Intervention Effect of a Soybean-Based Complementary Food Supplement on Anemic Infants in a Poor Rural Region in China: Evidence from Quasi-RCT

Abstract

The soybean-based Yingyang Bao complementary food supplement represents a special nutritional improvement method for anemic infants in many intervention projects across China, while its benefits lack rigorous evidence. Using a quasi-randomized controlled trial design, which adhered to randomization and control except for the blinding method, 248 anemic infants were divided randomly into an intervention group (128 cases received the Yingyang Bao intervention based on routine feeding) and a control group (120 cases only received routine feeding). Anthropometric indicators and 16 blood indicators were measured at baseline and 1 year after intervention. The levels of hemoglobin, 1,25-dihydroxy vitamin D, homocysteine, retinol, vitamin D3, and soluble transferrin receptor and the height–age-Z score and weight–age-Z score of the intervention group were significantly improved after the intervention (p < 0.05). The homocysteine level improvement appeared to be moderately negatively correlated with the cobalamin level improvement (p < 0.05). The improvements of five indicators were significant correlated with the intervention duration (p < 0.05), and the corresponding three significant regression equations could predict the intervention effect and the intervention duration to a certain extent. This quasi-randomized controlled trial provided more convincing evidence that Yingyang Bao can effectively improve three kinds of malnutrition compared to previous research which only adopted self before and after comparison.