Measurement / residue studyindependent cross-checkabstract checked★ key study I-SOD-114 in-depth review
Colas are strongly acidic; sparkling water is not
The pH of beverages in the United States.
Overview
Reddy A et al.. J Am Dent Assoc 2016 · PMID 26653863 · DOI 10.1016/j.adaj.2015.10.019
Measured pH: Pepsi 2.39 and Coca-Cola 2.37 (strongly acidic), plain sparkling mineral water 5.25.
Does the study support the specific claim? No · Methodological quality: moderate
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Measure acidity of beverages.
- How was the study done?
Laboratory pH measurements.
- How many people, animals or samples were studied?
379 beverages.
- What was actually found?
Most drinks are acidic; colas among the most acidic; sparkling mineral water much less.
- How large was the observed effect?
Pepsi pH 2.39; Perrier 5.25.
- What do the results mean in everyday life?
Cola is acidic and erosive to teeth; it cannot neutralise stomach acid.
- What are the study's limitations?
pH alone does not determine erosion.
- What does it say about Elawady's specific claim?
Contradicts the bicarbonate claim; supports tooth-damage claim.
- Do the results apply to Germany and Europe?
Same brands sold in Europe and Egypt.
- What can explicitly not be concluded from this study?
Cannot measure effects inside the body.
Scientific in-depth review
1. Full reference
- Authors
- Reddy A et al.
- Journal
- J Am Dent Assoc
- Year
- 2016
- Identifier
- PMID 26653863 DOI 10.1016/j.adaj.2015.10.019
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref 2026-10-26
- Retracted
- no
- Corrections
Crossref lists a publisher erratum (10.1016/j.adaj.2016.08.021; J Am Dent Assoc 2016;147:781); content of the erratum not retrieved. PubMed CommentsCorrections lists none.
- Extent checked
- abstract only
- Conflicts of interest and funding
NIH (NIDCR) grants; authors report no conflicts of interest (full text)
2. Research question
What is the erosive potential, measured by pH, of beverages sold in the United States?
3. Study design and population
- Study design
- Measurement / residue study – Laboratory measurement of pH of 379 commercially available beverages (triplicate, 25 C)
- Population
Not applicable (beverages)
- Country
USA (Birmingham, Alabama)
- Period
2015
- Sample size
379 beverages
- Inclusion and exclusion criteria
Commercially available beverages
4. Methods and endpoints
- Exposure / intervention
Beverage type
- Comparator
Not applicable
- Endpoints
pH
- Statistical methods
Mean (SD) of triplicate measures
5. Actual results
- Results
93% of beverages had pH <4.0; 39% extremely erosive (pH <3.0). Full-text table (PMC4808596, checked 2026-10-26): Pepsi pH 2.39 +- 0.03; Coca-Cola Classic 2.37 +- 0.03; Perrier carbonated mineral water 5.25 +- 0.10; Canada Dry Club Soda 5.24 +- 0.03.
- Absolute risks
not applicable
- Authors' conclusion
Most commercially available beverages are potentially erosive to the dentition.
6. Strengths
- Large number of products
- Standardised measurement
7. Weaknesses
- pH is only one determinant of erosion
- US products; formulations may differ elsewhere
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- low
- Rationale
Simple measurement study.
9. Assessment of the statistical interpretation
Colas are about 700 times more acidic (hydrogen-ion concentration) than plain sparkling water (stats/C-SOD-14_sparkling.py).
10. Relevance to the specific claim
C-SOD-13: colas are strongly acidic (pH ~2.4), incompatible with the claim that they contain bicarbonate that neutralises stomach acid. C-SOD-11: soft drinks are erosive. C-SOD-14: plain sparkling water is only weakly acidic (pH ~5.2).
11. Independent contrary findings
None.
12. Transferability to Germany and Europe
Major cola brands are sold worldwide; local formulations may vary slightly.
13. Overall methodological judgement
Reliable product measurements; central for the chemistry claims.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | low |
| Precision of results | high |
| Directness | direct |
| Reproducibility | replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Egyptian product measurements.
15. Linked fact checks
- Elawady: the harm of soda is the carbonated water itself, not the sugar or sweetener; one 300 ml Pepsi delivers more carbon dioxide than the body produces in a whole day, and colas contain sodium bicarbonate that neutralises stomach acid and increases reflux. – Studies contradicting or limiting the claim
- Soft drinks cause tooth decay. – Studies supporting the claim
- All carbonated waters of every kind (including unsweetened sparkling water) are harmful and must be avoided. – Studies contradicting or limiting the claim