Effects of Vitamin A and Carotenoids on Iron Absorption

Status

Completed

Phases

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT01493297

Enrollment

Registered

2011-12-15

Start date

2011-09-30

Completion date

2012-07-31

Last updated

2014-01-23

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Iron Absorption

Keywords

Retinyl palmitate, beta-carotene, stable isotopes, radio isotopes

Brief summary

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.

Interventions

OTHERLabeled iron solutions

Labeled iron as FeSO4 (4 mg/test meal)

Study design

Allocation

NON_RANDOMIZED

Intervention model

CROSSOVER

Primary purpose

BASIC_SCIENCE

Masking

SINGLE (Subject)

Eligibility

Sex/Gender

FEMALE

Age

18 Years to 52 Years

Healthy volunteers

Yes

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

Design outcomes

Primary

Measure	Time frame	Description
Fractional iron absorption	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.

Countries

Venezuela

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026