Effects of Vitamin A and Carotenoids on Iron Absorption

Study Overview
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Brief Summary
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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.

Official Title
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Effects of Vitamin A and Carotenoids on Iron Absorption

Conditions
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Iron Absorption

Intervention / Treatment
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* Other: Labeled iron solutions


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 52 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Non-Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Retinyl palmitate<br>Labeled iron as FeSO4 (4 mg) added to a test meal with or without retinyl palmitate (1000 RE) | Other: Labeled iron solutions<br>* Labeled iron as FeSO4 (4 mg/test meal)<br>|
| Other: Beta-carotene<br>Labeled iron as FeSO4 (4 mg) added to a test meal with or without beta-carotene (1000 RE) | Other: Labeled iron solutions<br>* Labeled iron as FeSO4 (4 mg/test meal)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fractional iron absorption | 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. | 1 month after enrollment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Retinyl palmitate, beta-carotene, stable isotopes, radio isotopes