Evaluating the student nutrition improvement program: regional disparities and nutritional trends in Yunnan, China (2019–2023)

While the NNIP-RCES effectively enhanced physical growth and alleviated Vitamin A deficiency, persistent anemia, unchanged Vitamin D levels, and marked regional disparities underscore critical areas requiring further attention. Future policy refinements should focus on targeted interventions addressing anemia prevention, Vitamin D supplementation, enhanced dietary diversity, and equitable resource allocation across regions. Strengthened monitoring frameworks and comprehensive nutrition education initiatives are also recommended to ensure sustainable improvements and serve as a model for global school-based nutritional interventions.