Babies taste, react to different food consumed by their mothers, study finds

In their findings, published in the journal Psychological Science on September 21, the team found that while foetuses exposed to carrot flavour displayed a “laughter-face” expression, those exposed to kale consumed by their mothers showed more of a “cry-face” response.

The study

The study examined the foetuses of 100 British women, aged between 18-40, who were 32-36 weeks pregnant.

Two experimental groups were created, with 35 women in each of them. In the first, the mothers were given a capsule containing 400 mg of carrot powder, and in the second the participants consumed capsules containing 400 mg of kale powder. Carrot was chosen because its flavour is described as sweet by adults, while kale contains a more bitter flavour profile, the study said. Another 30 mothers were placed in a control group and were not exposed to any flavour.

All participants were asked not to eat or drink anything one hour before their scan, while mothers in the experimental groups were asked to avoid consuming anything containing carrot or kale on the day of their scans.

After waiting for 20 minutes, the team took 4D ultrasound scans of the mothers for about 25 minutes. They then examined the facial expressions and movements of the foetuses, by analysing each frame of the ultrasound footage.

The results

The team found that after the mothers consumed a carrot capsule, the foetuses were more likely to display “laughter face” reactions, which include facial movements like lip-pulling, compared to those that consumed kale or no capsules. On the other hand, among the mothers that consumed a kale capsule, the foetuses were more likely to show “cry face” reactions, like upper-lip raises, lower-lip depressor and nasolabial furrowing.

The facial reactions of foetuses in both the sweet and bitter flavour groups, compared to those in a control group who were not exposed to either flavours, showed that ingestion of even a small amount of powdered carrot or kale (400 mg) was sufficient to stimulate a reaction.

Additionally, both the “laughter face” and the “cry face” reactions occurred only 30 minutes after the mothers ingested the capsules. “Thus, in this short time, the flavour content of the capsules undergoes digestion, absorption into the mothers’ bloodstream, metabolisation and circulation through the placenta and foetus, collection in the amniotic fluid, and fetal chemoreceptors,” the study found.

The significance

While other studies based on post-birth outcomes have shown that babies can taste and smell in the womb, the team claims that this is the first to see their reactions before birth.

The researchers claim that food consumed by pregnant women can have a long-term impact on a child’s food preferences and improve their eating habits later in life.

“We think that this repeated exposure to flavours before birth could help to establish food preferences post-birth, which could be important when thinking about messaging around healthy eating and the potential for avoiding ‘food-fussiness’ when weaning”, said lead researcher Beyza Ustun, a postgraduate researcher in the Fetal and Neonatal Research Lab, Department of Psychology, Durham University,

Co-author Professor Nadja Reissland, head of the Fetal and Neonatal Research Lab, Department of Psychology, Durham University, told The Indian Express “What we could demonstrate in the fetus is that they distinguish between different tastes which they experience in their womb environment. These taste experiences in the amniotic fluid derive from the mother’s diet. The fetus is “enculturated” or “prepared” for the food environment they will encounter when being weaned. This is also transferred through breastfeeding of course.”

She also said that her team is currently investigating how babies react when exposed to tastants (chemicals that produce taste sensations) in the womb. They expect that tastes experienced prenatally will transfer and lead to its acceptance postnatally. This, Professor Reissland added, “is indicated by other research which found that when mothers ate certain flavours babies were attracted to these flavours after birth.”