The best time for baby calcium supplementation is when the baby shows early symptoms of calcium deficiency, generally speaking the baby will show obvious symptoms of calcium deficiency only when it is about 6 months old. Mothers should determine whether they need to give their babies calcium according to their baby’s performance 1, often manifested as excessive sweating, independent of temperature, especially head sweating after sleep, so that the child’s head constantly rubs the pillow, long after the cranium visible occipital bald circle. 2. Restlessness and irritability, loss of appetite, and crying: they often appear irritable and fidgety during the day. Mental irritability and disinterest in the surrounding environment. And the infant sweats a lot, cries and wakes up easily after falling asleep. 3.After 1 year of age, children show late teething, some children still have not teething at 1.5 years old, delayed closure of the front chimney door, often after 1.5 years old still not closed. 4, square cranium: infants with calcium deficiency may easily lead to high forehead protrusion, forming a square cranium. 5, often have beaded ribs, is due to the lack of vitamin D, rib cartilage hyperplasia, each rib cartilage hyperplasia connected like a string of beads, often compress the lungs, so that the child poor ventilation, easy to suffer from bronchitis, pneumonia. 6, muscle, tendon relaxation: children with serious calcium deficiency, muscle tendon are relaxed. If the abdominal wall muscles, intestinal wall muscles relaxation, can cause the intestinal cavity pneumonia and the formation of abdominal expansion such as frog belly. If the tendons of the spine are relaxed, hunchback may appear, and if the child learns to walk after the age of 1, calcium deficiency may soften the bones and bend the lower limbs with the weight of the body when standing, some of them may have “X” shaped legs and some may have “O” shaped legs, and fractures may easily occur. In general, children with mild calcium deficiency can improve their calcium deficiency symptoms with dietary supplements such as fish, shrimp, kelp, rib soup and vitamin D rich foods such as pig liver, lamb liver and beef liver to promote calcium absorption. If the symptoms are more severe, vitamin D and calcium supplements can be taken under the guidance of a doctor.