Not just adults, even babies dislike kale


Human foetuses develop taste buds anatomically from 8 weeks and can detect tastes from 14 weeks onwards.

Human foetuses develop taste buds anatomically from 8 weeks and can detect tastes from 14 weeks onwards.

Pregnant women all over the world are exposed to a number of myths and superstition about food. From what kind of food to avoid to meal timings, to-be mothers are bombarded with advice and suggestions from everywhere.

But do the babies have a preference for what a mother eats?

A new study published in the journal of Psychology Science by the researchers at Durham University, England, have found that babies in the womb can not only detect flavours and smells but also express their preference through ‘laughter face’ or ‘cry face’.

Ultrasound scan of cry-face gestalt of a kale-exposed foetus.

Ultrasound scan of cry-face gestalt of a kale-exposed foetus.
| Photo Credit: Psychology Science

The researchers analysed 4D ultrasound scans of 100 pregnant women who are 32 to 36 weeks along in their pregnancies from northeast England. They found that the foetuses exposed to carrot flavour showed ‘lip-corner puller’ or laughter-face’. While those exposed to kale flavour showed ‘upper-lip raiser’, ‘lower-lip depressor’ or ‘cry-face’.

A number of studies have suggested that babies can taste and smell in the womb, but they are based on post-birth outcomes while the current study is the first to see these reactions prior to birth.

Explaining the study, the lead researcher Beyza Ustun said in an email to The Hindu, “We were expecting to see different facial reactions to kale and carrot because these vegetables do not share the same flavour profile, kale is bitter, and carrot is non-bitter.”

Ultrasound scan of laughter-face gestalt of a carrot-exposed foetus.

Ultrasound scan of laughter-face gestalt of a carrot-exposed foetus.
| Photo Credit: Psychology Science

The study also sheds light on the sensory abilities of the foetuses and their ability to display facial responses to different flavours. 

“Kale was chosen because it conveys more bitterness to infants than other green vegetables such as spinach, broccoli, or asparagus. Carrot was chosen because postnatal studies showed that carrot is transferred to the amniotic fluid, and it does not share the same flavour profile as kale,” she added.

Human foetuses develop taste buds anatomically from 8 weeks and can detect tastes from 14 weeks onwards. From 24 weeks onwards, their olfactory sensory neurone are developed enough to detect smells. Foetuses can sense the flavours of food eaten by the mother by inhaling or swallowing the amniotic fluid. 

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As the foetus matures, its capacity to express more complex expressions develop. Foetuses can contort their facial muscles to display more complex facial movements as seen in this study.

The team, which included scientists from Aston University, Birmingham and National Centre for Scientific Research, France, also believe that the results of the study could shed light on the development of human taste and smell preceptors and its relation to memory and perception.

“We are now following these babies to see their reactions to the flavours they were exposed to in the womb. In this stage, we asked mothers to have carrot or kale flavour every day in the last 3 weeks of their pregnancy. After the birth of the baby, we tested their reactions to kale and carrot within the first month. The analysis is still ongoing, but preliminary analysis shows that we might see fewer ‘cry-face’ reactions to kale if foetuses were exposed to kale in the womb because they are accustomed to the kale flavour,” she added.

Ms Ustun emphasised the importance of a healthy diet for children. “There are lots of healthy vegetables, unfortunately, with a bitter taste, that is usually not appealing to children. But the evidence of this study provides that we can change their preferences to such foods before they were even born by manipulating mother’s diet during pregnancy,” she said.

Highlighting the implications of the study in the real world, she added, ”The evidence from the study can be helpful to understand that adjusting maternal diet can promote healthy eating habits for children.”

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