Guatemala Biofortified Maize Study

Absorption of Zinc and Iron From Nixtamalized Biofortified Maize in School-aged Children in Guatemala

Zinc (Zn) and iron (Fe) deficiencies are common in Guatemala, and maize is a staple food throughout the country. The primary aim of this study is to demonstrate if utilizing nixtamalized biofortified maize has the potential to increase dietary Zn and Fe intake and improve the amount of Zn and Fe absorbed when compared to diets incorporating traditional maize (control). This is a randomized, double blinded, comparison study of biofortified vs control maize prepared as tortillas from nixtamalized masa. This study will enroll up to 56 school aged children (10-14 yrs old) living in agricultural communities in the Western Highlands of Guatemala (28/group x 2 groups). Researchers will utilize Zn and Fe stable isotopes to measure total absorbed Zn and Fe. Participants will be active in the study for 27 days. During this time, they will have anthropometric measurements taken and collect 2 blood samples, 1 stool sample, and 9 urine samples.

Study Overview

• Status: Completed
• Conditions: Iron Absorption; Zinc Absorption
• Intervention / Treatment: Other: Biofortified maize; Other: Placebo

• Study Type: Interventional
• Enrollment (Actual): 56
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Guatemala
  • Departamento de Guatemala
    • Guatemala City, Departamento de Guatemala, Guatemala, 1188
      • Institute of Nutrition of Central America and Panama

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: Yes

Description

Inclusion criteria:

• 10-14 years old school children (male and female sex)
• BMI between10-85%tile
• Typically eat homemade tortillas at each meal every day

Exclusion criteria:

• Taking iron or zinc supplements
• Hemoglobin less than 12.9 g/dl for children 10-11 yrs old and less than13.4 g/dl for children 12-14 yrs old (Per the WHO's 2024 publication hemoglobin cut-offs for identifying anemia are 5-11 yrs: less than 11.5 g/dl; 12-14 yrs: less than 12.0 g/dl. To adjust for the elevation of Tecpán at 2254 m, 1.4 g/dl is added to the cut-off point.)
• Girls who are having a menstrual period during the metabolic studies

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Biofortified maize; Children consume biofortified maize that has been traditionally bred to have higher amounts of iron and zinc. Children consume the biofortified maize via 10-15 tortillas a day for 3 days.	Other: Biofortified maize; Maize that has been grown to have higher amounts of iron and zinc.
Placebo Comparator: Traditional Maize; Children consume traditional maize that has lower amounts of iron and zinc compared to the biofortified maize. Children consume the maize via 10-15 tortillas a day for 3 days.	Other: Placebo; Traditional maize

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Total absorbed iron (TAI) (mg)	Total absorbed iron from the diet = fractional absorption of iron x total dietary iron (mg)	2 days
Total absorbed zinc (TAZ) (mg)	Total zinc absorbed from the diet = fractional absorption of zinc x total dietary zinc (mg)	1 day

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma C-reactive protein (CRP) (mg/dL)	CRP is used to measure systemic inflammation	1 day
Plasma zinc concentration (mcg/dL)	Plasma zinc concentration is used to assess zinc status	1 day
Plasma Alpha(1)-acid glycoprotein (AGP) (mg/dL)	AGP is used to measure systemic inflammation	1 day

Collaborators and Investigators

• Sponsor: University of Colorado, Denver
• Collaborators: Institute of Nutrition of Central America and Panama; Semilla Nueva
• Investigators: Principal Investigator: Nancy F Krebs, MD, MS, University of Colorado, Denver

Study record dates

Study Major Dates

• Study Start (Actual): July 31, 2024
• Primary Completion (Actual): February 28, 2026
• Study Completion (Actual): February 28, 2026

Study Registration Dates

• First Submitted: September 4, 2024
• First Submitted That Met QC Criteria: October 18, 2024
• First Posted (Actual): October 21, 2024

Study Record Updates

• Last Update Posted (Actual): May 8, 2026
• Last Update Submitted That Met QC Criteria: May 4, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: stable isotope; Guatemala; maize; biofortification; school-aged children
• Additional Relevant MeSH Terms: Skin Diseases; Keratosis; Skin and Connective Tissue Diseases; Callosities
• Other Study ID Numbers: 24-1030; 7200AA23FA00027 (Other Grant/Funding Number: U.S. Agency for International Development); 261570 (Other Grant/Funding Number: GiveWell)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: A de-identified dataset will be made available upon request.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No