks | Assessed from fasting blood draw expressed in mg/dL |
| Triglycerides | 4 weeks | Assessed from fasting blood draw expressed in mg/dL |
| LDL lipoprotein subclasses | 4 weeks | Assessed from fasting blood draw expressed in nmol/L |
| HDL lipoprotein subclasses | 4 weeks | Assessed from fasting blood draw expressed in umol/L |
| Central systolic and diastolic blood pressure | 4 weeks | Blood pressure measured assessed using a SphymoCor Ecel (Atcor Medical). |
| Carotid-femoral pulse wave velocity | 4 weeks | A measure of arterial stiffness assessed using a SphymoCor Ecel (Atcor Medical). Expressed in meters/second. |
| Augmentation Index | 4 weeks | A measure of arterial stiffness assessed using a SphymoCor Ecel (Atcor Medical). Expressed as a percentage. A higher percentage value is indicative of greater arterial stiffness. |
| Fasting plasma glucose concentration | 4 weeks | Fasting blood glucose assessed by blood draw and expressed in mg/dL |
| Serum insulin concentration | 4 weeks | Fasting serum insulin levels assessed by blood draw and expressed in micro IU/mL |
| Peripheral systolic and diastolic blood pressure | 4 weeks | Blood pressure measured assessed using a SphymoCor Ecel (Atcor Medical) |
Other
| Measure | Time frame | Description |
|---|---|---|
| Change in the composition of the gut microbiota | 4 weeks | Abundance measured using 16 s rRNA sequencing |
Outcome results
None listed