Early findings presented at the American Society for Nutrition’s NUTRITION 2026 meeting indicate unsweetened sparkling water caused a smaller, short-lived increase in mouth acidity compared with sugar-sweetened soda in a small adult study.
A small, preliminary study in 20 adults found sugar-sweetened soda led to the largest and most persistent increase in mouth acidity, while unsweetened sparkling waters were associated with shorter-lived changes.
In the experiment, participants drank four beverages—sugar-sweetened soda, regular unsweetened sparkling water, calcium-fortified sparkling water and plain water—and researchers tracked salivary pH over the minutes that followed. Soda produced the strongest effect, with salivary pH remaining significantly lower than after plain water at both two minutes and 20 minutes.
Regular unsweetened sparkling water was linked to a temporary drop in salivary pH at two minutes, and calcium-fortified sparkling water showed a decrease at five minutes. For both sparkling waters, pH returned to nearly its starting level within 20 minutes.
In all cases, salivary pH stayed above about 5.5, a level commonly associated with the point at which tooth enamel can begin to dissolve.
"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 and alongside good oral hygiene practices," said Wajiha Zulfiqar, a graduate student in Nutrition Science at Purdue University.
Zulfiqar presented the research on Sunday, July 26, 2026, at NUTRITION 2026, the American Society for Nutrition’s annual meeting held July 25–28 in National Harbor, Maryland.
The researchers noted the work measured only short-term changes in salivary pH. They said real-world risk of enamel erosion can also depend on factors such as how often someone drinks a beverage, how long teeth are exposed, and whether the drink contains sugar. The results are considered preliminary because conference abstracts typically have not completed the full peer-review process required for publication in a scientific journal.
