>>Do you chew gum? If so, why?

I chew xylitol gum before any procedure at the dentist's. I suspect I have more motivation than many as I came very close to not surviving a brain infection with that streptococcus mutans - which seemed to come from a dental cleaning (an utterly uneventful one). Before anyone decides to forgo cleanings, my brain surgeon tells me I am more likely to be struck by lightning — or win the lottery — than for this to happen to me again. Still, I chew xylitol gum.

To the extent that bacterial aerobic respiration works like ours (pretty sure it is), xylitol is doing more than just not providing calories s. mutans can use - there's an attempt to metabolize it, which costs ATP - and nothing comes back, so it's draining energy reserves, possibly causing cell death. FWIW, this is why xylitol is so dangerous to dogs; it does the same thing in their livers. Meanwhile we're fine as we can't absorb it.

I got curious as to whether that xylitol was doing damage to my microbiome, did a bit of digging. It turns out that it's a net positive for the microbiome, increasing the population of one of the 'good' bacteria. There are quite a few studies out there; here's the first one that came up in a search: Xylitol enhances synthesis of propionate in the colon via cross-feeding of gut microbiota.

Also, I find it interesting that the Finns chewed gum from birch bark. As you may or may not know, most xylitol is produced from birch. Probably just a coincidence…