Excretion of Fat by Normal Full-Term Infants Fed Various Milks and Formulas

Abstract

Although nitrogen, calcium, and phosphorus balance studies with normal full-term infants have been reported from our Infant Metabolic Unit, data on excretions of fat by infants between 8 and 180 days of age have been mentioned only briefly in a few of the publications. The present report concerns excretions of fat during 364 3-day metabolic balance studies with 50 infants fed the following milks or formulas ad libitum: processed human milk, homogenized, or evaporated cow’s milk, or commercially available or experimental formulas containing butterfat or vegetable oils. Intakes of fat were in many instances greater than those reported previously by other investigators, a circumstance probably explained by the greater volumes of milk or formula consumed during ad libitum than during restricted feeding and by the relatively high fat content of a number of the milks and formulas. Excretions of fat were unexplainably high by infants receiving an experimental soy isolate-based formula with fat provided as a mixture of corn and coconut oils. Otherwise, with few exceptions, excretions of fat by infants fed human milk or formulas with fat supplied as vegetable oils were less than 1 g/kg per day. Excretions of fat by infants fed homogenized cow’s milk were in many instances greater than 2 g/kg per day and rarely less than 1 g/kg per day, whereas infants fed evaporated milk without added carbohydrate or a formula with butterfat generally excreted between 1 and 2 g/kg per day. It is suggested that a diagnosis of fat malabsorption in infancy may be established by demonstrating excretions of fat greater than 2 g/kg per day during ad libitum feeding of diets that offer no more than 40% of calories from butterfat or no more than 50% of calories from vegetable oils. It seems inadvisable to feed homogenized milk without added carbohydrate during the early months of life.