Is Sparkling Water Bad for Your Teeth? What Studies Show

The question is about erosion: acid softening and slowly dissolving the enamel, the hard outer layer of the tooth. Erosion is different from decay, which is caused by bacteria feeding on sugar. Carbon dioxide makes sparkling water slightly acidic, which is why people worry about it.

Plain sparkling water

A laboratory study compared mineral waters with soft drinks by measuring how much tooth mineral each dissolved. Sparkling mineral waters dissolved slightly more than still waters, but the levels remained low, roughly a hundredth of what the soft drinks dissolved¹.

Two further results help explain this. When the sparkling waters were de-gassed, they dissolved less, which the authors took to suggest that carbonation may not be an important factor in itself. In a separate experiment, adding calcium to purified water reduced dissolution the most, but other minerals such as magnesium and sulphate moderated the effect. That does not rank the brands on sale.

This was a laboratory study, not a study of people's teeth. Saliva, meals and how often you drink all affect what happens in the mouth, and they were not part of the test. We found no clinical or long-term study that followed the teeth of people who drink sparkling water. The laboratory results are the only evidence we found, not proof of what happens in your mouth.

Flavoured sparkling water

Flavoured sparkling waters, the kind with added fruit flavours, behaved very differently in a UK laboratory study. The drinks tested had a pH between 2.74 and 3.34², which is strongly acidic. Every drink put through the study's erosion test, which measured how much of a tooth-mineral substitute dissolved, showed an erosive potential similar to or greater than pure orange juice (89 to 143% of orange juice's). Orange juice is a drink already known to erode enamel. Extracted teeth showed surface changes after 30 minutes in the drinks.

The authors concluded that such drinks should be considered potentially erosive. The study's summary does not say which acid was responsible, or how many drinks were tested. Products on sale today may differ from those tested.

In practice: treat a flavoured sparkling water like a fruit juice, not like water. Check the label for added sugar too.

Compared with soft drinks and juice

• Plain sparkling water vs soft drinks. In one laboratory study, roughly a hundredth of the dissolution. Unsweetened sparkling water also adds no sugar. Decay is less common when sugars make up less than 10% of daily energy³. Swapping a sugary drink for plain water helps on both counts.
• Flavoured sparkling water vs orange juice. Similar or greater erosive potential in the laboratory.
• Plain sparkling vs still water. Slightly more dissolution for sparkling, at a low level.

None of these laboratory comparisons tells you how many glasses a day are too many; we found no study that measured that in people.

Drinking it with your teeth in mind

• If you enjoy plain sparkling water, the laboratory evidence gives no strong reason to give it up.
• Keep flavoured sparkling waters, juices and soft drinks to mealtimes rather than sipping them over hours.
• Have plain water, still or sparkling, between meals.
• Brush twice a day with fluoride toothpaste (1,350 to 1,500 ppm fluoride for adults), once last thing at night, and spit out rather than rinse⁴. In adults, fluoride toothpaste reduced new decay compared with toothpaste without fluoride⁵.
• Keep to check-ups; a dentist can check for signs of erosion.

When to see a dentist

Book an examination if:

• your teeth have become sensitive to cold, hot or sweet;
• the biting edges of your front teeth look thin, see-through or chipped;
• your teeth look more yellow than they used to, or fillings seem to stand up from the tooth surface;
• you drink acidic drinks often and have not had a check-up for a while.

Emergencies. Increasing tooth pain, facial swelling or a fever: see a dentist without waiting. Swelling that makes it hard to breathe, speak or swallow⁶, swelling that spreads to your eye or neck, a lot of swelling inside your mouth, or difficulty opening your mouth: go to an emergency department or call 112.

Frequently asked questions