ĐÁNH GIÁ HIỆU QUẢ CỦA SỮA HỌC ĐƯỜNG LÊN TÌNH TRẠNG DINH DƯỠNG VÀ VI CHẤT Ở TRẺ EM SUY DINH DƯỠNG THẤP CÒI TỪ 24 ĐẾN 59 THÁNG TUỔI TẠI BẮC KẠN

Abstract

Objective: To evaluate the efficacy of supplementing two types of school milk (micronutrient-fortified milk versus unfortified regular milk) on the nutritional status and micronutrient levels (zinc, iron, calcium, vitamin D) among children aged 24-59 months with stunting or at risk of stunting across 8 preschools in Bac Kan Province.

Methods: A cluster-randomized, single-blind controlled clinical trial was conducted over a 4-month intervention period. A total of 237 stunted or at-risk children aged 24-59 months completed the trial (123 in the intervention group receiving 360 mL/day of micronutrient-fortified milk, and 114 in the control group receiving 360 mL/day of regular milk. Anthropometric parameters (height, weight, HAZ, WAZ) were evaluated monthly from baseline (T0) to endline (T4). Serum zinc, iron, total calcium, and 25(OH)D levels were measured at baseline (T0) and endline (T4).

Results: After four months of intervention, both groups receiving school milk supplementation showed improvements in weight, height, WAZ, HAZ, and serum calcium and vitamin D levels. At baseline (T0), anthropometric and biochemical parameters were comparable between the two groups (p > 0,05). After 4 months of intervention, the micronutrient-fortified group demonstrated significantly greater cumulative gains in height (3.30 ± 0.43 cm to 2.69 ± 0.36 cm, p < 0,05) and HAZ score (+0.36 ± 0.11 SD vs. +0.18 ± 0.13 SD, p < 0.05). Statistically significant differences in linear growth emerged starting from the 3rd month (T3). Cumulative weight gain was markedly higher in the intervention group (2.20 ± 0.45 kg vs. 1.44 ± 0.30 kg, p < 0.05), accompanied by a superior WAZ improvement (+0.94 ± 0.21 SD vs. +0.88 ± 0.26 SD, p < 0.05). Serum zinc concentrations increased by 3.33 ± 4.40 µg/dL in the intervention group compared to 0.16 ± 4.46 µg/dL in controls (p < 0.05). Total calcium and 25(OH)D gains were also significantly superior in the intervention arm (+0.55 ± 0.35 mmol/L and +21.66 ± 11.65 ng/mL, respectively, p < 0.05). Serum iron levels showed changes within groups (p > 0.05).

Conclusion: The provision of school milk, whether regular or multi-micronutrient fortified, effectively improved height, weight, Z-scores, and restored the micronutrient (Zinc, Calcium, vitamin D) and hemoglobin status among stunted preschool children in Bac Kan. Notably, multi-micronutrient fortified milk demonstrated greater efficacy than regular milk in improving both anthropometric indices and micronutrient levels.