NCT00128752

Brief Summary

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.

Trial Health

87
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
24

participants targeted

Target at P25-P50 for not_applicable healthy

Timeline
Completed

Started Mar 2003

Geographic Reach
1 country

1 active site

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

Click on a node to explore related trials.

Study Timeline

Key milestones and dates

Study Start

First participant enrolled

March 1, 2003

Completed
7 months until next milestone

Study Completion

Last participant's last visit for all outcomes

October 1, 2003

Completed
1.9 years until next milestone

First Submitted

Initial submission to the registry

August 9, 2005

Completed
1 day until next milestone

First Posted

Study publicly available on registry

August 10, 2005

Completed
Last Updated

August 29, 2005

Status Verified

August 1, 2005

First QC Date

August 9, 2005

Last Update Submit

August 26, 2005

Conditions

Healthy

Keywords

vitamin Abeta Carotenedietnutritionnutritional requirements

Outcome Measures

Primary Outcomes (1)

  • 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

Interventions

absorption and conversion of beta-carotene in human gastrointestinal (GI) tractBEHAVIORAL

Eligibility Criteria

Age18 Years - 50 Years
Sexall
Healthy VolunteersYes
Age GroupsAdult (18-64)

You may qualify if:

  • 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

You may not qualify if:

  • 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

Contact the study team to confirm eligibility.

Sponsors & Collaborators

Study Sites (1)

Radboud University Nijmegen Medical Centre

Nijmegen, Gelderland, 6500HB, Netherlands

Location

Related Publications (4)

  • van Lieshout M, West CE, Muhilal, Permaesih D, Wang Y, Xu X, van Breemen RB, Creemers AF, Verhoeven MA, Lugtenburg J. Bioefficacy of beta-carotene dissolved in oil studied in children in Indonesia. Am J Clin Nutr. 2001 May;73(5):949-58. doi: 10.1093/ajcn/73.5.949.

    PMID: 11333850BACKGROUND

  • van Lieshout M, West CE, van Breemen RB. Isotopic tracer techniques for studying the bioavailability and bioefficacy of dietary carotenoids, particularly beta-carotene, in humans: a review. Am J Clin Nutr. 2003 Jan;77(1):12-28. doi: 10.1093/ajcn/77.1.12.

    PMID: 12499318BACKGROUND

  • West CE, Eilander A, van Lieshout M. Consequences of revised estimates of carotenoid bioefficacy for dietary control of vitamin A deficiency in developing countries. J Nutr. 2002 Sep;132(9 Suppl):2920S-2926S. doi: 10.1093/jn/132.9.2920S.

    PMID: 12221270BACKGROUND

  • Van Loo-Bouwman CA, West CE, van Breemen RB, Zhu D, Siebelink E, Versloot P, Hulshof PJ, van Lieshout M, Russel FG, Schaafsma G, Naber TH. Vitamin A equivalency of beta-carotene in healthy adults: limitation of the extrinsic dual-isotope dilution technique to measure matrix effect. Br J Nutr. 2009 Jun;101(12):1837-45. doi: 10.1017/S0007114508131762. Epub 2008 Nov 24.

    PMID: 19025719DERIVED

MeSH Terms

Interventions

Absorption

Intervention Hierarchy (Ancestors)

Physical PhenomenaChemical PhenomenaMetabolismPharmacokineticsPharmacological and Toxicological PhenomenaPhysiological Phenomena

Study Officials

  • Ton HJ Naber, MD PhD

    Radboud University Medical Center

    STUDY DIRECTOR

  • Clive E West, PhD DSc

    Radboud University Medical Center

    PRINCIPAL INVESTIGATOR

  • Carolien A Bouwman, MSc

    Radboud University Medical Center

    STUDY CHAIR

Study Design

Study Type
interventional
Phase
not applicable
Allocation
RANDOMIZED
Masking
NONE
Purpose
PREVENTION
Intervention Model
CROSSOVER
Sponsor Type
OTHER

Study Record Dates

First Submitted

August 9, 2005

First Posted

August 10, 2005

Study Start

March 1, 2003

Study Completion

October 1, 2003

Last Updated

August 29, 2005

Record last verified: 2005-08

Locations

NL(1)