Protein intake and energy requirements of the infant.

Abstract

R ecommended nutrient intakes of term infants are based, largely, on the intakes of various nutrients ingested by normally growing, breast-fed infants. However, there is no such standard for prematurely born and/or low-birthweight (LBW) infants. Most of these infants cannot be breast-fed for the first several weeks after birth and, even if this were possible, it is not clear that the relatively lower growth rate achievable with human milk versus that achievable with artificial formulas is appropriate for the LBW infant. Moreover, while there is general agreement that nutrient intakes sufficient to support some arbitrary rate of weight gain are necessary, the magnitude of the rate of weight gain that should be achieved is less clear. The LBW infant’s immature metabolic capacity is an additional factor that must be considered in reaching recommendations concerning the desirable intakes of various nutrients, particularly protein. While most investigators agree that intakes likely to result in “significant” metabolic derangements are undesirable, it usually is difficult to define a significant metabolic derangement. In this report, the current knowledge and opinions concerning the nutritional goals and, hence, the protein and energy needs of the LBW infant are summarized. Discussion of protein needs begin with a brief historical review of several sets of data that have been cited over roughly the past half-century to support a variety of oftenconflicting concepts. This is followed by discussions of more recent concepts of protein needs and a variety of factors that may influence protein needs. The energy needs of the LBW infant are discussed much more briefly. While suggestions