Sensitive Periods in Early Flavor Learning

This is a basic research, longitudinal and experimental study in which infants will be randomized into one of six groups (N=10-15 per group) differing in the timing and type of formula that the infant will be fed during each month of the 7-month exposure period. Each mother-infant dyad will be studied from the 2-3rd week of life until approximately 9 months of age. When the infant is less than three weeks of age and the mother's decision to formula feed is well established, infants will be randomized into one of six groups differing in the timing and type of formula that the infant will be fed during each month of the 7-month exposure period. One group (Control EEEEEEE) will be assigned to a milk-based formula, Enfamil (E), whereas another group (NNNNNNN) will be assigned to Nutramigen (N) during the entire 7-month period of this study. The other 4 groups will be assigned to feed Nutramigen for specified periods during their first seven months of life (Groups ENEEEEE, EEENEEE, ENNNEEE). A variety of methodologies developed in our laboratory will be employed to capture the infants' responses to a particular flavor or taste after the exposure period. That is, at the end of the exposure period, infants will be videotaped while they are 1) feeding formulas; 2) feeding foods (e.g., cereal; soups) that differ in flavors; and 3) exploring scented toys. Each month, infants will be weighed and measured for length as well as evaluated for cognitive and motor development and mothers will completed standardized questionnaires regarding infant temperament. A cheek swab from the mothers and infants will be obtained and genotyped for taste receptor and taste- and obesity- related genes.