you are right to underline the link between having some form of intestinal inflammation and B12 deficiency: I was recently diagnosed as having insufficient level of B12, which is a typical symptom of Crohn's disease, dysbiosis and colitis.
I refused injections of B12 prescribed by a doctor--I am allergic, there are side effects and anyway, vitamins found in food are more easily absorbed.
I said I would try to get the B12 I need naturally. Liver is a very good source but yuck! I ordered a kind of seaweed named dulce, it's supposed to be very rich in B12. Any suggestions about foods rich in B12 is welcome.