Is sparkling water bad for you?

The fear: that sparkling water quietly wrecks your teeth

Switch from soda to sparkling water and someone will tell you that you haven't actually fixed anything, since both drinks are carbonated and carbonation means acid. The comparison sounds reasonable on its face. A new study out of Purdue gives the first real, if small, answer to whether that is true.

What the new study actually measured

In July 2026, Purdue nutrition researchers gave 20 adults four drinks on separate days: sugar-sweetened soda, plain unsweetened sparkling water, calcium-fortified sparkling water, and still water as a baseline. Rather than just testing the acidity of the drinks themselves, they measured each person's actual saliva afterward, a better proxy for what happens inside a real mouth. Soda dropped salivary pH the hardest and kept it low at both 2 and 20 minutes. Both sparkling waters caused only a brief dip, at 2 minutes for the plain version and 5 minutes for the calcium-fortified one, and both had returned close to normal within 20 minutes. Crucially, pH never fell below about 5.5, the rough point where enamel is thought to start softening.

"Our findings suggest that unsweetened sparkling water may be a lower-risk alternative to soda," said Wajiha Zulfiqar, the Purdue graduate student who led the work, presented at the NUTRITION 2026 conference. That is a real finding, but a modest one: the study has not been peer reviewed, it used 20 people, and it tracked saliva chemistry for 20 minutes, not actual enamel loss over years. [[INLINE]]

Dr. Rhona Eskander, a dentist who was not involved in the research, welcomed the result without calling it a green light. "I'd be cautious about calling it completely harmless," she said, adding, "this is a reassuring finding, but it's still only one piece of the puzzle." Her bigger concern is habit, not a single glass: someone who sips a can across an entire afternoon gives their saliva far less time to neutralize and recover than someone who drinks it with a meal and moves on. Flavored versions add another variable, since citric acid and fruit juice can push the pH lower and keep it there longer than the plain carbonation studied here.

The bloating complaint, explained

The other common complaint, that sparkling water bloats you, has a simpler explanation than any teeth debate: it is the bubbles. Carbonation introduces gas into your digestive tract, and in people prone to reflux or an irritable gut, that gas has to work its way out before you feel comfortable again. This is a mechanical effect, not evidence that sparkling water is somehow toxic. If a cold glass of seltzer leaves you uncomfortable twenty minutes later, you are reacting to dissolved CO2, the same thing that makes you burp after a beer, not to any hidden additive.

The bone myth that will not die

Sparkling water has also been accused of leaching calcium from your bones, an idea that traces back to confusing phosphoric acid, an ingredient in dark colas, with the carbonic acid that simply gives any seltzer its fizz. Carbonic acid is weak and short-lived in the body; it does not behave like the phosphate additives in cola. Nutritionists have been debunking this one for years, and nothing in the new Purdue data changes that picture.

Who should actually be careful

People with acid reflux, a diagnosed swallowing or motility issue, or already-compromised teeth (thin enamel, existing erosion, dry mouth from medication) are the ones who should treat any carbonated drink, sparkling water included, with more caution than the average healthy adult. For everyone else, the practical lesson from this study is about pattern, not the drink itself: finish a glass in one sitting rather than nursing it for hours, choose plain over flavored if your teeth are already a concern, and keep your normal brushing and rinsing habits.

Our take

Plain sparkling water is not the enamel bomb its critics claim, and the new Purdue data, preliminary as it is, backs up what the diet soda research has shown for years: sugar and added acid are doing most of the damage in a typical can of soda, not carbonation on its own. Treat sparkling water like any other mildly acidic drink: finish it with a meal, skip the all-day sipping, and save the real worry for the cans with sugar in them.

This is general information, not medical advice. Talk to a clinician before changing anything, especially if you are pregnant, nursing, or managing a condition.