Children can "remember" the smell of vegetables even before birth: a study tracked the reaction from the fetus up to 3 years old.

A new study in Developmental Psychobiology shows that three-year-old children responded less negatively to the smells of vegetables they had already encountered before birth through their mothers' diets. This involved two tastes and smells: carrot, a milder, less bitter stimulus, and kale, a more bitter stimulus.

This study continues earlier observations by the same research group. Initially, the children's responses were recorded before birth using ultrasound at 32 and 36 weeks of pregnancy, then at approximately three weeks postnatally, and now at age three. This design makes the study particularly interesting: it attempts to trace the same sensory response through several stages of development.

Twelve children participated in the final stage. The researchers held a damp cotton swab dipped in carrot or kale powder to the children's noses, recorded their reactions on video, and then coded their facial expressions as more positive or more negative. Importantly, the children did not taste the vegetables; their response to the smell was assessed.

The authors' main conclusion: repeated exposure to a particular taste or smell in late pregnancy can form long-term chemosensory memory that persists at least until early childhood. This doesn't mean the baby is guaranteed to eat vegetables without resistance, but it does indicate that familiarity with food aromas may begin even before birth.

Parameter	What is known
Magazine	Developmental Psychobiology
Article Title	Do Human Fetuses Form Long-Lasting Chemosensory Memories?
Main theme	Long-term memory of tastes and smells acquired before birth
Stimuli studied	Carrots and kale
Age of last observation	3 years
Number of children in the last stage	12
DOI	10.1002/dev.70165

How the study was conducted

In the original controlled experiment, pregnant women took capsules containing carrot or kale powder. This format was chosen deliberately: according to the researchers, trying to use vegetable juices proved inconvenient for some participants, so capsules became a more practical way to standardize the flavor effects.

During pregnancy, fetal reactions were assessed using ultrasound scans at 32 and 36 weeks. The researchers coded facial expressions after exposure to the corresponding taste: relatively positive reactions were described as "laughter faces," while more negative reactions were described as "cry faces."

After birth, the same logic was used until the infants were approximately three weeks old. Then, when the children turned three, the researchers tested their reactions again, this time to the smell of carrots and kale, rather than to taste. Cotton swabs containing the vegetable powder were held to the nose, and their facial expressions were videotaped and analyzed.

This approach didn't measure how many vegetables a child would actually eat at lunch. It measured early emotional and sensory responses to odors: less disgust, more neutrality, or more positive facial expressions. Therefore, the study is best understood as a study of early sensory memory rather than as proof of a proven method for cultivating eating habits.

Stage	What did they do?
Pregnancy	Mothers took capsules containing carrot or kale powder
32 and 36 weeks	Fetal responses were assessed using ultrasound.
About 3 weeks after birth	The infants' reactions were re-tested.
3 years	Children were given the scent of carrots and kale on cotton swabs.
Main assessment	Facial expressions: more positive or more negative reactions

What exactly was discovered?

Children whose mothers took carrot powder capsules during pregnancy responded less negatively to the smell of carrots at age three. However, they were more likely to react negatively to the smell of kale, indicating that the effect was specific to the stimulus the child encountered before birth.

A similar pattern was observed in children whose mothers took capsules containing kale powder. These children reacted less negatively to the smell of kale, even though kale is typically more difficult for children to digest due to its bitter profile. Popular accounts of the study emphasize that some children in the kale group even showed positive facial expressions when exposed to the smell of the vegetable.

Professor Nadja Reissland of Durham University explains the result this way: the babies still responded more favorably to the vegetables they were familiar with in the womb. She explains that this suggests that exposure to a specific taste in late pregnancy may lead to long-term memory of a taste or smell.

Co-author Dr Beyza Ustun-Elayan from the University of Cambridge noted that such findings open up a new way of thinking about early nutritional interventions: the taste and smell of a mother's diet during pregnancy can subtly influence how a child responds to foods years later.

Prenatal exposure group	Reaction at 3 years
Carrots during pregnancy	Fewer negative reactions to carrot smell
Kayle during pregnancy	Fewer negative reactions to kale smell
An unfamiliar vegetable	The reaction could have been more negative
General conclusion	The reaction was linked to a specific smell, not just vegetables in general.

Why can a fetus sense tastes and smells at all?

During pregnancy, molecules from the mother's diet can enter the amniotic fluid. The fetus swallows and inhales amniotic fluid, gradually encountering chemical cues associated with the mother's diet. Research summary notes that flavor compounds from foods such as carrots or kale can appear in the amniotic fluid shortly after the mother consumes them.

