Fetuses change facial expression based on food taste, study suggests

While it is known that some children are not big fans of vegetables, a new study suggests that these food preferences may arise even before they are born.

Fetuses can make a sort of “laughing face” in utero when exposed to the taste of carrots consumed by their mother and give a “cry face” response when exposed to kale, according to a study. study published in the journal Psychological Sciencereleased this Wednesday (21).

“We decided to do this study to understand more about fetal abilities to taste and smell in the womb,” Beyza Ustun, a postgraduate researcher at the Fetal and Neonatal Research Laboratory at the University of Durham, UK, told CNN this Thursday.

While some studies have suggested that babies can taste and smell in the womb using postpartum outcomes, “our research is the first that shows direct evidence of fetal reactions to flavors in the womb,” Ustun added.

The findings show that fetuses, in the last three months of pregnancy, are mature enough to distinguish different flavors transferred from the maternal diet.

The study looked at the healthy fetuses of 100 women aged between 18 and 40 who were between 32 and 36 weeks pregnant in the north east of England.

From this, 35 women were placed in an experimental group that consumed an organic cabbage capsule, 35 were placed in a group that took a carrot capsule, and 30 were placed in a control group that was not exposed to any of the flavors.

Participants were asked not to consume any flavored foods or drinks one hour before their exams. The mothers also did not eat or drink anything containing carrots or kale on the day of their exams to make sure it would not influence the results.

While the taste of carrots might be described as “sweet” by adults, kale was chosen because it imparts more bitterness to babies than other green vegetables like spinach, broccoli or asparagus, according to the study.

After a 20-minute waiting period after consumption, the women underwent 4D ultrasounds, which were compared to 2D images of the fetuses.

The pull of the corner of the lips, suggestive of smiling or laughing, was significantly higher in the carrot group compared to the kale and control group.

While movements such as lifting the upper lip, lowering the lower lip, pressing the lips and a combination of these – suggestive of a crying face – were much more common in the kale group than in the other groups.

“By now, we all know the importance of healthy eating for children. There are many healthy vegetables, unfortunately with a bitter taste, that are generally not attractive to children,” Ustun said. She added that the study suggests that “we can change their preferences for these foods even before they are born by manipulating” a mother’s diet during pregnancy.

“We know that having a healthy diet during pregnancy is essential for the health of children. And our evidence may be helpful in understanding that adjusting the maternal diet can promote healthy eating habits for children,” she added.

Enhanced imaging technology

Advances in technology have allowed better images of the faces of fetuses in the womb, according to Professor Nadja Reissland, head of the Fetal and Neonatal Research Laboratory at the University of Durham. Reissland, who oversaw the research, developed the Fetal Observable Movement System (FMOS), with which 4D ultrasound scans were encoded.

“As technology gets more advanced, ultrasound images get better and more accurate,” she told CNN adding that this “allows us to encode fetal facial movements frame by frame in detail and over time.”

The researchers have now begun a follow-up study with the same babies after birth to see if the flavors they experienced in the womb affect their acceptance of different foods during childhood, according to the release.

All the women who participated in the study were white and British.

“More research needs to be done with pregnant women from different cultural backgrounds,” Ustun told CNN . “For example, I come from Turkey and in my culture we love to eat bitter foods. It would be very interesting to see how Turkish babies would react to the bitter taste.”

She added that “genetic differences in terms of taste sensitivity (being a super taster or not a taster) may have an effect on fetal reactions to bitter and non-bitter tastes.”