The CARO Study - Bioefficacy of Beta-Carotene in Oil and in a Mixed Diet in Healthy Subjects

This study has been completed.
Dutch Dairy Organization (NZO)
Information provided by:
Radboud University Identifier:
First received: August 9, 2005
Last updated: August 26, 2005
Last verified: August 2005

A controlled dietary intervention study will be carried out based on the stable isotope method the investigators have developed to quantify both the absorption of beta-carotene and its bioconversion to retinol in oil and in a mixed diet. For 6 weeks the participants will consume 2 capsules/day, 7 days/week with each capsule containing 50-mg [13C10] beta-carotene and 50-mg [13C10] retinyl palmitate. For three weeks they will consume a diet with high levels of beta-carotene in vegetables and fruits and for the other 3 weeks they will consume a diet with low levels of beta-carotene in vegetables and fruits supplemented with an extra amount of beta-carotene in oil. Samples of blood and faeces will be taken.

The study hypothesis is that the absorption of beta-carotene in oil in comparison with the absorption of beta-carotene in a mixed diet differs by a factor of 3 to 6. The investigators want to measure the influence of the food matrix of vegetables and fruits on the absorption of beta-carotene in healthy humans on a western diet.

Condition Intervention
Behavioral: absorption and conversion of beta-carotene in human gastrointestinal (GI) tract

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Bio-availability Study
Intervention Model: Crossover Assignment
Masking: Open Label
Primary Purpose: Prevention
Official Title: Bioefficacy and Bioavailability of Beta-Carotene in Oil and in a Mixed Diet in Healthy Subjects Measured Using Specifically 13C-Labelled Beta-Carotene and Retinol

Resource links provided by NLM:

Further study details as provided by Radboud University:

Primary Outcome Measures:
  • levels of retinol and carotenoids and the degree of isotopic enrichment in serum (fasting blood sample) and in faeces (72 hour collection) at the start and at the end of each of the 3-week periods

Estimated Enrollment: 24
Study Start Date: March 2003
Estimated Study Completion Date: October 2003

Ages Eligible for Study:   18 Years to 50 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Men and women between 18 and 50 years old
  • Body mass index (BMI) between 18 and 25 kg/m2
  • Willing to consume the controlled diet and not consume other food items
  • Willing to consume the cooked meal at the research facility and the bread meals and snacks at home (distributed to the participants)
  • Willing to consume the capsules every day

Exclusion Criteria:

  • Hematological diseases and chronic diseases including cancer, renal insufficiency, liver disease, diagnosed gastrointestinal disorders, or surgery of the gastrointestinal tract
  • Use of (oral) drugs suspected of interfering with fat-soluble-vitamin absorption
  • Smoking
  • Excessive alcohol consumption (>30 g/d)
  • Consumption of vitamin or carotenoid supplements 6 weeks before and during the study
  • Not too low or high levels of serum beta-carotene and retinol
  • Normal hemoglobin, hemocytometry, creatinine, ALAT, alkaline phosphatase, and cholesterol blood values (compared with laboratory references)
  • Pregnancy
  Contacts and Locations
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Please refer to this study by its identifier: NCT00128752

Radboud University Nijmegen Medical Centre
Nijmegen, Gelderland, Netherlands, 6500HB
Sponsors and Collaborators
Radboud University
Dutch Dairy Organization (NZO)
Study Director: Ton HJ Naber, MD PhD Radboud University
Principal Investigator: Clive E West, PhD DSc Radboud University
Study Chair: Carolien A Bouwman, MSc Radboud University
  More Information

Additional publications automatically indexed to this study by Identifier (NCT Number): Identifier: NCT00128752     History of Changes
Other Study ID Numbers: CARO-2002-12-12-NZO, NZO-2002-07
Study First Received: August 9, 2005
Last Updated: August 26, 2005
Health Authority: Netherlands: The Central Committee on Research Involving Human Subjects (CCMO)

Keywords provided by Radboud University:
vitamin A
beta Carotene
nutritional requirements

Additional relevant MeSH terms:
Beta Carotene
Growth Substances
Molecular Mechanisms of Pharmacological Action
Pharmacologic Actions
Physiological Effects of Drugs
Protective Agents
Vitamins processed this record on October 22, 2014