The importance of infants' lipid intake in human milk research.

Human milk lipids are among the many nutrients delivered to the infant, providing >50% of the infant's calorie intake. These lipids are highly complex and variable, and bioactive, contributing to infant growth, development, and health. The lipid concentration of milk samples is often measured in human cohorts; however, few studies measure infant intake of milk. Intake is important because it considers the variability of both lipid concentration and infants' consumed volume of milk. Measurement of infants' lipid intake in exclusively breastfeeding infants requires 3 main considerations: human milk sampling protocol (ie, the collection of representative samples); measurement of the infant milk intake, because volume varies widely between infants; and appropriate analytical laboratory methods. The purpose of this review was to provide an overview of existing methodology and demonstrate the importance of measuring infants' lipid intake to understand the impact that human milk lipids have on infant outcomes.