Are Babies Capable Of Reacting To Taste and Smell In The Womb?


For the health of both the mother and the unborn child, eating a good, balanced diet is crucial. A balanced diet during pregnancy can lower the incidence of many birth abnormalities and is connected to optimal brain development and healthy birth weight. In addition, what a mother consumes while pregnant may influence her baby’s food preferences as they develop.

An infant’s sense of taste begins to form at eight weeks gestation, when the first taste buds appear, as per the European Food Information Council (EUFIC). There is a strong connection between the sensations of smell and taste. Our sense of taste enables us to determine whether something is sweet, bitter, salty, or sour, but our sense of smell aids in determining the precise flavor of food. Around weeks 9 to 11 of pregnancy, the individual cells required by your unborn child for their sense of smell begin to form.

A study led by Durham University’s Fetal and Neonatal Research found the first concrete evidence that babies react differently to various smells and tastes while in the womb by observing their facial expressions, in addition to the fact that they can smell and have already experienced the mother’s taste patterns long before they begin eating food themselves.

The Evidence

Pregnant women’s diets expose fetuses to various flavors made up of compound smell, taste, and chemesthesis sensations. So far, the consequences of prenatal taste exposure on chemosensory development in human infants have only been examined postnatally.

Hence, the study published in the journal Psychological Science presented the first concrete evidence of human fetal reactivity to tastes transmitted via maternal intake of a single-dose capsule by measuring fetal facial movements. 

One pill containing 400 mg of carrot or 400 mg of kale powder was given to 100 moms in the research 20 minutes before each scan. One hour before their scans, they were urged to refrain from eating or drinking anything with flavor.

To account for variables that might influence fetal reactions, the moms abstained from eating or drinking anything that contained kale or carrots on the day of their scans.

During 32 weeks and 36 weeks of pregnancy, 100 pregnant women between 18 and 40 had 4D ultrasound scans to observe how their unborn children reacted to flavors from their mothers’ meals. Shortly after the moms consumed the flavors, they observed how the fetuses responded to the carrot or kale flavors.

Based on the 4D ultrasounds, the researchers found that the facial reactions in both flavor groups, when compared to fetuses in a control group who were not exposed to either flavor, demonstrated that even a modest quantity of carrot or kale flavor exposure was sufficient to elicit a reaction.

Comparatively to the carrot group and a control group that was not exposed to any flavors, fetuses treated to kale displayed more “cry-face” reactions. In contrast, those exposed to carrots displayed more “laughter-face” reactions. The researchers discovered that the complexity of facial gestalt in the kale condition grew from 32 to 36 weeks, but not in the carrot condition. 

The findings of this study have significant ramifications for our understanding of how human taste and smell receptors develop, particularly concerning the nature and timing of behavioral responses to prenatal flavor exposure, fetal engagement of flavor memory, and the potential role of prenatal to postnatal continuity in perception and reactivity to the chemical environment.

The researchers’ conclusions suggest that what pregnant women consume may impact the taste preferences of their offspring after birth and may have ramifications for the development of good eating habits.

They also think their research should benefit moms as it provides information regarding the significance of flavor and a balanced diet during pregnancy.

They also emphasized the necessity for follow-up research that includes postnatal behavioral evaluations to determine how prenatal taste exposure can have short- and long-term effects on postnatal food choices.

Journal Reference

Ustun, B., Reissland, N., Covey, J., Schaal, B., & Blissett, J. (2022). Flavor sensing in utero and emerging discriminative behaviors in the human fetus. Psychological Science, 095679762211054. 

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