1, calcium supplementation must be added vitamin D. Vitamin D can effectively promote the body’s absorption of calcium, is the golden key to open the door to calcium metabolism, children need 400 international units of vitamin D per day can be. In fact, vitamin D can be synthesized by the body itself, it is recommended that parents take their children to the sun properly; or choose some calcium preparations containing vitamin D. 2, do not take calcium supplements containing phosphorus. The main elements in the manufacture of bones are calcium and phosphorus, which are very closely related to each other. The human body must meet a certain ratio of calcium and phosphorus intake, if too much phosphorus intake, will be formed into insoluble calcium phosphate out of the body. This inevitably leads to the loss of calcium. The Chinese people’s phosphorus intake has been greatly exceeded because of food and water problems. Especially in infancy and early childhood, phosphorus overload can lead to a series of serious consequences. Chinese nutrition experts call: never give infants and young children to take calcium supplements containing phosphorus! 3, magnesium affects the absorption of calcium. Calcium and magnesium are divalent ions, the absorption in the body will have a competitive role. For infants and young children, the body’s magnesium content through food can reach the needs of metabolism, do not need additional supplementation, and excess magnesium can not only affect the absorption and utilization of calcium, but also cause motor dysfunction, it is recommended not to blindly supplement calcium supplements containing magnesium. 4, food to less salt, conducive to the absorption of calcium. Recent studies have found that: calcium and sodium in the renal tubular reabsorption process competition, high sodium intake, the body will reduce the absorption of calcium. The International Health Organization recommends that the daily salt intake of Chinese people should be less than 6g, the less the better for infants and children. Therefore, it is recommended that families who like to eat salty food strictly control the intake of salt in their children’s diet to ensure the absorption and utilization of calcium in their bodies. 5. The effect of phytic acid and oxalic acid in food on calcium. Chinese people mainly eat plant-based foods. Beans and unfermented flour contain phytic acid; some vegetables (spinach, bamboo shoots, beans, wild rice, onions, etc.) contain oxalic acid, which can combine with calcium to form insoluble substances and affect the absorption of calcium.