Unsweetened sparkling water may be a better option for your teeth than sugary sodas, according to a preliminary study comparing how some popular drinks affect acidity in your mouth.
When the pH of your mouth drops below about 5.5, tooth enamel can begin to dissolve. New findings suggest that carbonated water may temporarily lower oral pH, but the effect appears to be less pronounced than the reduction caused by carbonated drinks.
“Many people are switching from soda to sparkling water, and our findings suggest that unsweetened sparkling water may be a lower-risk alternative to soda when consumed in moderation, along with good oral hygiene habits,” said Wajiha Zulfiqar, a graduate student in nutritional sciences at Purdue University.
Zulfiqar presented the results at NUTRITION 2026, the American Academy of Nutrition’s flagship annual meeting, held July 25-28 in National Harbor, Maryland, outside Washington, DC.
Comparison of carbonated water and soda
Previous research has shown that sugary sodas can lower the pH in your mouth to below 5.5, which can promote tooth erosion. Little is known about how unsweetened carbonated water affects acidity in the mouth.
For the study, researchers tested sugary soda, regular carbonated water, calcium-fortified carbonated water, and plain water on 20 adults. By having all participants drink their own drinks, the team was able to reduce the impact of natural differences between individuals.
Rather than relying solely on the acidity of the drink itself, the researchers measured the pH of saliva. This allowed us to observe how the mouth reacts immediately after drinking the drink.
“By directly comparing different beverages using the same experimental framework, we were able to assess the effects of carbonated water in comparison to both soda, a high-risk beverage, and plain water as a neutral standard,” Zulfikar said. “Furthermore, by measuring how the mouth reacts in real time, rather than just testing the acidity of beverages as other studies have done, our study provides a more realistic understanding of how these beverages may impact oral health.”
Soda caused the greatest pH drop
Of the beverages tested, soda caused the greatest increase in mouth acidity. Salivary pH was significantly lower after soda than after water at both 2 and 20 minutes after ingestion.
Regular unsweetened carbonated water temporarily lowered the pH of saliva after 2 minutes. Calcium-fortified carbonated water decreased after 5 minutes. For both types of carbonated water, the pH returned to near starting levels within 20 minutes.
Saliva also helped restore normal acidity after participants drank soda or carbonated water. In the short term, pH remained above thresholds associated with enamel damage.
The researchers emphasized that the experiment was able to measure only short changes in saliva pH. The likelihood of tooth erosion in daily life is also influenced by how often you drink drinks, how long your teeth are exposed to the drink, and whether the drink contains sugar.
Potentially Safer Soda Alternatives
“Our findings suggest that replacing sugary carbonated drinks with unsweetened carbonated water may reduce the risk of enamel erosion,” Zulfikar said. “These results highlight an opportunity for the beverage industry to explore reformulation strategies that can potentially reduce the erosion potential of acidic beverages.”
The research team will next investigate the long-term effects of carbonated water on oral health. Future research may determine whether other features of the mouth that contribute to the health of teeth and gums change.
Zulfiqar presented this research (abstract) at the Clinical Nutrition II Poster Session on Sunday, July 26, at the Gaylord National Resort & Convention Center.
Abstracts presented at NUTRITION 2026 were reviewed and selected by a panel of experts. However, the peer review process required for publication in scientific journals is usually not completed. Therefore, findings should be considered preliminary until published in a peer-reviewed publication.
