I think you asked an interesting question, furthermore, not many answers are coming to mind. Off the top of my hat, caffeine dulls it, right? Works against kava. Can this be said?
I've found that super spicy peppers don't block Kava's actions. Sometimes cannabinoids, full spectrum, can mop up the effects of kava rather hastily. have you noticed this? maybe it is due to metabolic tempo. CB have a lot to do with metabolism and digestion.
I wil! let you know if I think of anything.