Sensitive Periods in Early Flavor Learning

October 2, 2012 updated by: Julie A. Mennella, Monell Chemical Senses Center

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.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Actual)

79

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Pennsylvania
      • Philadelphia, Pennsylvania, United States, 19104
        • Monell Chemical Senses Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

2 weeks to 4 weeks (CHILD)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy, term infants of any racial background
  • Infants may be of either sex
  • Infants must be 2 weeks of age
  • Infants must be exclusively feeding a cow's milk-based formula
  • Mothers must be over 18 years of age

Exclusion Criteria:

  • Infants who were preterm
  • Infants who have medical conditions that interfere with feeding or eating
  • No major complications during pregnancy or at birth

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: BASIC_SCIENCE
  • Allocation: RANDOMIZED
  • Interventional Model: PARALLEL
  • Masking: DOUBLE

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
ACTIVE_COMPARATOR: Group EEEEEEE
Infant is fed Enfamil from 0.5-7.5 months of life
Other: Enfamil, milk-based formula
Enfamil, milk-based formula, fed as formula source during first 8.5 months of life
EXPERIMENTAL: Group ENEEEEE
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.
Other: Nutramigen (Flavor and Type of Infant Formula)
Nutramigen, protein hydrolysate formula, fed to infants as sole formula source during specified times during the first 8.5 months of life
EXPERIMENTAL: Group EENEEEE
Infant is fed Enfamil 0.5-2.5 months of life, Nutramigen from 2.5-3.5 months of life and then Enfamil from 3.5 to 7.5 months of life
Other: Nutramigen (Flavor and Type of Infant Formula)
Nutramigen, protein hydrolysate formula, fed to infants as sole formula source during specified times during the first 8.5 months of life
EXPERIMENTAL: Group EEENEEE
Infant is fed Enfamil from 0.5-3.5 months of life, Nutramigen from 3.5-4.5 months of life and then Enfamil from 4.5-7.5 months of life.
Other: Nutramigen (Flavor and Type of Infant Formula)
Nutramigen, protein hydrolysate formula, fed to infants as sole formula source during specified times during the first 8.5 months of life
EXPERIMENTAL: Group ENNNEEE
Infant if fed Enfamil from month 0.5-1.5 months of life, Nutramigen from 1.5 to 3.5 months of life and then Enfamil again 3.5-7.5 months of life.
Other: Nutramigen (Flavor and Type of Infant Formula)
Nutramigen, protein hydrolysate formula, fed to infants as sole formula source during specified times during the first 8.5 months of life
EXPERIMENTAL: Group NNNNNNN
Infant is fed Nutramigen from 0.5-7.5 months of life.
Other: Nutramigen (Flavor and Type of Infant Formula)
Nutramigen, protein hydrolysate formula, fed to infants as sole formula source during specified times during the first 8.5 months of life

What is the study measuring?

Primary Outcome Measures

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

Secondary Outcome Measures

Outcome Measure
Time Frame
infant growth (weight and length)
Time Frame: 0.5 to 8.5 months of life
0.5 to 8.5 months of life
maternal perceptions of infant enjoyment of feeding
Time Frame: 8.5 months
8.5 months
infants' exploration of toys as a function of scent
Time Frame: 9 months
9 months
infants' intake of foods as a function of flavor and chemical composition
Time Frame: 8 months and 2-3 years
8 months and 2-3 years
infants' temperament and behavioral development
Time Frame: 0.5 months -2years
0.5 months -2years
taste receptor and obesity genotypes.
Time Frame: 8 months and 2-3 years
8 months and 2-3 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Monell Chemical Senses Center

Collaborators

National Institutes of Health (NIH)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

November 1, 2006

Primary Completion (ACTUAL)

May 1, 2010

Study Completion (ACTUAL)

June 1, 2010

Study Registration Dates

First Submitted

October 12, 2009

First Submitted That Met QC Criteria

October 13, 2009

First Posted (ESTIMATE)

October 14, 2009

Study Record Updates

Last Update Posted (ESTIMATE)

October 3, 2012

Last Update Submitted That Met QC Criteria

October 2, 2012

Last Verified

October 1, 2012

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 803712

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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