Poorer people get access to less diverse foods and more likely to have much more stressful lives than affluent people. Shocker.
Also that poorer people often eat more Ultra Processed foods, because it’s often cheaper and saves time. https://www.bbc.co.uk/future/article/20260220-how-ultra-processed-foods-influence-our-gut-microbiome
I think emulsifiers can be particularly bad, I think for several reasons, some might be bad for gut bacteria if I recall, but they also can break down the blood brain barrier, and destroy the barrier in the gut that prevents non nutrients from getting into the blood, as I understand it from what I had read.
Emulsifiers keep things from seperating, like peanut butter might have it to prevent the oil in it from separating onto the top. Ice cream might have it. Some are worse than others. Processed foods are really untrustworthy these companies have nothing but contempt for us.
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.