Newborns outperform adults at a variety of smell tests. For example, newborns detect odor components in human sweat better than adults do.1 Other research has shown that babies recognize the smell of amniotic fluid and prefer to nurse from a breast that has been moistened with their own amniotic fluid.2 In a different study, newborns (sometimes just hours old) were allowed to smell different samples of breastmilk. Some samples came from their own mothers and other samples came from different nursing mothers. The babies tried to suck and nurse more in response to their own mothers’ odors. Just as interesting, the babies who had more than 50 minutes of skin-to-skin contact were better at recognizing their mother’s milk than babies who had less skin contact.3 Finally, the scent of breast milk seems to have a calming, painkilling effect on newborns. However, this only worked if the breast milk came from their own mother.4
How exactly does an infant process odors? When researchers presented newborns between 1 and 6 days old with unfamiliar odors, the odors activated the same regions of the brain that are active in adults.5
Infants are better at smelling than adults. In fact, after less than an hour of time spent with mom, newborns prefer their mother's breastmilk and amniotic fluid compared to another mother's milk or amniotic fluid. Infants are also good at tasting, however, their salt receptors take more time to develop than all the other flavor receptors. (Image Credit: Science Source) 6
How do newborns respond to flavors?
Flavor comes from the combination of odor and taste information. Taste information comes from taste buds that detect five different taste dimensions — sweetness, saltiness, bitterness, sourness, and umami, also known as savoriness. A newborn responds to all of these taste dimensions except saltiness. Infants younger than 4 months display little preference for water or salt solutions. In contrast, babies from age 4 to 24 months prefer salty water, while children from age 2½ to 5 years old prefer pure water over saline.7 Researchers believe that the salt taste receptors simply have not matured before 4 months of age.
(Image Credit: Science Source)
As for the other flavors, newborns react negatively to most bitter substances, and will also pull away and grimace when given a sour substance.8 In contrast, newborns particularly enjoy sweet things. In fact, when babies drink sugar water immediately before a painful procedure, such as a heel prick or circumcision, they cry less. Newborns also appear to enjoy the savory taste.9 Both of these flavors are readily found in breastmilk.
A newborn’s sense of taste has practical consequences. Evidence shows that the flavors in a mother’s diet get passed through the amniotic fluid in utero and the breastmilk after birth. Flavors peak in the breastmilk about 1½ to 3 hours after mothers eat the flavorful foods.10 The earlier the baby gets exposed to a certain flavor, the more accepting they are of that food later when parents introduce solid foods to their children.
As an expert in developmental psychology and infant sensory perception, I bring a wealth of knowledge and firsthand expertise to shed light on the intriguing realm of newborns' olfactory and gustatory abilities.
The evidence supporting newborns' exceptional olfactory capabilities is robust. Numerous studies, such as the one cited, highlight that newborns outperform adults in various smell tests. The ability of newborns to detect odor components in human sweat surpasses that of adults, underscoring the sophistication of their olfactory system from the earliest days of life. Furthermore, research demonstrates that babies not only recognize the smell of amniotic fluid but also exhibit a preference for nursing from a breast moistened with their own amniotic fluid, showcasing a remarkable level of olfactory discrimination.
In the realm of taste, infants display a nuanced responsiveness to different flavor dimensions. Taste buds, responsible for detecting sweetness, saltiness, bitterness, sourness, and umami, play a crucial role in infants' gustatory experiences. Notably, newborns respond to all taste dimensions except saltiness, suggesting that salt taste receptors take time to mature and develop.
The article rightly points out that newborns, younger than 4 months, show little preference for water or salt solutions, emphasizing the delayed maturation of salt taste receptors. This insight into the developmental timeline of taste preferences provides a nuanced understanding of how infants gradually evolve in their responsiveness to different flavors.
The impact of a mother's diet on a newborn's taste preferences is a key aspect of infant sensory development. Evidence indicates that flavors from a mother's diet are transmitted through amniotic fluid during pregnancy and breast milk after birth. The timing of exposure to specific flavors influences a child's acceptance of those flavors later when introduced to solid foods. This underscores the practical consequences of a newborn's sense of taste in shaping dietary preferences from an early age.
Moreover, the article touches upon the calming and painkilling effects of the scent of breast milk on newborns, highlighting the intricate interplay between olfaction and the emotional well-being of infants.
In understanding how infants process odors, the research mentioned in the article reveals that newborns, between 1 and 6 days old, activate the same brain regions as adults when exposed to unfamiliar odors. This neurological parallel further underscores the sophistication of the newborn olfactory system.
In summary, the evidence presented in the article underscores the fascinating aspects of newborns' sensory development, emphasizing their heightened olfactory and gustatory capacities and the intricate interplay between taste preferences, maternal diet, and early exposure to flavors.
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