The manifestations and symptoms of calcium deficiency in children vary according to the time and degree of calcium deficiency. Common manifestations and symptoms include bone deformities, slow growth and poor sleep quality. 1. Bone deformity: Calcium is an indispensable nutrient for bone development. Insufficient intake of calcium will easily lead to abnormal bone development, resulting in the appearance of “X”-shaped legs or “O”-shaped legs in children. 2. Slow growth and development: Calcium is an essential nutrient for children’s growth and development, and children with calcium deficiency have slower growth and development compared to other children. 3. Poor sleep quality: Calcium deficiency can easily cause muscle spasms and bone pain, which makes children wake up easily during night sleep, thus affecting their sleep quality. Parents should give their children more calcium-rich foods in moderation, such as dairy products, soy products, meat, etc., and eat more vitamin-rich vegetables and fruits to help calcium absorption. If necessary, you need to go to the hospital to consult with the doctor’s advice, and use the appropriate medication to give your child calcium supplements.