The growing importance of our gut microbiota to overall health has become increasingly evident in recent years, with more studies highlighting its significant role.

Research has shown that our gut microbiota can influence a wide range of health aspects, from how we react to fear and stress to our weight, mental well-being, and even our vulnerability to autoimmune conditions such as type 1 diabetes and lupus.

A recent study published in The Journal of Immunology explored the connection between gut microbiota and the neurodevelopmental disorder autism, using animal models. The researchers suggest that a mother’s microbiota may play a more significant role in the likelihood of developing autism than the child’s own microbiota.

John Lukens, lead researcher and PhD student from the University of Virginia School of Medicine, explained in a statement: “The microbiome can shape the developing brain in multiple ways.”

“It plays a crucial role in calibrating how the immune system of offspring responds to infections, injuries, or stress,” Lukens continued. The study suggests that a specific molecule, interleukin-17a (IL-17a), which is produced by the immune system, may be involved in this connection to autism.

IL-17a has been previously linked to diseases such as psoriasis, multiple sclerosis, and rheumatoid arthritis. It plays an important role in preventing infections, especially fungal infections, and can influence brain development while still in the womb.

To test this theory, the researchers suppressed IL-17a in lab mice. They selected female mice from two different labs for the experiment. The first group of mice had gut microbiota that made them prone to an inflammatory response triggered by IL-17a, while the second, control group did not.

When IL-17a was suppressed, the offspring of both groups exhibited normal behaviors at birth. However, when the IL-17a molecule was allowed to function normally, the pups born to mothers in the first group developed a neurological disorder resembling autism, marked by impairments in social interaction and repetitive behaviors.

To verify that this was caused by the specific microbiota of the first group, the researchers performed a fecal transplant from the first group to the second group. The goal was to alter the second group’s microbiota to match that of the first. As expected, the second group’s pups later developed the same neurological disorder resembling autism.

While these findings are based on early studies involving mice and may not directly apply to human pregnancies, they suggest a promising new direction for autism research. The results provide compelling evidence that a mother’s gut health could influence the development of neurodevelopmental disorders, at least to some degree.

Looking ahead, Lukens said the next step is to identify which aspects of the mother’s microbiome are linked to autism development and to explore whether similar correlations can be found in humans.

“There are many more molecules to investigate,” Lukens added. “IL-17a may just be one piece of a much larger puzzle.”