The Effect of Avocado on Cardiovascular Disease (CVD) Risk Factors

Study Overview
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Brief Summary
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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
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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.

Official Title
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The Effect of One Avocado Per Day on Established and Emerging Cardiovascular Disease (CVD) Risk Factors

Conditions
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Cardiovascular Disease, Hyperlipidemia

Intervention / Treatment
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* Other: Avocado Diet
* Other: Lower-Fat Diet
* Other: Moderate Fat Diet


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 21 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Lower-Fat Diet<br>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. | Other: Lower-Fat Diet<br>* 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.<br>* Other names: lower-fat,low SFA diet;|
| Active Comparator: Moderate Fat Diet<br>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. | Other: Moderate Fat Diet<br>* 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.<br>* Other names: moderate fat without avocado;|
| Experimental: Avocado Diet<br>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. | Other: Avocado Diet<br>* 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.<br>* Other names: moderate fat plus avocado;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Lipids and lipoproteins | 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 | The end of each diet period | 
| Lipoprotein particle size | 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 | The end of each diet period | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Oxidized-LDL | 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 | The end of each diet period | 
| lipid hydroperoxide | 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 | The end of each diet period | 
| Macrophage Cholesterol efflux | 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 | The end of each diet period | 
| HDL anti-inflammatory function | 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 | The end of each diet period | 
| Serum fatty acid 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 | The end of each diet period | 
| Inflammatory biomarkers | CRP and IL-6 are measured as the markers of inflammation. 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 | The end of diet period | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein, reverse cholesterol transport