(P18-40-26) Are Unsweetened Sparkling Waters a Safer Alternative to Soda? A Salivary pH Investigation

Objectives: Sugar-sweetened sodas contribute to dental erosion, lowering oral pH below the critical value of 5.5, but less is known about the erosive potential of unsweetened sparkling waters. The objective of this study is to observe pH dynamics of beverages in vitro and then compare in vivo changes in salivary pH during and after consumption of a sugar-sweetened soda, unsweetened sparkling waters (one fortified with calcium), and plain water.

Methods: For the in vitro test, pH measurements were taken at 0, 2, 5, 10, and 20 minutes after opening the beverages. Next, using a randomized within-subjects crossover design, healthy adults (18–50 years old) completed four study visits, during each of which they consumed a 12-oz beverage over 10 minutes. Exclusion criteria included use of medications, dental disease, recent dental visit, type 1 or type 2 diabetes, and pregnancy. Saliva samples were collected at baseline (0), during consumption (2,5 min), at the end of consumption (10 min), and after consumption (20 min) to characterize pH trajectories and buffering dynamics. In vitro data were analyzed using ANOVA, while in vivo data used a linear mixed-effects model including beverage, time, and their interaction, with change in pH as the outcome.

Results: In vitro pH data indicate that the lowest pH was observed in soda, followed by unsweetened sparkling water, then unsweetened sparkling water with calcium, and finally plain water; these patterns were consistent across all time points. In vivo, 12 participants (9 female, 3 male) completed the study. Sugar-sweetened soda induced the lowest salivary pH, significantly lower than water at 2 and 20 min. Unsweetened sparkling water without calcium showed a lower salivary pH than water only at 2 min. For all beverages tested, salivary pH remained above the critical threshold for enamel demineralization (pH=5.5).

Conclusions: Overall, sugar-sweetened soda lowered salivary pH more than unsweetened sparkling waters and plain water. These findings support current recommendations of reducing the intake of sugar-sweetened sodas, and unsweetened sparkling water may be a reasonable alternative when consumed in moderation.

Funding Sources: No external funding