Recently pjoshea posted on this topic: Optimizing our gut microbiome with prebiotics (that create an optimized environment for beneficial microbes) and probiotics (the colony forming beneficial bacteria to repopulate the gut).
This particular probiotic bacterial species appears to be the best. But most probiotic products sold do not contain it. Others are probably fine. I normally take one from "Renew Life" brand called "Ultimate Flora Extra Care Probiotic". Yet I am considering doing one month only of the much more expensive "Pendulum" product (pendulumlife.com) which does feature Akkermansia m. It is marketed for Glucose control. This would be just to get Akker m. established in my gut where, hopefully, it wold thrive and persist.
For a prebiotic I take inulin, the very short chain fructose-oligosaccharide which is a soluble fiber that we do not digest (but the gut microbes do). It does not provide significant sugars to my diet. Important for me as I intermittent fast (OMAD: One Meal a Day) and eat ketogenic or at least very low carb. Chicory root also consists mostly of inulin. Note: this is not "insulin"!
The brain and hormonal effects of favorable gut microbiome are particularly interesting for us. (The gut-brain and gut- hypothalamic-pituitary axis discussed in the article.) -Paul
Article with abstract:
sciencedirect.com/science/a...
And full text PDF:
Gut bacteria making hormones
The guts of a radiation treatment machine
Radio sensitizers and Microbiome 
chronic inflammation.
Gut check , looking for real world post RP side effect testimonials
