Prenatal exposure to the smell of vegetables shapes toddlers’ food preferences, researchers have found, with children as old as three retaining a lasting memory of flavours encountered in the womb.
Toddlers retain memory of flavours from the womb
The latest findings, published in the journal Developmental Psychobiology, built on a long-running study led by Durham University. Researchers followed up on 12 three-year-olds whose mothers had participated in earlier stages of the research during pregnancy. The mothers had consumed daily capsules containing either carrot or kale powder for three consecutive weeks until giving birth – a method chosen partly because drinking large amounts of vegetable juice was unpalatable for some pregnant women.
At age three, the children were presented with wet cotton swabs infused with either carrot or kale powder and filmed as they smelled them; they did not taste the powders. Their facial reactions were coded using a hedonic scale and compared with observations recorded before birth and around three weeks after birth. The results showed that children whose mothers had taken carrot capsules displayed fewer negative reactions to the scent of carrots, while those whose mothers had consumed kale powder reacted more favourably to the smell of kale.
Professor Nadja Reissland, from Durham University’s department of psychology, said: “Looking at the children’s reactions aged three, you can see it’s a genuine response, they are not acting. Each time, we coded their facial expressions when exposed to either the carrot or kale flavour or smell. What we see over time is that the children are still more favourable to the vegetables they were exposed to while they were in the womb.”
How prenatal flavour exposure creates long-lasting memory
The study is the third in a series tracking the same group of children from before birth. The initial stage, published in Psychological Science in 2022, used 4D ultrasound scans to observe fetal facial expressions at 32 and 36 weeks of gestation. Fetuses exposed to carrot showed more “laughter-face” responses, while those exposed to kale – chosen for its bitter quality, which is often less preferred by infants than the sweeter taste of carrot – showed more “cry-face” responses. This provided the first direct evidence that fetuses react to flavours consumed by the mother.
A follow-up study, published in Appetite, observed the same babies around three weeks after birth. Newborns were exposed to cotton swabs infused with carrot or kale powder (or water as a control). Babies showed an increase in “laughter-face” responses and a decrease in “cry-face” responses to the smells they had experienced in the womb, indicating that they reacted more favourably to those odours. Now, the latest research demonstrates that this preference persists at least until the age of three.
The mechanism underlying this lasting memory involves the amniotic fluid. Researchers believe that fetuses experience flavours through inhaling and swallowing amniotic fluid, which carries aromas from the mother’s diet. Repeated exposure during late pregnancy – the period studied – appears to imprint the flavour in a way that influences responses years later. “From this, we can suggest that being exposed to a particular flavour in late pregnancy can result in long-lasting flavour or odour memory in children, potentially shaping their food preferences years after birth,” Professor Reissland said.
This process offers an alternative to traditional methods of encouraging vegetable consumption, such as bribery or hiding vegetables in meals. Instead, the research indicates that the foundation for food preferences is laid long before weaning begins. Dr Beyza Ustun-Elayan, a co-author from Cambridge University and Radboud University Medical Centre, whose doctoral research at Durham University focused on prenatal flavour exposure, said: “These findings open up new ways of thinking about early dietary interventions, suggesting that flavours from the maternal diet during pregnancy may quietly shape children’s responses to foods years later.”
Implications for early dietary interventions
The findings have broader implications for public health and maternal nutrition. Professor Reissland recommended that mothers-to-be maintain a rich, varied diet incorporating fruits and vegetables of diverse colours, noting that a potential consequence could be “that you have a healthier population.” The research suggests that exposing fetuses to vegetable flavours during pregnancy could encourage babies to react more positively towards these foods, potentially reducing “food-fussiness” during weaning.
The study involved collaboration between multiple institutions, including Durham University, Aston University (which provided funding for the research), the Centre national de la recherche scientifique and the University of Burgundy in France, and Radboud University Medical Centre in the Netherlands. The researchers acknowledged the small sample size – just 12 three-year-olds from the larger cohort – and the need for larger studies to confirm the findings. Professor Reissland also noted that more research is needed on other odours and their effects on the fetus and child, mentioning artificial sweeteners as an example.
While the studies show altered reactions to smells, further research is required to determine whether this translates into meaningful changes in actual vegetable consumption. Nevertheless, the pattern of facial expressions observed across gestation, infancy and toddlerhood provides strong evidence that flavour memories formed in the womb can persist for years, quietly guiding how children respond to the foods placed in front of them.