The Effect of One Avocado Per Day on Established and Emerging Cardiovascular Disease (CVD) Risk Factors
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- Penn State University
- Enrollment
- 54
- Locations
- 1
- Primary Endpoint
- Lipids and lipoproteins
Study Overview
Brief Summary
The investigators propose to evaluate the effects of avocado consumption (by incorporating 1 unit of fruit per day into a healthy diet) on multiple cardiovascular disease (CVD) risk factors. The investigators will compare chronic consumption of a moderate fat blood cholesterol-lowering diet incorporating one avocado per day versus a blood cholesterol-lowering Lower-Fat diet on established CVD risk factors including lipids and lipoproteins, and blood pressure (BP). The investigators also will evaluate the effects of an avocado diet on several emerging CVD risk factors. To elucidate the specific benefits of avocado and its accompanying bioactives on the aforementioned risk factors, the investigators will compare the avocado diet with a diet that has the same macronutrient profile (but without the avocado).
Detailed Description
A randomized, 3-period cross-over, controlled feeding study was designed to compare the effects of a moderate fat blood cholesterol-lowering diet that provides one avocado per day (total fat = 34% total energy, MUFA=18%, SFA <7%) to an Average American diet (AAD), Lower-Fat diet (total fat = 24% total energy, SFA <7%), and Moderate Fat diet (with equivalent fatty acid profile to the avocado diet) without avocado. The study population consists of 40 overweight (BMI25-35 kg/m2) men and women with moderately elevated LDL-C, between the25-90th percentiles from NHANES. The investigators hypothesize that a moderate fat heart-healthy diet, including 1 avocado per day will reduce CVD risk factors including lipids, lipoproteins, apolipoproteins, lipoprotein particle size, markers of oxidative stress and inflammation, blood pressure and reverse cholesterol transport compared to an AAD, Lower-Fat diet, and moderate fat diet without avocado.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Prevention
- Masking
- None
Eligibility Criteria
- Ages
- 21 Years to 70 Years (Adult, Older Adult)
- Sex
- All
- Accepts Healthy Volunteers
- No
Inclusion Criteria
- •healthy non-smoking
- •overweight (BMI 25-35 kg/m2) men and women
- •LDL-C between the25-90th percentile from NHANES: 105-194mg/dL for males; 98-190mg/dL for females)
Exclusion Criteria
- •BP >140/90 mmHg;
- •A history of myocardial infarction, stroke, diabetes mellitus, liver disease, kidney disease, and thyroid disease (unless controlled on medication);
- •Lactation, pregnancy, or desire to become pregnant during the study;
- •Cholesterol-lowering medication use;
- •Intake of putative cholesterol-lowering supplements (psyllium, fish oil capsules, soy lecithin, niacin, fiber, flax, and phytoestrogens, stanol/sterol supplemented foods);
- •Vegetarianism;
- •Nut allergies (Other food allergies were reviewed on a case-by-case basis);
- •Refusal to discontinue nutritional supplements, herbs or vitamins
Arms & Interventions
Lower-Fat Diet
The Lower-Fat diet will provide ~24% of calories from fat and meet the SFA and cholesterol recommendations of a Step-II diet recommended by the National Heart, Lung, and Blood Association's National Cholesterol Education Program. SFA will provide 7% of calories, and cholesterol will be less than 200mg/day. Vegetables and fruits in the Lower-Fat diet will be selected from foods that are low in antioxidants.
Intervention: Lower-Fat Diet (Other)
Moderate Fat Diet
This diet is designed to be the control diet for the avocado diet and will have an identical fatty acid profile. MUFA-enriched food (fats) will be substituted for avocado. The substitution foods will not contain antioxidant or cholesterol-lowering components similar to those in avocado.
Intervention: Moderate Fat Diet (Other)
Avocado Diet
The avocado diet will be designed to ensure that all subjects incorporate 1 avocado (~136g) per day into a moderate fat diet. Both the Lower-Fat diet and avocado diet will be matched for SFA and dietary cholesterol, but will differ in total fat, primarily MUFA as provided by the avocado. The moderate fat plus avocado diet will provide 34% of calories from total fat, 18% calories from MUFA, and 9% calories from PUFA.
Intervention: Avocado Diet (Other)
Outcomes
Primary Outcomes
Lipids and lipoproteins
Time Frame: The end of each diet period
Total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides are measured as part of the lipids and lipoprotein profile. Diet period one runs for 5 weeks after a 2-week run-in diet, then there is a 2-3 week compliance break, and then diet period two runs for another 5 weeks; then there is a 2-3 week compliance break, and then diet period three runs for another 5 weeks
Lipoprotein particle size
Time Frame: The end of each diet period
Advanced lipoprotein testing is used to measure LDL particle size and subclasses of HDL and VLDL. Diet period one runs for 5 weeks after a 2-week run-in diet (baseline), then there is a 2-3 week compliance break, and then diet period two runs for another 5 weeks; then there is a 2-3 week compliance break, and then diet period three runs for another 5 weeks
Secondary Outcomes
- Inflammatory biomarkers(The end of diet period)
- Oxidized-LDL(The end of each diet period)
- HDL anti-inflammatory function(The end of each diet period)
- Macrophage Cholesterol efflux(The end of each diet period)
- lipid hydroperoxide(The end of each diet period)
- Serum fatty acid profile(The end of each diet period)