The vagus nerve is the major connector from our brain to our gut and the info flows both directions. If you have ever read "Why Zebras Don't Get Ulcers" you read about what happens in the animal kingdom when one has to flee for one's life: vomiting, loss of bowel control, urinating, etc. It lightens the load to get away and live to see another day. Stress acts likewise but at a more pernicious level. Re-regulating the vagus can help with these systems.
We here at NeurodivergentAlly have complied several links to information regarding ASD and GI issues below:
Just like ASD is a spectrum why your gut is acting up can be also. While I typically don’t hold much of what “autism parenting magazine” as truth I found great links to actual studies within this article helpful. (I typically try to get information from fellow ASD humans and scientific studies at known colleges) https://www.autismparentingmagazine.com/probiotics-and-autism/
Several articles listed here On Autism.org I have found their website truely helpful. https://www.autism.org/resources-on-the-gut-brain-connection-in-autism/
Sarah Buffie does and amazing job explaining "Hand Brain". If you ever have the opportunity to take one of her classes please do! You can reach her at (https://www.soulbirdconsulting.info/ ) https://youtu.be/sA8EFsmjbpU