Introduction to the Workshop on Current Issues in Feeding the Normal Infant

Gestation and lactation form a biologic continuum during which nutrients, protective factors, and growth modulators are transferred from mother to offspring. Because placental transfer ceases at birth, these placental functions must be maintained by feeding. It has become accepted as axiomatic that breast-feeding by a healthy mother for some time after birth is the biologic norm for the healthy term infant. However, the apparent success of modern commercially prepared formulas in the Western world has raised questions in the minds of some pediatricians and infant nutritionists about this axiom. Certainly, it cannot be argued on teleological grounds alone that because a particular constituent is present in human milk that it is, therefore, needed by the infant. Scientific questions about human milk can be formulated, and the evidence should be subjected to the same scrutiny as any other such question. During this first year of postnatal life, many biochemical adaptations are taking place. Those in the gastrointestinal tract and the immune system are especially important in bridging the transition between gestation and lactation, on the one hand, and independent postnatal life, on the other. In early infancy we must consider the role of human milk v formula and of whey-predominant v caseinpredominant formulas in the light of our newer knowledge of these adaptations. Both in the human and in animals, biochemical adaptations during the fetal and perinatal periods have been more extensively studied than those during the weaning period. Indeed, the data on which to make nutritional judgments during the later periods of infancy are scant.