Children need to take vitamin D supplements to be able to promote calcium absorption, but natural foods contain low levels of vitamin D. Animal foods are the main source of natural vitamin D, such as sea fish, shellfish, animal offal, egg yolk and cream, which contain high levels, while lean meat, nuts, vegetables and fruits contain small doses of vitamin D. In addition to supplementing the body’s vitamin D needs through the intake of the above foods in daily life, it is also necessary to take medication containing vitamin D to supplement it. In addition, it is also necessary to do a moderate amount of outdoor exercise, through the sun to promote the body’s own synthesis of vitamin D, which is also conducive to promoting the absorption of calcium.