Newborns should take milk as their main source of calcium and do not need to take calcium supplements. When complementary foods are added gradually from 6 months after birth, calcium can be supplemented through foods such as meat and eggs. From birth to 28 days after birth, infants are called newborns. Infants within 6 months after birth, especially newborns, should take milk as the main source of calcium, including breast milk and formula milk, which can meet the calcium needs for growth and development. As infants grow older, their digestive functions become more perfect, their milk teeth begin to erupt, and their chewing function increases, so they can start to add complementary foods gradually from 6 months after birth, and the addition of complementary foods needs to follow the principles of from less to more, from thin to thick, from fine to coarse, and from one kind of food to many kinds of food. Calcium can be supplemented through foods such as meat and eggs, which are high in calcium. Calcium can promote the development of teeth and bones, which is beneficial to the healthy growth of infants. Generally, the calcium intake from food can meet the needs of children’s growth and development, so there is no need to take extra calcium supplements, which can be combined with the intake of vitamin D and exposure to sunlight to help the absorption of calcium.