Iron, zinc, calcium, copper, magnesium five-element is the bases toguarantee the normal growth and development of the preschool children. Theaim of this article is to comprehensively understand the current state of thefive elements in the pre-school children’s blood and their influence on thepre-school children’s growth in Tanggu District, Tianjin. The five elementsnormal reference range should also be established for the children aged 3-6 inthis region. It would provide a basis for guiding parents and chil...