Leaky gut, also known as increased intestinal permeability, is a digestive disorder that develops when tight junctions loosen or become damaged, allowing undigested food, bacteria, or toxins to leak through the wall of the intestine. Therefore, a leaky gut can worsen the symptoms of autism and can cause problems with brain function.
https://www.autismparentingmagazine.com/leaky-gut-autism-symptoms/