Gut microbiome is linked to autism. Eating probiotic l.reuterinmay may help. L.reuteri does this by upregulating host oxytocin levels which rewards social behavior.
I thought that relationship was no longer believed. It's just that autistic people may eat differently causing gut biome to be different. (Sorry I don't have time to source it.)
https://pubmed.ncbi.nlm.nih.gov/27825953/