Research finds unsweetened sparkling water less harmful to oral pH than soda — Evidence Review

A new study from Purdue University finds that unsweetened sparkling water causes only a brief and modest drop in oral pH, much less than sugar-sweetened soda. Most related research supports this conclusion, indicating that sparkling water is less erosive to tooth enamel than sugary or highly acidic beverages.

• Multiple studies confirm that sparkling and mineral waters generally have a far lower erosive potential than sodas or juice, especially when no sugar is present, and their effects on enamel are minimal compared to sugary carbonated drinks 1 3.
• Research consistently shows that sugar and acidity in soft drinks are major contributors to dental erosion, while unsweetened sparkling water produces only transient and mild pH reductions, unlikely to cause enamel damage under normal consumption patterns 2 5 11.
• Flavored or highly acidic sparkling waters may pose greater risks, but plain unsweetened sparkling water is repeatedly identified as a safer alternative for dental health relative to sodas and energy drinks 1 4 13.

Study Overview and Key Findings

With the rising popularity of sparkling water as an alternative to soda, questions have emerged about the potential impact of carbonated beverages on dental health. This study is notable for directly comparing the short-term effects of unsweetened sparkling water, sugar-sweetened soda, calcium-fortified sparkling water, and plain water on oral pH levels in real time, rather than relying solely on the acidity of the drinks themselves. The research aims to provide a clearer understanding of how these beverages influence conditions in the mouth that could lead to enamel erosion.

Property	Value
Organization	Purdue University
Authors	Wajiha Zulfiqar
Population	20 adults
Sample Size	20 adults
Methods	Non-randomized Controlled Trial (Non-RCT)
Outcome	Oral pH changes after consuming different beverages
Results	Unsweetened sparkling water lowers pH less than sugar-sweetened soda.

The study, presented at the American Society for Nutrition’s NUTRITION 2026 annual meeting, found that while both soda and sparkling water temporarily lower oral pH, soda causes a much greater and more prolonged drop. In contrast, unsweetened sparkling water only briefly reduces oral pH, which returns to baseline within 20 minutes due to the buffering effect of saliva. Importantly, after drinking sparkling water, the pH remained above the threshold (5.5) associated with enamel demineralization, suggesting a lower risk of dental erosion compared to soda. The authors note that enamel erosion risk also depends on consumption frequency and duration of exposure, highlighting the importance of moderation and good oral hygiene.

Literature Review: Related Studies

To contextualize these findings, we searched the Consensus paper database, which contains over 200 million research papers. The following search queries were used to identify relevant studies:

1. sparkling water dental health effects
2. carbonated drinks tooth enamel erosion
3. pH levels sparkling water soda comparison

Below, we organize the main topics and findings from the related literature:

Topic	Key Findings
Does plain sparkling water pose a meaningful risk to tooth enamel?	- Mineral and sparkling waters have much lower erosive potential than sodas; carbonation alone is not a significant risk factor 1 13. - Salivary pH after sparkling water consumption remains above the critical threshold for enamel dissolution 5 11.
How do sugar and acidity in soft drinks contribute to dental erosion?	- Sugar-sweetened and acidic soft drinks cause significant drops in oral pH, promote bacterial growth, and contribute strongly to dental erosion and caries risk 2 3 8 11. - Buffering capacity and titratable acidity in sodas and fruit-based drinks prolong oral acidity, increasing risk 10 12.
Are flavored or fortified sparkling waters as safe as plain sparkling water?	- Flavored sparkling waters often have low pH and appreciable acidity, sometimes comparable to fruit juices, and can erode enamel to a greater extent than plain sparkling water 4 13. - Addition of minerals like calcium may reduce, but not eliminate, erosive potential 1.
Can saliva protect against short-term acid exposure from beverages?	- Saliva usually restores pH to safe levels within minutes, mitigating short-term effects of mildly acidic drinks 5 11. - Frequency and context of consumption (e.g., at bedtime) influence cumulative erosion risk 7 9.

Does plain sparkling water pose a meaningful risk to tooth enamel?

Research consistently shows that plain (unflavored, unsweetened) sparkling water has a much lower potential to erode tooth enamel compared to sugar-sweetened sodas or acidic juices. In vitro and in vivo studies indicate that, although sparkling water is slightly more erosive than still water, its effect is minimal and oral pH rarely drops below the critical point for demineralization 1 13. The new study aligns with these findings by demonstrating only a brief and modest pH reduction after sparkling water consumption.

