The Effect of Avocado Consumption on Vascular Health

The Influence of Daily Consumption of Avocado on Biomarkers of Vascular Health

The study will investigate the effect of avocado consumption on markers of vascular health. Sixty participants will be enrolled in the 6-week study. A randomized parallel design will be utilized. Participants will either receive a typical American diet, or a modified typical American diet in which avocado is substituted for foods that contain moderate and high amounts of saturated fat, to allow the isoenergetic inclusion of avocado.

Study Overview

• Status: Completed
• Conditions: Focus: Avocado Consumption & Vascular Health
• Intervention / Treatment: Other: Diet Treatment

• Study Type: Interventional
• Enrollment (Actual): 60
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Maryland
    • Beltsville, Maryland, United States, 20705
      • USDA Beltsville Human Nutrition Research Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 28 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• BMI between 25 and 42 kg/m2
• Age 28 to 70 years during the intervention
• Fasting glucose ≤ 126 mg/dl
• Blood pressure ≤ 160/100 mm Hg

Exclusion Criteria:

• Presence of kidney disease, liver disease, gout, certain cancers, thyroid disease, gastrointestinal, other metabolic diseases, or malabsorption syndromes
• Women who have given birth during the previous 12 months
• Pregnant women or women who plan to become pregnant or become pregnant during the study
• Lactating women
• Type 2 diabetes requiring the use of oral antidiabetic agents or insulin
• History of eating disorders or other dietary patterns which are not consistent with the dietary intervention (e.g., vegetarians, very low fat diets, high protein diets)
• Volunteers who routinely participate in "heavy" exercise or volunteers who initiate an exercise program during the study.
• Volunteers who have lost 10% of body weight within the last 12 months
• Use of prescription or over-the-counter antiobesity medications or supplements (e.g., phenylpropanalamine, ephedrine, caffeine, during and for at least 6 months prior to the start of the study) or history of a surgical intervention for obesity
• Active cardiovascular disease (such as heart attack or procedure within the past three months or participation in a cardiac rehabilitation program within last three months, stroke or history/treatment for transient ischemic attacks in the past three months, or documented history of pulmonary embolus in past six months)
• Smokers or other tobacco users (during the 6 months prior to the start of the study)
• Unable or unwilling to give informed consent or communicate with study staff
• Self-report of alcohol or substance abuse within the past twelve months and/or current acute treatment or rehabilitation program for these problems (Long-term participation in Alcoholics Anonymous is not an exclusion.)
• Other medical, psychiatric, or behavioral factors that in the judgment of the Principal Investigator may interfere with study participation or the ability to follow the intervention protocol.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Typical American Diet; Participants will receive a typical American diet for 6 weeks.	Other: Diet Treatment; Participants will consume a controlled diet for 6 weeks where all meals will be provided by the facility. Participants will be instructed to eat all foods and only foods provided to them.
Experimental: Avocado Diet; Participants will receive a modified typical American diet in which avocado is substituted for foods that contain moderate and high amounts of saturated fat to allow the inclusion of avocado.	Other: Diet Treatment; Participants will consume a controlled diet for 6 weeks where all meals will be provided by the facility. Participants will be instructed to eat all foods and only foods provided to them.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Endothelial Function	Noninvasive endothelial function will be assessed, following a 12-hours fast, by measuring endothelium-dependent flow mediated dilation of the peripheral bed. Participants will then consume a test meal and endothelial function will be assessed again 3 hours later.	0 hr and 3 hr at baseline and after 6 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in Blood Pressure	Blood pressure will be measured using a standardized protocol at the beginning and end of the intervention.	Baseline and after 6 weeks
Change in Gene Expression	Blood samples will be used to test how the intervention affects gene expression. The expression of genes related to cardiovascular disease risk will be measured at the beginning and end of the 6-week intervention (fasted and post-prandially).	Baseline and after 6 weeks
Change in Biomarkers of Cardiovascular Disease Risk	Blood will be collected at the beginning and end of the dietary intervention, following the endothelial function measurements (fasted and post-prandial collections). Blood will be assessed for biomarkers of cardiovascular disease risk, including electrolytes (sodium, potassium, chloride), markers of inflammation (IL-6, IL-10, IL-1 beta, C-reactive protein, TNF-alpha, fibrinogen, ICAM), markers of vascular function (endothelin-1, factor VII, plasminogen), and blood lipid panel (plasma total cholesterol, HDL-cholesterol, LDL-cholesterol, triglycerides).	Baseline and after 6 weeks

Collaborators and Investigators

• Sponsor: USDA Beltsville Human Nutrition Research Center
• Collaborators: Hass Avocado Board

Study record dates

Study Major Dates

• Study Start: April 1, 2012
• Primary Completion (Actual): July 1, 2012
• Study Completion (Actual): July 1, 2012

Study Registration Dates

• First Submitted: February 7, 2012
• First Submitted That Met QC Criteria: May 8, 2012
• First Posted (Estimate): May 10, 2012

Study Record Updates

• Last Update Posted (Estimate): February 24, 2016
• Last Update Submitted That Met QC Criteria: February 23, 2016
• Last Verified: February 1, 2016

More Information

Terms related to this study

• Other Study ID Numbers: HS39