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.

Study Overview

• Status: Completed
• Conditions: Iron Absorption
• Intervention / Treatment: Other: Labeled iron solutions

• Study Type: Interventional
• Enrollment (Actual): 25
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Venezuela
  • Caracas, Venezuela, 1020-A
    • Venezuelan Institute for Scientific Research (IVIC)

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 52 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Female

Description

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

Study Plan

How is the study designed?

Design Details

• Primary Purpose: BASIC_SCIENCE
• Allocation: NON_RANDOMIZED
• Interventional Model: CROSSOVER
• Masking: SINGLE

Number of Arms

2

Arms and Interventions

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

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: Swiss Federal Institute of Technology
• Collaborators: Instituto Venezolano de Investigaciones Cientificas
• Investigators: Principal Investigator: Maria Andersson, Dr, Swiss Federal Institute of Technology, ETH Zurich

Publications and helpful links

General Publications

• Walczyk T, Davidsson L, Rossander-Hulthen L, Hallberg L, Hurrell RF. No enhancing effect of vitamin A on iron absorption in humans. Am J Clin Nutr. 2003 Jan;77(1):144-9. doi: 10.1093/ajcn/77.1.144.
• Garcia-Casal MN, Layrisse M, Solano L, Baron MA, Arguello F, Llovera D, Ramirez J, Leets I, Tropper E. Vitamin A and beta-carotene can improve nonheme iron absorption from rice, wheat and corn by humans. J Nutr. 1998 Mar;128(3):646-50. doi: 10.1093/jn/128.3.646.
• Garcia-Casal MN. Carotenoids increase iron absorption from cereal based food in the human. Nutr Res 2006;26:340-4.
• Layrisse M, Garcia-Casal MN, Solano L, et al. The role of vitamin A on the inhibitors of nonheme iron absorption: preliminary results. J Nutr Biochem 1997;8:61-7.

Study record dates

Study Major Dates

• Study Start: September 1, 2011
• Primary Completion (ACTUAL): November 1, 2011
• Study Completion (ACTUAL): July 1, 2012

Study Registration Dates

• First Submitted: November 29, 2011
• First Submitted That Met QC Criteria: December 13, 2011
• First Posted (ESTIMATE): December 15, 2011

Study Record Updates

• Last Update Posted (ESTIMATE): January 23, 2014
• Last Update Submitted That Met QC Criteria: January 22, 2014
• Last Verified: January 1, 2014

More Information

Terms related to this study

• Keywords: Retinyl palmitate, beta-carotene, stable isotopes, radio isotopes
• Other Study ID Numbers: ETH-FeVZ