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Ingestive responses of human newborns to salty, sour, and bitter stimuli
Insights
Newborns show taste preferences, avoiding citric acid in sucrose solutions. They maximally inhibit water intake, indicating strong innate controls on ingestion behaviors in early life.
Area of Science:
- Human infant feeding behaviors
- Sensory perception in newborns
- Early life taste responses
Background:
- Human newborns exhibit complex feeding behaviors.
- Understanding early taste perception is crucial for infant development and nutrition.
- Previous studies indicated limited responses to weak taste solutions in neonates.
Purpose of the Study:
- To investigate the taste preferences of human newborns.
- To determine if newborns can differentiate between various taste stimuli.
- To assess the role of taste in regulating fluid intake in neonates.
Main Methods:
- Newborns (1-4 days old) were presented with two fluids differing in taste for 3-minute intervals.
- Ingested volumes were precisely measured to quantify intake.
- Sucrose solutions were used as a baseline, with additions of urea, citric acid, or sodium chloride to assess differential responses.
Main Results:
- Newborns did not differentially ingest water versus bitter or sour solutions.
- Addition of citric acid to a sucrose solution significantly decreased intake compared to plain sucrose.
- Infants showed indifference to the addition of urea or sodium chloride in sucrose solutions.
Conclusions:
- Newborns appear to maximally inhibit water ingestion, suggesting strong regulatory mechanisms.
- Taste, particularly sourness (citric acid), plays a significant role in modulating fluid intake in human neonates.
- These findings highlight the sophisticated sensory capabilities and regulatory processes present at birth.
Abstract:
Human newborns (1-4 days old) were offered two fluids differing in taste for 3 min each. The volumes ingested were measured. Infants offered water and bitter or sour solutions did not ingest them differentially, which corroborated earlier observations with weaker solutions. A sucrose solution was used to raise baseline ingestion above that of water. Infants offered the sucrose solution with and without urea, citric acid, or sodium chloride consumed less of it when citric acid was added. They were indiffferent to the addition of urea or sodium chloride. The failure to observe intakes lower than that of water suggests that newborns maximally inhibit their ingestion of water. The effects of sex, age, birth weight, and individual consistency on intake were assessed.