Brief Summary

Flavor is the primary dimension by which young children determine food acceptance. However, children are not merely miniature adults since sensory systems mature postnatally and their responses to certain tastes differ markedly from adults. Moreover, emerging research has revealed that there are sensitive periods during infancy such that early flavor experiences serve to modify later responses to flavors and foods. The proposed study aims to investigate this important issue by using as a model system a class of infant formulas which are hydrolyzed protein based and thus have very pronounced and distinctive flavors which are unpalatable to older-aged infants and adults. This research was initiated because of anecdotal reports by pediatricians that although it is easy to introduce this type of formula to infants during the first months of life, it becomes extremely difficult to do so later in infancy. Indeed, recent studies in the investigators' laboratory provided the first experimental demonstration that infants younger than 4 months of age willingly accept substantial amounts of, and satiate while feeding, a novel, protein hydrolysate formula. In marked contrast, infants older than 4 months reject the protein hydrolysate formula and this rejection occurs within the first minute of a feed, a finding that strongly suggests the sensory qualities of the formula are responsible, at least in part, for this rejection. Moreover, this rejection is not evident when the investigators test older-aged infants with other unfamiliar, but non-hydrolysate, formulas. In other words, the rejection appears to be in response to a particular component or components of protein hydrolysate formulas. This shift in acceptability can be ameliorated by prior exposure. That is, if these formulas are introduced to infants within the first few months of life and are fed continuously, they remain highly acceptable throughout infancy and early childhood. These observations implicate a sensitive period during development, occurring somewhere before 4 months of age, during which exposure to a formula, which is unpalatable to adults and infants over 4 months of age without exposure, renders it acceptable and presumably palatable. To the investigators' knowledge, this is the clearest example of a sensitive period in the development of responses to foods and flavors in humans thus far identified. There is a paucity of information on whether and how the composition of formulas fed to infants influences their short-term feeding behaviors during the first few months of life. The primary objective of this longitudinal study is to determine the period during early infancy when exposure to the casein-hydrolysate formula, Nutramigen, renders it acceptable during later infancy. The study also aims to determine how early sensory experiences with formula impact upon food acceptance during infancy (8-9 months of age) and childhood. The investigators will also explore how variation in the genes that encode for taste receptors influence preferences for foods and other behaviors.

Trial Health

On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment

participants targeted

Target at P75+ for not_applicable healthy

Timeline

Completed

Started Nov 2006

Longer than P75 for not_applicable healthy

Geographic Reach

1 country

1 active site

Status

completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

3.6 years study duration

Study Start

First participant enrolled

November 1, 2006

Completed

2.9 years until next milestone

First Submitted

Initial submission to the registry

October 12, 2009

Completed

2 days until next milestone

First Posted

Study publicly available on registry

October 14, 2009

Completed

7 months until next milestone

Primary Completion

Last participant's last visit for primary outcome

May 1, 2010

Completed

1 month until next milestone

Study Completion

Last participant's last visit for all outcomes

June 1, 2010

Completed

Last Updated

October 3, 2012

Status Verified

October 1, 2012

Enrollment Period

3.5 years

First QC Date

October 12, 2009

Last Update Submit

October 2, 2012

Conditions

Healthy

Keywords

infancynutritionprotein hydrolysate formulaflavor preferencesfood preferencesgrowthemotional developmentmother-infant interactioninfant temperamentfeeding patterningtaste receptor and obesity genotypesensitive period

Outcome Measures

Primary Outcomes (1)

infants' intake, length of feeding and patterning of feeding of Nutramigen relative to Enfamil (infant-led feeding condition)
0.5-8.5 months

Secondary Outcomes (6)

infant growth (weight and length)
0.5 to 8.5 months of life
maternal perceptions of infant enjoyment of feeding
8.5 months
infants' exploration of toys as a function of scent
9 months
infants' intake of foods as a function of flavor and chemical composition
8 months and 2-3 years
infants' temperament and behavioral development
0.5 months -2years
+1 more secondary outcomes

Study Arms (6)

Group EEEEEEE

ACTIVE COMPARATOR

Infant is fed Enfamil from 0.5-7.5 months of life

Other: Enfamil, milk-based formula

Group ENEEEEE

EXPERIMENTAL

Infant is fed Enfamil during 0.5-1.5 months of life, Nutramigen from 1.5-2.5 months of life and then Enfamil 2.5-7.5 of life.