Here's proof that certain questions are best left unanswered: Curious if the bubbles in her beloved LaCroix and San Pellegrino were as tooth-decaying as sugary sodas, Atlantic health writer Olga Khazan did some research that she certainly now regrets. Her findings in a nutshell: Slowly but surely, an acid created by the carbonation will "wear away tooth enamel."
Like lots of things, the inquiry began innocently enough:
Dentists: Please settle this one for me -- is non-sugary, sparkling water (like La Croix) bad for your tooth enamel? Why or why not?
— Olga Khazan (@olgakhazan) January 26, 2016
Then the dentists started reaching out, and she started reviewing the literature on carbonic acid's link to tooth decay. By then, there was no coming back: Even unflavored sparkling water contains enough acid to slowly rot teeth, she learned. She writes the amount a person can safely drink "without risking Joker mouth" depends on other factors like how much sugar and acid are in that person's diet, their dental hygiene, and even whether they use a fluoridated toothpaste, but dentists tell her the safest option either way is to joylessly sip on plain flat water.
The little bit of good news is that this carbonic acid is "relatively weak":
Unless they're flavored with citric or other acids, seltzers tend to have more neutral pH values than soft drinks like Coke. While bottled flat water has a pH of about 7 — or totally neutral — that of Perrier is about 5.5.
But things look decidedly worse for those who prefer some flavor with their fizz:
The flavorings, though, can bring the pH down, making the beverages even harsher on tooth enamel. One 2007 study in which researchers exposed human teeth to flavored sparkling waters for 30 minutes found the waters to be roughly as corrosive as orange juice.
She concludes, "It would be inappropriate to consider these flavored sparkling waters as a healthy dental alternative to other acidic drinks." But one dentist assures her that fizzy water isn't going to be "a main cavity-causing factor" for average healthy adults who drink it in moderation, and for the seltzer-obsessed out there, he offers two tricks: "Dilute the carbonated water with regular water," or "just swish with regular water after." Easy enough, right?