Prof. Dai Yaohua: “When taking calcium supplements, is it necessary to also take vitamin D. Vitamin D can promote calcium absorption. The following three categories are common in our children: insufficient vitamin D alone, calcium deficiency alone, and both vitamin D and calcium deficiency. In terms of our dietary situation, we believe that most children are deficient in both vitamin D and calcium.” “For the above problems, we suggest that children supplementing calcium should also supplement vitamin D. In addition, for the prevention and treatment of rickets, we believe that Chinese children also need to supplement both vitamin D and calcium. Compared to the United States and other regions, our children are less likely to consume foods high in calcium, such as cheese. Therefore, unlike the United States, where only vitamin D supplementation is recommended to prevent rickets on the premise of balanced calcium intake, Chinese children should be supplemented with both vitamin D and calcium to prevent rickets.