Many people who want a healthier lifestyle have started replacing soft drinks with sparkling water.
It has bubbles like soda but usually contains no sugar and no calories. Even so, many people worry that the fizz and mild acidity could damage their teeth.
A new study from Purdue University offers reassuring news by showing that unsweetened sparkling water appears to be much gentler on teeth than sugar-sweetened soft drinks.
The research will be presented at NUTRITION 2026, the annual meeting of the American Society for Nutrition.
Healthy teeth are protected by a hard outer layer called enamel. Although enamel is the strongest material in the human body, it can slowly wear away when it is repeatedly exposed to acid. Dentists know that when the pH inside the mouth falls below about 5.5, enamel begins to lose minerals.
Over many months or years, repeated acid attacks can increase the risk of tooth sensitivity, cavities, and permanent enamel erosion.
Soft drinks are well known for causing this problem because they often contain both acids and large amounts of sugar. Sugar feeds bacteria living in dental plaque, allowing them to produce even more acid after a drink is finished.
This means sugary drinks can affect teeth in several different ways at once. Sparkling water is also slightly acidic because it contains dissolved carbon dioxide, but it does not contain added sugar.
To better understand the difference, researchers recruited 20 adults and asked each person to drink several different beverages during separate testing sessions. The volunteers drank plain water, sugar-sweetened soda, regular sparkling water, and calcium-fortified sparkling water.
Using the same people for every drink allowed the scientists to make fair comparisons because each volunteer acted as their own control.
The team measured saliva pH before drinking and then again at different times afterwards. Unlike earlier studies that only tested the acidity of the drinks themselves, this research examined what actually happened inside the mouth after each beverage was consumed. This provides a better picture of how saliva responds during everyday drinking.
The results showed that sugary soda produced the largest drop in mouth pH. Sparkling water also caused a temporary fall, but the change was much smaller than the one caused by soda. Calcium-fortified sparkling water produced a similar short-term effect, although the timing differed slightly.
Importantly, saliva quickly restored the mouth to near normal conditions. Within about 20 minutes after drinking sparkling water or soda, saliva had raised the pH close to its starting level. Throughout the study, the average pH remained above the level normally linked with enamel damage.
The researchers caution that these findings only describe short-term changes. Real-life dental health depends on how often people drink acidic beverages, whether they sip them slowly over long periods, how much sugar they contain, and how well they brush and floss their teeth.
Someone who drinks sugary soda many times a day may face a much higher risk than someone who occasionally drinks sparkling water.
The findings suggest that replacing sugary soft drinks with unsweetened sparkling water could reduce the risk of enamel erosion while still allowing people to enjoy a fizzy drink. The researchers also believe beverage companies could develop products that are even kinder to teeth by adjusting their ingredients.
In my view, this is a useful study because it looked at the mouth’s real response instead of simply measuring beverage acidity. However, the study involved only 20 participants and examined only immediate effects, so it cannot show what happens after years of daily use.
Larger, longer studies will be needed before firm conclusions can be made, but the evidence supports choosing unsweetened sparkling water over sugary soda as the healthier option for most people.
If you care about tooth health, please read studies about an important causes of tooth decay and gum disease, and common tooth disease that may increase risks of dementia.
For more health information, please see recent studies about mouthwash that may increase your tooth damage, and results showing this diet could help treat gum disease.
Source: Purdue University.