• Plain sparkling and mineral waters cause little to no enamel dissolution, especially compared to sodas and juices 1.
• Salivary pH after sparkling water consumption typically stays above critical levels for enamel damage 5 11.
• Carbonation alone is not a major risk factor for erosion in the context of plain sparkling water 1 13.
• The new study’s direct measurement of in-mouth pH supports the consensus that unsweetened sparkling water is a lower-risk alternative to soda.

How do sugar and acidity in soft drinks contribute to dental erosion?

The literature strongly supports the association between sugar, high acidity, and dental erosion in soft drinks. Both the presence of fermentable sugars and low pH contribute to a significant and sustained drop in oral pH, promoting enamel demineralization and bacterial proliferation 2 3 8 11. The new study’s finding that sugar-sweetened soda produces a deeper and longer-lasting pH drop is consistent with these results.

• Sugar-sweetened sodas and acidic drinks are major contributors to dental erosion and caries, especially with frequent consumption 2 3 8 11.
• Buffering capacity and titratable acidity in many soft drinks prolong the period of low oral pH, increasing erosion risk 10 12.
• Oral exposure time and frequency of consumption amplify risk, particularly for children and adolescents 2 7.
• The new study’s focus on real-time pH changes after beverage consumption gives practical insight into these well-established processes.

Are flavored or fortified sparkling waters as safe as plain sparkling water?

Not all sparkling waters are the same. Studies show that flavored sparkling waters often have a lower pH and higher titratable acidity, sometimes matching or exceeding the erosive potential of fruit juices 4 13. While mineral enrichment (such as with calcium) can reduce erosiveness, these beverages should not be presumed as safe as plain sparkling water.

• Flavored sparkling waters can cause enamel dissolution similar to or greater than orange juice 4.
• Mineral fortification lowers, but does not fully eliminate, erosive potential, with calcium having the most protective effect 1.
• Consumers may misinterpret flavored sparkling waters as being as safe as water, which is not always the case 4 13.
• The new study’s inclusion of calcium-fortified sparkling water addresses this distinction, showing a slightly delayed but still temporary pH drop compared to regular sparkling water.

Can saliva protect against short-term acid exposure from beverages?

Saliva’s natural buffering capacity usually restores oral pH to baseline within minutes after exposure to mildly acidic drinks, limiting potential enamel damage 5 11. However, studies highlight that risks increase with frequent, prolonged, or bedtime consumption when saliva flow is reduced 7 9. The new study’s observation of rapid pH normalization after sparkling water or soda consumption underscores the importance of these factors.

• Saliva helps maintain oral pH above erosive levels after brief exposures, especially with non-sugary, mildly acidic drinks 5 11.
• Frequent, prolonged, or bedtime consumption of acidic beverages increases cumulative erosion risk 7 9.
• The protective effect of saliva may be insufficient with repeated or high-frequency exposures 7 9.
• The new study’s short-term design does not address long-term or cumulative effects, highlighting an area for further research.

Future Research Questions

While the new study provides valuable insight into the short-term effects of different beverages on oral pH, several questions remain open, particularly regarding long-term outcomes and the effects of different formulations. Future research should address these gaps to inform public health guidance and beverage industry practices.

Research Question	Relevance
What are the long-term effects of regular sparkling water consumption on tooth enamel?	Existing studies focus on short-term or in vitro effects; the cumulative impact of daily sparkling water intake over years is unknown. Long-term data are essential for evidence-based dietary recommendations 3 7.
How do flavored or acidified sparkling waters compare to plain sparkling water in terms of dental erosion risk?	The new study focuses on unsweetened sparkling water, but many popular brands are flavored or acidified, which may increase erosive potential 4 13. Comparing these products is important for consumer safety.
Does calcium fortification in sparkling water provide significant protection against enamel erosion?	Some studies suggest added minerals reduce erosion, but the magnitude and clinical relevance of this effect require further investigation 1. Understanding this could guide beverage formulation.
What role does consumption frequency and drinking pattern play in the erosive potential of carbonated beverages?	The risk from occasional versus frequent or prolonged exposure is not fully understood; patterns such as sipping over long periods or drinking at bedtime may increase risk despite low inherent erosiveness 7 9.
Do unsweetened carbonated drinks affect other aspects of oral health, such as microbiome composition or gum health?	Most studies focus on enamel, but effects on oral bacteria and soft tissues are less well studied. Exploring these outcomes could reveal additional benefits or risks of carbonated beverage consumption 11.