In recent years, science has made it increasingly clear just how crucial our gut microbiome is to overall health. It doesn’t just impact digestion—it’s been tied to mental well-being, emotional responses, autoimmune conditions like lupus and type 1 diabetes, and even how we gain or lose weight.
Now, researchers may have found a possible connection between gut bacteria and autism. But here’s the twist: it might not be your own microbiome that matters—it could be your mother’s.
A new animal study published in The Journal of Immunology suggests that a mother’s gut health during pregnancy could influence whether her child develops autism spectrum-like behaviors. The research team, led by John Lukens from the University of Virginia School of Medicine, discovered that the gut microbiome plays a major role in shaping brain development—especially in the womb.
“The microbiome is really important to the calibration of how the offspring’s immune system is going to respond to an infection or injury or stress,” said Lukens.
The focus of the study was on a specific immune system molecule known as interleukin-17a (IL-17a). This molecule is already associated with inflammatory and autoimmune conditions like multiple sclerosis, psoriasis, and rheumatoid arthritis. It also plays a key role in defending against infections, especially fungal ones. Interestingly, IL-17a appears to have the power to affect brain development during pregnancy.
To test the theory, researchers worked with two groups of female mice. The first group had gut bacteria known to trigger an IL-17a inflammatory response. The second group did not.
When scientists blocked IL-17a in both sets of mice, their offspring showed normal behavior. But when the molecule wasn’t blocked, the offspring of the first group—those with the inflammation-inducing gut bacteria—developed autism-like behaviors, particularly in areas like social interaction and repetitive actions.
To further test their theory, the researchers performed a fecal transplant, transferring gut bacteria from the first group of mice to the second group. Once the second group’s gut microbiome resembled the first, their offspring began showing the same autism-like behaviors.
While these findings are preliminary and based on animal studies, they suggest that the mother’s gut microbiome may play a significant role in shaping neurodevelopment. It opens up new doors in autism research, particularly around how inflammation in early development could influence brain wiring.
The next phase, according to Lukens, will involve exploring whether similar patterns are found in humans. The team also wants to identify exactly what in the maternal microbiome may contribute to autism risk—and whether IL-17a is the main driver or just one part of a more complex biological process.
