The crucial role of gut microbiota in our overall health is gaining growing attention, with research now linking it to everything from emotional responses and weight to autoimmune conditions like type 1 diabetes and lupus. But new findings suggest its influence may reach even further—into the development of the brain itself.
A groundbreaking animal study published in The Journal of Immunology reveals a surprising connection between gut bacteria and autism. According to the researchers, the gut microbiome may play a key role in the risk of developing autism—but not necessarily your own microbiome. Instead, the microbiota of your mother could hold the most influence.
“The microbiome can shape the developing brain in multiple ways,” explained lead researcher John Lukens, PhD, from the University of Virginia School of Medicine. “It’s crucial in calibrating how the immune system of the offspring responds to infection, injury, or stress.”
These findings add to a growing body of evidence that our gut bacteria—especially those passed from mother to child—may be more deeply entwined with neurodevelopment than previously understood.
A new study offers fascinating insight into how a mother’s gut health during pregnancy might influence her child’s risk of developing autism—and it all centers around a powerful immune molecule known as interleukin-17a (IL-17a).
Already linked to inflammatory diseases like psoriasis, multiple sclerosis, and rheumatoid arthritis, IL-17a plays a critical role in the immune system, particularly in defending against fungal infections. But researchers have now found it may also affect brain development in the womb, potentially contributing to autism-like behaviors.
To investigate, scientists at the University of Virginia used two groups of female lab mice with distinct gut microbiota. One group had microbes that triggered an inflammatory immune response involving IL-17a, while the other group (the control group) did not.
When IL-17a activity was artificially suppressed in both groups, their offspring displayed typical neurological development at birth. However, when left untreated, the pups born to the first group—those with inflammation-prone gut bacteria—developed behaviors resembling autism, such as social difficulties and repetitive actions.
To confirm the gut microbiota’s role, the team performed a fecal transplant, introducing bacteria from the first group into the control mice. As expected, their offspring also developed autism-like symptoms, strengthening the evidence that the maternal microbiome, not just genetics, may influence neurodevelopmental outcomes.
While these findings are still early and based on animal models, they open a promising new avenue in autism research. “There’s clearly a connection between the maternal microbiome, the immune system, and brain development,” said lead author Dr. John Lukens.
The next step, Lukens explained, is to identify which microbes or microbial signals in the maternal gut are associated with these changes and determine whether similar patterns can be found in human pregnancies.
“There are many molecules to study,” he added. “IL-17a may be just one piece of a much larger puzzle.”