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Provitamin A Absorption and Conversion With Avocados

This study has been completed.
Hass Avocado Board
Information provided by (Responsible Party):
Jessica Cooperstone, Ohio State University Identifier:
First received: September 4, 2011
Last updated: September 28, 2016
Last verified: September 2016
Vitamin A is necessary in the human diet. The form of vitamin A found in fruits and vegetables is not "active" and must be converted to the active form in the human body. However, information on the ability of humans to absorb and convert vitamin A to the active form is still lacking. In this study, the investigators will observe the absorption and conversion of vitamin A from orange tomato sauce and/or carrots after a meal with fat (from avocado fruit) and a meal without fat. The investigators will also test whether eating these foods might protect the blood against damage that could lead to heart disease.

Condition Intervention
Other: Post-prandial Feeding Study

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Open Label
Primary Purpose: Basic Science
Official Title: Enhancing Human Intestinal Absorption of Carotenoids and Bioconversion of Carotene to Vitamin A in the Presence of Hass Avocados

Resource links provided by NLM:

Further study details as provided by Ohio State University:

Primary Outcome Measures:
  • Post-prandial levels of provitamin A and vitamin A [ Time Frame: Nine post-prandial blood samples will be taken over twelve hours ]
    The absorption of and conversion of provitamin A carotenoids into vitamin A will be measured after the consumption of a carotenoid-rich meal. The meal will be served both with and without avocado as a source of lipid.

Secondary Outcome Measures:
  • post-prandial antioxidant status of blood [ Time Frame: comparing baseline vs. 5 hour status ]
    The ability of a carotenoid-rich meal to reduce the susceptibility of blood lipoproteins to oxidative stress will be tested. A modified trolox equivalent antioxidant capacity (TEAC) assay will be used.

Enrollment: 24
Study Start Date: September 2011
Study Completion Date: March 2012
Primary Completion Date: January 2012 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Tomato Meal
A tomato meal will be fed with and without avocado.
Other: Post-prandial Feeding Study
Carrot Meal
A carrot meal will be fed with and without avocado.
Other: Post-prandial Feeding Study

Detailed Description:

The primary objective of this study will be to demonstrate that adding avocados to a carotene rich meal will promote the absorption of provitamin A carotenoids and enhance the delivery of greater quantities of vitamin A. This objective will be accomplished by quantitation of the immediate post-prandial plasma concentrations of parent carotenoids and vitamin A metabolites after subjects consume a meal with or without avocado in combination with a serving of tomato sauce (containing nutritionally relevant amounts of beta-carotene) or carrots.

The secondary objective of this study will be to determine if higher levels of carotenoids and other antioxidants transported in the bloodstream will have a protective role in promoting cardiovascular health. This objective will be accomplished by testing the oxidation capacity of lipoprotein fractions before and after meal supplementation.


Ages Eligible for Study:   18 Years to 70 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Total cholesterol (140 to 200 mg/dL)
  • BMI 17 to 30
  • Age 18-70 years

Exclusion Criteria:

  • Lactating, pregnant, or plan to be pregnant during study
  • Tobacco use (cigarettes or chewing tobacco)
  • Metabolic disease
  • Malabsorption disorders
  • History of cancer, esophageal, gastric, or intestinal ulcers
  • History of liver or kidney insufficiency or failure
  • Allergies to tomatoes or tomato products
  • Allergies to carrots
  • Allergies to avocados
  • Obesity (BMI>30)
  • Hypercholesterolemia (total cholesterol> 200mg/dL)
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01432210

United States, Ohio
The Ohio State University Clinical Research Center
Columbus, Ohio, United States, 43210
Sponsors and Collaborators
Ohio State University
Hass Avocado Board
Principal Investigator: Steven J Schwartz, Ph.D. Ohio State University
  More Information

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Jessica Cooperstone, Research Scientist, Ohio State University Identifier: NCT01432210     History of Changes
Other Study ID Numbers: 2011H0159
60030575 ( Other Identifier: OSURF )
Study First Received: September 4, 2011
Last Updated: September 28, 2016

Keywords provided by Ohio State University:
post-prandial absorption
provitamin A carotenoids
vitamin A

Additional relevant MeSH terms:
Beta Carotene
Vitamin A
Growth Substances
Physiological Effects of Drugs
Molecular Mechanisms of Pharmacological Action
Protective Agents processed this record on March 24, 2017