Efficacy of combined supplementation of vitamins A/D/K1/K2 on the growth and development of preterm infants: A randomized controlled trial

Objective: This study elucidates the effects of additional supplementation of vitamins A and K2 on skeletal development and growth in preterm infants. Methods: This study was a single-center, single-blind, randomized controlled trial. Eighty-six preterm infants were randomized into the control group (who received vitamin D 400 IU/day and K1 20 μg/day) and intervention group (who additionally received vitamin A 1500 IU/day and K2 (MK-7) 50 μg/day for 12 months). Bone mineral density (BMD), height standard deviation score (HtSDS), serum vitamin levels, and adverse events were assessed. Results: After 12 months, the intervention group had higher lumbar spine and femur BMD, greater HtSDS, and higher serum vitamin A, D, K1, K2, and 25-OH-D levels, with statistically significant differences (all P < 0.05). There was no statistically significant difference in the incidence of adverse reactions between groups (P > 0.05). Conclusion: Supplementing vitamins A and K2 alongside routine vitamin D/K1 was associated with significant improvements in skeletal maturity, bone mineral density, and micronutrient status in preterm infants, without affecting safety. © 2026 American Society for Parenteral and Enteral Nutrition.