My immediate thought was "well, what do these bacteria feed on?".
The researchers found that healthier diets and lifestyle were associated with lower levels of imidazole propionate. Trying to starve the bacteria of precursors isn't practical.
Not starve them, but put them on a diet?
Low B6 will lead to increased histidine by inhibiting Histidine decarboxylase.
https://healthmatters.io/understand-blood-test-results/histi...