Psychosocial Aspects of Breast-Feeding

Abstract

For many years, bottle-feeding has been the primary method of nurturing infants. Social pressures and public health sanctions have continued to foster this trend. Recent evidence suggests, however, that there are distinct advantages to breast-feeding when compared to bottle-feeding.¹ More specifically, the biochemical and immunologic constituents of human milk confer a uniqueness and species-specificity not achieved in commercial milk preparations or cow’s milk.² Biochemical uniqueness is demonstrated by difference in amino acid levels, such as elevated taurine and cystine and lowered tyrosine and phenylalanine concentrations,^3,4 the absence of sensitizing proteins such as β-lactoglobulin, and a greater proportion of proteins of high biologic value in the whey fraction of human milk.⁵ Not only are protein constituents unique, but lipid fractions also differ from other mammalian milks. Human milk contains greater amounts of 2-monoglycerides, thereby enhancing fat absorption.⁶ Human milk also contains a lipase that preferentially liberates fatty acids from the 1- and 3-positions in order to facilitate absorption.⁷ Finally, many biochemical constituents of human milk have interdependent interactions. For example, both human and cow’s milks contain similar iron and zinc concentrations; however, absorption of both minerals is more effective in human milk.^8,9 In addition to these biochemical features, human milk contains many immunologic factors that provide protection against illness in the young infant.^10,11