Effects of Vitamin A and Carotenoids on Iron Absorption

The objective of this study is to investigate the effect of vitamin A and carotenoids on iron absorption in healthy subjects with low and normal vitamin A status. Vitamin A and carotenoids have been reported to enhance the nonheme iron absorption, but the results from human isotope studies are equivocal. Radio-iron studies in Venezuelan adults have consistently reported an increase in iron absorption, whereas stable and radio isotopes studies conducted in Sweden and Switzerland reported no influence. Differences in vitamin A status of the subjects may be a possible explanation for the contradictory findings. In this study, iron absorption will be measured from an iron-fortified maize bread meal with or without retinyl palmitate or β-carotene by using both stable- and radioactive-isotope techniques in Venezuelan women with a range of vitamin A status.

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Key information

Conditions

Iron Absorption

Age range

18 year–52 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Venezuelan Institute for Scientific Research (IVIC)

Caracas, 1020-A, Venezuela

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

Women 18-52 years old
Body weight ≤ 70 kg
Body mass index (BMI), 18.5-30 kg/m2
Adequate vitamin A status (SR ≥ 0.7 μmol/L, n=20)
Inadequate vitamin A status (SR < 0.7 μmol/L, n=20)
No major medical illnesses (no known infection, gastrointestinal or metabolic disorders)

Exclusion criteria

Pregnancy or lactation
Regular intake of medication (except oral contraceptives)
Blood donation or significant blood loss (accident, surgery) over the past 4 months
Currently participating in another clinical trial or having participated in another clinical trial during the last 3 months prior to the beginning of this study
Former participation in a study involving administration of iron stable isotopes

Treatment and study plan

Labeled iron solutions

Other

Labeled iron as FeSO4 (4 mg/test meal)

Primary outcomes

Fractional iron absorption

Time frame: 1 month after enrollment

Iron absorption will be estimated by measuring the erythrocyte incorporation of stable (57Fe/58Fe) and radio (55Fe/59Fe) iron isotopes labels given in test meals.

Sponsors and collaborators

Lead sponsor

Swiss Federal Institute of Technology

Other

Collaborators

Instituto Venezolano de Investigaciones Cientificas

Registry information

Important dates

Study start: 2011
Primary completion: 2011
Study completion: 2012
First posted: Dec 15, 2011
Registry last updated: Jan 23, 2014

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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Completed