Some good bacteria comes from vegetables that are uncooked. Broccoli is one but I think all of them. I don’t know to what degree that matters really though your flora is pretty well covered, like there isn’t any room for new bacteria to get a foothold when introduced unless you had antibiotics or your system was flushed.

But the diet of a wealthy person would lend itself to more better bacterias introduced. But a good share of your flora comes from your parents. A lot of what we once thought was genetic comes from the gut bacteria we picked up from our parents.