Nutrient Intake and Growth Performance of Older Infants Fed Human Milk

Abstract

Study objective: To determine whether the ad libitum addition of solid foods to the diet of exclusively human milk-fed infants will increase energy intake and reverse the decline in weight-for-age percentiles observed during the exclusive breast-feeding period. Design: Weekly or biweekly measures of growth were made longitudinally on a cohort of infants from birth to 36 weeks of age, and monthly measures of nutrient intake were made from 16 weeks of age until 10 weeks after solid foods were introduced into the diet. Subjects: Volunteer mother-infant pairs from middle and upper income groups who met entry criteria, including the intention to breast-feed exclusively for at least for 16 weeks; 58 pairs entered and 45 pairs completed the study. Intervention : Solid foods were introduced at a time determined by the mother and the pediatrician; solid foods from controlled lot numbers were provided for each infant. Measurements and main results: After solid foods were added, daily human milk intake declined at a rate of 77 gm/mo ( p Conclusions: Energy intake of human milk-fed infants did not increase after solid foods were added to their diet but was maintained at approximately 20% below recommended levels. Energy intake appeared to reflect infant demands. These data suggest that the recommendations for the energy requirements of infancy should be reevaluated. The growth pattern of exclusively breast-fed infants differs from that of the National Center for Health Statistics reference population. These observations raise questions about the adaptive response of human milk-fed infants to different levels of energy intake and about the estimations of energy requirements based on the sum of basal metabolism, activity, growth, and diet-induced thermogenesis.