Diets Enriched With Pecans
- Conditions
- ObesityHypercholesterolemia
- Interventions
- Dietary Supplement: Pecan SUBDietary Supplement: Pecan ADD
- Registration Number
- NCT04376632
- Lead Sponsor
- University of Georgia
- Brief Summary
Background: Previous studies report that daily pecan consumption reduces cholesterol in healthy adults while promoting weight maintenance.
Purpose: To examine the impact of daily pecan consumption with and without dietary substitution instructions for an 8-week period on markers of health in adults at risk for cardiovascular disease.
- Detailed Description
This was a single-blind, randomized controlled trial. The investigators recruited subjects with hypercholesterolemia (high blood cholesterol levels) or at higher risk for cardiovascular disease (CVD) (BMI \> 28 kg/m2). Subjects were randomized into one of three groups: (1) the no nut group (CON), (2) pecan ADD (no diet instructions), and (3) pecan SUB (instructions to substitute pecans with isocaloric foods in habitual diet).
There was a screening visit and 3 testing visits: Baseline (visit 1), mid-visit at week 4 (visit 2), and post-visit at week 8 (visit 3). Anthropometrics, questionnaires, and a fasting blood sample were collected at each visit. A subset of participants participated in a saturated fatty acid meal challenge in which additional blood and metabolism measurements were collected.
Hypothesis: The investigators hypothesized that daily pecan consumption would result in significantly greater improvements in blood lipids, metabolism, and appetite compared to the control group. The investigators also hypothesized that pecan ADD group will result in a larger increase in body weight compared to the pecan SUB and control groups.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 124
- Ages 30-75y with higher cholesterol levels or BMI of 28 kg/m2 or greater (A higher cholesterol level is indicated by "Borderline High/Undesirable" in two or more of the variables (total cholesterol 200-239 mg/dL, LDL cholesterol 130-159 mg/dL, triglycerides 150-199 mg/dL) or "High" in either total cholesterol (240 mg/dL and higher) or LDL (160 mg/dL or higher).
- Familial hypercholesterolemia (individuals with LDL levels greater than the 95th percentile or HDL levels lower than the 20th percentile based on age and sex)
- Nut consumption >2 servings/week or tree nut butter consumption >3 servings/week
- Hormone replacement therapy <5 years
- Women who are pregnant or planning to become pregnant
- Regular exercise of >3 hours/week
- Weight gain or loss of >5% of body weight during last 3 months
- Plans to begin a weight loss/exercise regiment
- History of medical or surgical events that could affect digestion or swallowing
- Gastrointestinal surgeries, conditions or disorders
- Chronic or metabolic diseases
- Atherosclerosis, previous myocardial infarction, stroke, cancer
- Fasting blood glucose levels >126 mg/dl
- Blood pressure >180/120 mmHg
- Medication use that affects digestion, absorption, metabolism
- Lipid-lowering medications
- Medications for diabetes or attention deficit disorders (with or without hyperactivity)
- Steroid/hormone therapies
- Individuals on medically prescribed or special diet
- Individuals with food allergies to foods specifically in the study
- Individuals taking fish oil supplements
- Excessive alcohol consumption (greater than 3 drinks/d for men; greater than 2 drinks/d for women)
- Tobacco or nicotine use
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description Pecan SUB Pecan SUB Participants in this group consume 68 g of pecans/d with instructions to substitute pecans with isocaloric foods in the habitual diet. They are also instructed to avoid all other nuts. Pecan ADD Pecan ADD Participants in this group consume 68 g of pecans/d with no additional dietary instructions and avoid all other nuts.
