Abstract
Micronutrient deficiencies, particularly iron deficiency anemia, remain widespread among school-aged children in the rural highlands of Guatemala, impairing physical growth and cognitive development. This cluster-randomized controlled trial evaluated the effectiveness of integrating flexible point-of-use micronutrient powder (MNP) fortification into an existing national school feeding program on anemia prevalence and cognitive performance. Sixteen primary schools in the department of Quetzaltenango were randomly assigned (1:1) to either an intervention arm (school meals fortified with MNP three days per week for nine months; n = 308 children aged 6–11 years) or a control arm (standard school meals alone; n = 304 children). Primary outcomes included hemoglobin concentrations, anemia prevalence, and cognitive function assessed via Raven’s Standard Progressive Matrices (RSPM) and the WISC-IV Digit Span test. At nine months, anemia prevalence in the intervention group decreased from 41.2% to 16.5%, whereas the control group experienced a modest change from 40.5% to 35.8% (adjusted odds ratio = 0.31, 95% CI: 0.19–0.50, p < 0.001). Children in MNP-fortified schools demonstrated significantly greater improvements in RSPM raw scores (adjusted mean difference: +3.6 points, p = 0.002) and forward digit span scores (+0.8 digits, p = 0.014) relative to controls. Subgroup analysis revealed that cognitive gains were most pronounced among children who were anemic at baseline. School-based MNP fortification is a highly effective, feasible, and scalable public health intervention for reducing anemia and improving cognitive performance among vulnerable rural children in Central America.
