Cardiovascular Disease, Hyperlipidemia
Conditions
Keywords
cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein, reverse cholesterol transport
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.
Interventions
OTHERAvocado 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.
OTHERLower-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.
OTHERModerate 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.
Sponsors
Hass Avocado Board
Penn State University
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
21 Years to 70 Years
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Lipids and lipoproteins | 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 | 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
| Measure | Time frame | Description |
|---|---|---|
| Macrophage Cholesterol efflux | The end of each diet period | 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 |
| HDL anti-inflammatory function | The end of each diet period | 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 |
| Oxidized-LDL | The end of each diet period | 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 |
| Inflammatory biomarkers | The end of diet period | 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 |
| Serum fatty acid profile | The end of each diet period | 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 |
| lipid hydroperoxide | The end of each diet period | 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 |
Countries
United States
Outcome results
None listed