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

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.

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Key information

Conditions

Healthy

Age range

18 year–50 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Radboud University Nijmegen Medical Centre

Nijmegen, Gelderland, 6500HB, Netherlands

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

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

Behavioral

Primary outcomes

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

Sponsors and collaborators

Lead sponsor

Radboud University Medical Center

Other

Collaborators

Dutch Dairy Organization (NZO)

Registry information

Official study 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

Important dates

Study start: 2003
Study completion: 2003
First posted: Aug 10, 2005
Registry last updated: Aug 29, 2005

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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