Calcium deficiency in infants can be regulated through dietary modification, supplemental calcium and vitamin D, appropriate sun exposure, etc. The specific analysis is as follows. 1. Dietary regulation: Infants’ food is mainly breast milk and formula, breastfed babies, mothers can eat more protein-rich, calcium-rich foods to increase the nutrition in the milk, formula-fed babies can choose to feed high-calcium-containing milk powder. 2. Supplement calcium and vitamin D: When infants have obvious symptoms of calcium deficiency, they can take appropriate calcium supplements under the guidance of a doctor. Vitamin D is good for promoting the absorption of calcium, and it is usually necessary to take vitamin D supplements together with calcium supplements. 3. Appropriate sun exposure: The ultraviolet rays in the sun can promote the synthesis of vitamin D in infants’ bodies, which can help the absorption of calcium, so you can take your baby outdoors to sunbathe when the weather permits.