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.

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

A de-identified dataset will be made available upon request.