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Effects of Avocado When Added to a Meat Patty on Inflammation in Healthy Men

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01397071
Recruitment Status : Completed
First Posted : July 19, 2011
Results First Posted : September 25, 2019
Last Update Posted : September 25, 2019
Information provided by (Responsible Party):
Zhaoping Li, University of California, Los Angeles

Brief Summary:

Avocados are naturally rich in antioxidants, or beneficial compounds, that can help prevent many diseases, like atherosclerosis (hardening of the arteries). When foods that are high in fats are eaten, certain harmful compounds can be absorbed, which can lead to atherosclerosis. One harmful compound is called malondialdehyde, or MDA. This compound can be measured in the blood and the urine after a person eats a high fat meal. Antioxidants found in herbs and spices may lower the absorption of MDA, which could help prevent the development of atherosclerosis.

This study will determine whether the beneficial compounds of avocado can reduce absorption of MDA. This will be tested by asking healthy males to eat a high fat ground beef patty with or without avocado and then measuring the amount of MDA in their blood and urine samples. Blood flow will also be measured. Healthy men have been chosen for this study because eating high fat hamburger patties can easily mimic in them the condition that causes atherosclerosis. Avocados are rich in antioxidants, which have been shown in previous studies to reduce the absorption of harmful compounds, like MDA, that are formed during cooking. The results from this study may help to explain how high fat foods can be harmful to the body and how beneficial antioxidants from herbs and spices can protect the body.

This will be determined from blood and urine samples after the subjects are given two different meals: a) a plain cooked ground beef patty, and b) or avocado with a cooked ground beef patty.

Condition or disease Intervention/treatment Phase
Healthy Volunteers Other: Avocado Not Applicable

Detailed Description:

The Hass Avocado contains monounsaturated fat, lutein, glutathione, vitamin E, and other antioxidants. This study will determine whether avocado exerts a beneficial effect by inhibition of the absorption of malondialdehyde (MDA) which is a measure of lipid peroxidation. In a previous study, we demonstrated that spice antioxidants resulted in a 70 percent decrease in the formation of MDA during cooking and that healthy volunteers consuming burgers made with spice excreted 50 percent less MDA in their urine than subjects consuming a control burger made without spices. Since the spices were added during cooking of the burger, it was not possible to assess the effects of the antioxidants in the stomach. Foods in the stomach continue to form lipid peroxidation products during digestion and this is called the "bioreactor" function of the stomach. In the proposed study known quantities of fresh avocado will be placed on top of a burger prior to consumption to determine whether the avocado inhibits formation of MDA from cooked burger meat in the stomach. Study demonstrated an increase in inflammatory and oxidative markers in mononuclear cells using Western blot analysis of nuclear factor-kappa light chain enhancer of activated B cells (NFkB) and NADPH oxidase subunits following a mixed high calorie meal. Considering the rich content of bioactive compounds in the avocado, we therefore selected these methods for the endpoint determinations as well in this proposed randomized, crossover study.

We will accomplish the following specific aims:

  1. To measure plasma and urine malondialdehyde by high performance liquid chromatography before and over6 hours after consumption of the test burgers with or without fresh avocado added just prior to consumption.
  2. To measure insulin, glucose, triglycerides, tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), Interleukin 8 (IL-8), NFkB activation, nitric oxide and peripheral arterial tonometry after each test burger.

These studies will add to the evidence that antioxidants in a lipid phase can inhibit formation and/or absorption of cytotoxic lipid products such as malondialdehyde. Ultimately, a better understanding of the role of bioactive substances from plant foods such as the avocado may demonstrate the importance of plant-based antioxidants in human health.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 11 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: Hass Avocado Flesh Inhibition of Appearance of Lipid Peroxidation Products When Added to a Ground Beef Patty Consumed by Healthy Volunteers
Study Start Date : August 2011
Actual Primary Completion Date : February 2012
Actual Study Completion Date : August 2012

Arm Intervention/treatment
Active Comparator: Ground Beef Patty with Avocado
Test burgers with fresh avocado added just prior to consumption
Other: Avocado
Fresh Avocado

Active Comparator: Ground Beef Patty without Avocado
Test burgers
Other: Avocado
Fresh Avocado

Primary Outcome Measures :
  1. Change of Endothelial Function by Measurement of Flow-mediated Vasodilation Using the Reactive Hyperemia Index (RHI) [ Time Frame: Baseline and 2 hours post-ingestion ]
    Change from baseline in reactive hyperemia index (RHI) in response to consumption of 250 g beef patty with or without 68 g avocado added at 2 hour post-ingestion. RHI is a measure of endothelial dysfunction using noninvasive peripheral arterial tonometry (PAT). It is a ratio of the post-to-pre occlusion PAT amplitude of the tested arm, divided by the post-to-pre occlusion ratio of the control arm. RHI less than 1.67 is considered sign of endothelial dysfunction and RHI equal to or greater than 1.67 is considered normal function. The possible range of scores is 1 to 3. Increasing score indicates the improvement of coronary endothelial function.

Secondary Outcome Measures :
  1. Change in Inflammation Marker Nuclear Factor of Kappa Light Polypeptide Gene Enhancer in B-cells Inhibitor Alpha (IkB-alpha) [ Time Frame: 0 (baseline) and 3 hours post-ingestion ]
    Change from baseline inflammatory marker IkB-alpha in response to the consumption of 250 g beef patty with or without 68 g avocado added was assessed at 0 (baseline), 1, 2, 3, 4, 5, 6 hours post-ingestion. Baseline and 3 hours post-ingestion was reported.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 35 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • 18 - 35 years old males (inclusive)
  • Non-smokers
  • Must weigh a minimum of 110 pounds
  • Willing to maintain normal activity and eating patterns for the duration of the study
  • Willing to maintain their normal diet for the duration of the study but avoid dairy, avocado and meat products.

Exclusion Criteria:

  • Females
  • Abnormal liver function (aspartate aminotransferase (AST) and alanine aminotransferase (ALT) > 2 x upper limit)
  • Currently taking steroidal drugs
  • Known HIV positive or AIDS
  • Chronic infectious disease
  • Cancer treated within the past two years
  • Participation in a therapeutic research study within 30 days of baseline
  • Consumption of vegetarian diet
  • Allergy or sensitivity to dairy products
  • Allergic to avocado

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01397071

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United States, California
UCLA Center for Human Nutriiton
Los Angeles, California, United States, 90095
Sponsors and Collaborators
University of California, Los Angeles
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Principal Investigator: David Heber, MD, PhD UCLA Center for Human Nutrition
Publications of Results:
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Responsible Party: Zhaoping Li, Professor of Medicine, University of California, Los Angeles Identifier: NCT01397071    
Other Study ID Numbers: HAB-001
First Posted: July 19, 2011    Key Record Dates
Results First Posted: September 25, 2019
Last Update Posted: September 25, 2019
Last Verified: September 2019
Keywords provided by Zhaoping Li, University of California, Los Angeles:
Avocado, antioxidant