This doesn't mean the fetus "eats" vegetables in the traditional sense. It's about chemosensory stimulation: substances associated with taste and smell reach the environment with which the fetus comes into contact. This is why researchers talk about smell as well as taste, because these sensory channels are closely intertwined in the fetus and newborn.

Kale and carrots were chosen as contrasting stimuli. Carrots have a milder, sweeter, and less bitter flavor profile, while kale is more bitter and potentially less appealing to young children. This helped test whether prenatal familiarization could reduce negative reactions even to the more challenging vegetable odor.

Dr. Benoist Schaal of the French National Centre for Scientific Research noted that the study confirms the ability of human fetuses to taste the food their mothers eat, and that this can influence their preferences years after birth. He also emphasized the need to study other odors and how they specifically affect the fetus and child.

Mechanism	A simple explanation
Mother's diet	Some flavor and aroma compounds enter the amniotic fluid
Amniotic fluid	The fruit swallows and inhales it
Sensory Introduction	The taste and smell of food can be perceived even before birth
Repeated exposure	May reduce negative reactions to familiar stimuli
Possible outcome	The child later reacts more calmly to the familiar vegetable smell

What does this mean for baby food?

For parents and nutritionists, the primary concern is obvious: if a child is exposed to vegetable aromas before birth, it may help reduce their resistance to certain vegetables later on. This is especially important for bitter vegetables, which children often reject due to an innate sensitivity to bitterness.

However, this result shouldn't be interpreted as a direct instruction to "eat kale, and your child will love it." The study didn't measure long-term actual vegetable consumption, but rather assessed facial expressions in response to the smell. There may be a connection between a less negative reaction to the smell and actual consumption of the vegetable, but this remains to be confirmed.

If future studies confirm the effect on eating behavior, this could become part of gentle preventative strategies. For example, pregnant women could be advised to eat a varied diet with vegetables not only for their own health but also as a way to introduce their child to healthy foods early on.

Such recommendations must take into account safety, tolerability, cultural differences, and actual dietary habits. Professor Reissland has already noted that the idea can be adapted to different cultures: in some countries, this might mean vegetables, while in others, it might mean fish or other healthy foods typical of the local diet.

Possible application	What you need to understand
A varied diet for pregnant women	May introduce the fetus to different food aromas
Vegetables with a bitter taste	Prenatal familiarization may reduce negative reactions
Baby food	Potential help in shaping vegetable acceptance
Cultural adaptation	Incentives should be consistent with the family's normal diet.
Limitation	It has not yet been proven that this increases actual vegetable consumption.

Why the findings should be interpreted with caution

The main limitation is the very small sample size. Only 12 children participated in the final stage, so the results cannot be considered definitive. The researchers themselves acknowledge that a much larger study is needed to verify the robustness of the effect.

The second limitation is that the study assessed facial expressions rather than actual nutrition. A child may react more calmly to the smell of a vegetable but still refuse to eat it due to its texture, appearance, temperature, mood, family atmosphere at the table, or feeding habits.

The third limitation is the possible influence of multiple factors after birth. A child's food preferences are influenced by breastfeeding, complementary feeding, frequency of vegetable offerings, parental example, pressure at the table, genetic sensitivity to bitterness, food culture, and food availability. Prenatal influences may be only one of many factors.

The fourth limitation is that the study only included two vegetable stimuli. The findings cannot be automatically generalized to broccoli, fish, spices, sweets, artificial sweeteners, or other dietary components. The authors themselves emphasize that other odors and their effects on the fetus and child need to be studied.

Limitation	Why is this important?
12 children	A larger sample is needed
Facial expressions instead of actual eating	The reaction to the smell is not equal to the amount eaten
Many factors after birth	Complementary feeding, family and food culture also shape preferences
Just carrots and kale	It cannot be generalized to all products
There is no long-term clinical conclusion	This is a study of sensory memory, not a ready-made prevention program.

Brief conclusion

A study by Reissland et al. shows that 3-year-olds can retain a more favorable response to the odors of vegetables they encountered before birth. Carrots and kale served as models for two distinct taste profiles, and the repetition of similar patterns before birth, after birth, and at 3 years supports the idea of long-term chemosensory memory.

The main point of this news isn't that a child's food preferences are completely determined during pregnancy. It's about a more subtle idea: a mother's diet may be one of the early cues that shapes the child's exposure to future tastes. If this is confirmed in large studies, prenatal exposure to healthy foods could become another tool for developing a healthy diet, but for now, these findings should be considered preliminary.

News source: Nadja Reissland et al. Do Human Fetuses Form Long-Lasting Chemosensory Memories? Longitudinal Follow-Up From Fetus to Young Child of Facial Responses to Flavor/Odor Stimuli. Developmental Psychobiology, 2026. DOI: 10.1002/dev.70165.