Does protein intake during pregnancy affect infants' facial features?

A new study, published in Nature Communications, revealed a novel link between the child's face and pregnancy lifestyle, specifically protein intake during pregnancy.

A child is expected to share facial features with their parents. However, the face is also influenced by factors beyond genetics, so-called environmental factors. Among those, lifestyle during pregnancy is an essential factor. For example, extensive alcohol consumption during pregnancy can lead to facial abnormalities in the child.

A research team led by Andrei Chagin, Professor of Molecular Medicine, the University of Gothenburg, delved into the mechanisms that control the formation of the facial bone structure during the embryonic phase. The studies revealed that a particular signalling pathway in the cells seemed to play a crucial role in shaping the face.

In the study, researchers performed a genome-wide analysis of RNA transcription from non-coding regulatory elements by sequencing the facial mesenchyme of human embryos and cross-checking the active enhancers thus identified against genes, by GWAS for the normal range human facial appearance. To assess the functional role of the pathways involved, they manipulated both genetically and pharmacologically in mice and zebrafish.Pregnant mice were given diets with high and low protein levels.

The results revealed the signaling pathway, known as mTOR which controls several cell functions, including cell division and cell survival. The researchers found that the mTOR pathway modulates the formation of facial skeletal structures in humans, mice, and zebrafish.The protein levels in the female's diet were consistent with the activity level of mTOR in the developing face. In newborn offspring, the differences in the face were noticeable, although subtle.

“It is difficult to describe the exact effects, which can be caused by protein content in the diet during human pregnancy. But our data suggest that the mechanism is evolutionarily conserved and, from this perspective, likely serves to increase variability in the feeding apparatus, thus, allowing animals to adapt to various feeding sources in the wild. In mice, we see, for example, an enlarged nasal cavity in the offspring of mice fed a protein-enriched diet and a slightly elongated jaw in mice where the mother has eaten a low-protein diet,” said Andrei Chagin.

Reference:Xie, M., et al. (2024). The level of protein in the maternal murine diet modulates the facial appearance of the offspring via mTORC1 signaling. Nature Communications. doi.org/10.1038/s41467-024-46030-3.