A recent article in the LA Times discusses the idea that our modern lifestyle is causing a progressive thinning out of the variety of microbes that are present in our guts, and this might be a bad thing.
Author: ibsrecoveryroot2
Leafy green vegetables promote healthy gut bacteria
Leafy green vegetables contain sulfoquinovose which feeds various gut bacteria, and the researchers seem to think this is good bacteria. However I would note that sulfur-containing food sources promote hydrogen sulfide gas in the gut which is unhealthy. So all in moderation!
Sweet discovery in leafy greens holds key to gut health