Xylitol was a heavy point of discussion in the Oral Health episode on @hubermanlab yesterday and it's time we refresh how exactly this compound works to stop cavities in their tracks.
Xylitol is a polyol, or a sugar alcohol. Immediately people have a knee-jerk reaction to scary sounding words that start with X, end in -ol, and associated with the word "sugar alcohol".
Nature disagrees with the dogmatic reflexive wincing as xylitol is found naturally in birch, berries, mushrooms, cauliflower and more.
Back to how this miracle sweetener prevents cavities:
-The main suspect in cavity formation is streptococcus mutans (bacteria)
- It feeds on sugar, and excretes acid which eats your tooth structure allowing strep mutans to tunnel deep into the tooth leaving behind a necrotic soup of cavity material
- Xylitol pretends to be a sugar, tricking the strep mutans into eating it, and since it's nonfermentable there's no acid production
- It's presence in the mouth prevents strep mutans replication and adherence to the tooth
- It stimulates saliva production which has tons of anti-cavity benefits and buffering capacity against acid
As if all of this wasn't incredible enough, xylitol is extremely selective at destroying the bad bacteria while sparing the beneficial bacteria of the mouth. It's the ultimate microbiome respecting, cavity preventing, sweet tasting compound on earth.

@hubermanlab As always, I must add: xylitol is toxic to animals. Especially dogs. There is a world in which you can enjoy the benefits of xylitol without putting your pets in danger, please be a responsible pet owner.