- Primary Outcome Measures
Name Time Method Change in baseline weight at 4 and 8 weeks Baseline, 4 weeks, 8 weeks Weight (kg)
Change in baseline total body fat percentage at 4 and 8 weeks Baseline, 4 weeks, 8 weeks Total body fat percentage (%)
Change in baseline fasting blood lipids at 4 weeks and 8 weeks Baseline, 4 weeks, 8 weeks Total cholesterol (mg/dL), high-density lipoprotein (HDL) cholesterol (mg/dL), triglycerides (mg/dL), low-density lipoprotein (LDL) cholesterol (mg/dL), non-HDL cholesterol (mg/dL), apolipoprotein B (mg/dL)
Change in baseline waist and hip circumference at 4 and 8 weeks Baseline, 4 weeks, 8 weeks waist and hip circumference (cm)
Change in baseline lipoprotein(a), lipoprotein particle number, and lipoprotein size at 4 and 8 weeks Baseline, 4 weeks, 8 weeks Low-density lipoprotein (LDL) particle number (nmol/L), LDL small (nmol/L), LDL medium (nmol/L), HDL large (nmol/L), lipoprotein(a) (nmol/L)
Change in baseline low-density lipoprotein (LDL) peak size at 4 and 8 weeks Baseline, 4 weeks, 8 weeks LDL peak size (angstrom)
- Secondary Outcome Measures
Name Time Method Change in diet respiratory exchange ratio (RER) from baseline to 8 weeks Measured at fasting and for 3.5h postprandially at baseline and 8 weeks RER measured via indirect calorimetry
Change in fasting and postprandial total antioxidant capacity from baseline to 8 weeks Measured at fasting and for 4 hours postprandially at baseline and 8 weeks Total antioxidant capacity (uM trolox equivalents) measured via Oxygen Radical Absorbance Capacity (ORAC) assay.
Change in fasting and postprandial insulin from baseline to 8 weeks Data will be collected at fasting at baseline, 4 weeks and 8 weeks. Postprandial data will be collected at baseline and 8 weeks. Insulin (uU/mL)
Change in fasting and postprandial carbohydrate and fat oxidation from baseline to 8 weeks Measured at fasting and for 3.5h postprandially at baseline and 8 weeks Carbohydrate oxidation (g) and fat oxidation (g) measured via indirect calorimetry
Change in fasting and postprandial peptide YY, cholecystokinin (CCK), and ghrelin from baseline to 8 weeks Data will be collected at fasting at baseline, 4 weeks and 8 weeks. Postprandial data will be collected at baseline and 8 weeks. Peptide YY (pg/mL), CCK (pg/mL) and ghrelin (pg/mL)
Change in fasting and postprandial glucose and triglycerides from baseline to 8 weeks Data will be collected at fasting at baseline, 4 weeks and 8 weeks. Postprandial data will be collected at baseline and 8 weeks. Glucose (mg/dL) and triglycerides (mg/dL)
Change in fasting and postprandial non-esterified free fatty acids (NEFA) from baseline to 8 weeks Data will be collected at fasting at baseline, 4 weeks and 8 weeks. Postprandial data will be collected at baseline and 8 weeks. NEFA (mEq/L)
Change in diet induced thermogenesis (DIT) from baseline to 8 weeks Baseline and 8 weeks DIT (kcals) measured via indirect calorimetry
Change in resting metabolic rate (RMR) from baseline to 8 weeks Baseline and 8 weeks RMR (kcals/d) measured via indirect calorimetry
Change in fasting and postprandial lipid peroxidation from baseline to 8 weeks Measured at fasting and for 4 hours postprandially at baseline and 8 weeks Malondialdehyde (MDA) (uM) measured via Thiobarbituric acid reactive substances (TBARS) assay.
Changes in fasting and postprandial hunger and satiety from baseline to 8 weeks Measured at fasting and for 4 hours postprandially at baseline and 8 weeks. Also, measured once per hour after the baseline and 8-week visits. 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 0-100 mm. Zero represents no hunger, fullness, prospective consumption, and desire to eat, while 100 represents the greatest feeling of these outcomes.
Trial Locations
- Locations (1)
University of Georgia- Department of Foods and Nutrition
🇺🇸Athens, Georgia, United States