Effectiveness of nutrition interventions for children aged 36–59 months in a suburban preschool in Hanoi, Vietnam

Malnutrition remains a public health concern among preschool children in Vietnam, particularly in suburban areas. School-based interventions may effectively improve dietary intake and growth outcomes. This study evaluated the effectiveness of a structured nutrition intervention on the nutritional status, hemoglobin concentration, and dietary intake of children aged 36–59 months in a suburban preschool in Hanoi. A comparative before-and-after (CBA) design was implemented from January to December 2024 at Viet Hung Kindergarten, Dong Anh Town, Hanoi. Classes were randomly assigned to either the intervention or control group, and outcomes were measured at the child level. The intervention included caregiver and teacher nutrition education, school meal improvement, and promotion of healthy eating. Anthropometric indices, SpHb concentration, micronutrient deficiency symptoms, and dietary intake were assessed before and after the intervention. At baseline, groups were comparable in age, weight, height, and nutritional status (p > 0.05). After 12 months, the intervention group showed greater gains in weight (0.73 ± 0.6 vs. 0.56 ± 0.58 kg, p = 0.0304) and height (2.07 ± 1.01 vs. 1.71 ± 1.26 cm, p = 0.0278). Significant improvements were observed in weight-for-age and height-for-age Z-scores, SpHb concentration (+ 0.8 g/dL, p < 0.001), and reductions in micronutrient deficiency symptoms (p < 0.05). Energy, protein, and calcium intakes increased significantly more in the intervention group than in controls (p < 0.001). The school-based nutrition intervention effectively improved growth, hemoglobin concentration, and dietary intake among preschoolers. These findings support implementing integrated nutrition programs in early childhood education settings in Vietnam.