Monosodium glutamate (MSG), a common food additive, has been linked to harmful effects on developing embryos. This study aimed to explore how MSG affects the development of facial structures in chick embryos. The present study used 180 fertilized eggs, dividing them into two groups: one group received MSG, and the other did not (the control group). The embryos were studied at three stages of development. The study examined the shape and structure of the craniofacial area (head and face) under a microscope, and also looked at certain cells that play a key role in facial development.

The results showed that MSG caused several problems in the embryos. At the earliest stage, MSG led to issues like improper opening of the neural tube (a critical part of brain and spinal cord development) and eye deformities. By later stages, MSG caused facial bones to form incorrectly and delayed bone hardening. The study also found that MSG triggered the death of stem cells involved in facial development and slowed down their growth. This is the first study to report that high doses of MSG can cause serious facial deformities in embryos during development.