Clinical trial NCT00128752: The CARO Study - Bioefficacy of Beta-Carotene in Oil and in a Mixed Diet in Healthy Subjects
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
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Healthy
Keywords: vitamin A
beta Carotene
diet
nutrition
nutritional requirements
Lead sponsor: Radboud University Medical Center
Sponsor class: OTHER
Collaborators: name: Dutch Dairy Organization (NZO)
First posted: 2005-08-10
Enrollment: 24
Sex: ALL
Minimum age (years): 18
Maximum age (years): 50
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: PREVENTION

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.


Eligibility criteria: 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

Primary outcomes:
measure: 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
Secondary outcomes:
Other outcomes:
Locations:
city: Nijmegen
country: Netherlands
facility: Radboud University Nijmegen Medical Centre
state: Gelderland
Study officials:
affiliation: Radboud University Medical Center
name: Ton HJ Naber, MD PhD
role: STUDY_DIRECTOR
affiliation: Radboud University Medical Center
name: Clive E West, PhD DSc
role: PRINCIPAL_INVESTIGATOR
affiliation: Radboud University Medical Center
name: Carolien A Bouwman, MSc
role: STUDY_CHAIR
References:
citation: 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.
citation: 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.
citation: 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.
citation: 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.