Cohort studyindependent cross-checkabstract checked★ key study I-SOD-108 in-depth review
Soda linked to more heartburn in women
Association Between Beverage Intake and Incidence of Gastroesophageal Reflux Symptoms.
Overview
Mehta RS et al.. Clin Gastroenterol Hepatol 2020 · PMID 31786327 · DOI 10.1016/j.cgh.2019.11.040
In 48,000 US nurses, women drinking the most soda developed weekly heartburn or regurgitation about 29% more often; switching soda for water was linked to lower risk.
Does the study support the specific claim? Partly · Methodological quality: high
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Examine which drinks predict new reflux symptoms.
- How was the study done?
Followed women for many years with food questionnaires.
- How many people, animals or samples were studied?
48,308 women; 7961 developed reflux symptoms.
- What was actually found?
Coffee, tea and soda were linked to more reflux symptoms; water, milk and juice were not.
- How large was the observed effect?
Soda HR 1.29 (1.05-1.58) at the highest intake.
- What do the results mean in everyday life?
People with heartburn may benefit from replacing soda with water.
- What are the study's limitations?
Observational; self-reported symptoms; women only.
- What does it say about Elawady's specific claim?
Supports the reflux part of the claim, not the ulcer part.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Cannot prove soda causes reflux disease or damage.
Scientific in-depth review
1. Full reference
- Authors
- Mehta RS et al.
- Journal
- Clin Gastroenterol Hepatol
- Year
- 2020
- Identifier
- PMID 31786327 DOI 10.1016/j.cgh.2019.11.040
- Verification
- verified – PubMed efetch 2026-10-26 + Crossref 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
NIH-funded (PubMed record); disclosures not reviewed
2. Research question
Is intake of coffee, tea, soda and other beverages associated with incident GER symptoms?
3. Study design and population
- Study design
- Cohort study – Prospective cohort (Nurses' Health Study II) with Cox models and substitution analysis
- Population
US women aged 42-62 without regular GER symptoms, cancer or acid-suppressant use
- Country
USA
- Period
NHS II follow-up
- Sample size
48,308 women; 7961 incident cases; 262,641 person-years
- Inclusion and exclusion criteria
Free of regular GER symptoms, no PPI/H2RA use
4. Methods and endpoints
- Exposure / intervention
Beverage servings/day (FFQ)
- Comparator
0 servings/day
- Endpoints
GER symptoms (heartburn or regurgitation) at least weekly
- Statistical methods
Multivariable Cox; substitution models
5. Actual results
- Results
Highest (>6 servings/day) vs lowest (0) intake: soda HR 1.29 (1.05-1.58; P trend <.0001), coffee 1.34 (1.13-1.59), tea 1.26 (1.03-1.55). No association for milk, water or juice. Replacing 2 servings/day of soda with water: HR 0.92 (0.89-0.96). Similar by caffeine status.
- Absolute risks
not reported; illustrative calculation in stats/C-SOD-12_reflux.py
- Authors' conclusion
Intake of coffee, tea or soda was associated with increased risk of GER symptoms; drinking water instead reduced risk.
6. Strengths
- Large prospective cohort
- Dose-response
- Substitution analysis
7. Weaknesses
- Self-reported symptoms
- Women only, mostly white health professionals
- Highest category (>6/day) is extreme
8. Risk of bias
- Orienting tool
- ROBINS-E
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Residual confounding possible; outcome self-reported.
9. Assessment of the statistical interpretation
Modest relative association at very high intake; CIs log-symmetric. Absolute excess at 30 per 1000 person-years baseline is about 9 per 1000 person-years if HR 1.29 applied (approximation).
10. Relevance to the specific claim
Supports the reflux/heartburn part of C-SOD-12 as a modest association; does not address gastritis, ulcers or 'wrecking digestion'.
11. Independent contrary findings
Johnson 2010 review (I-SOD-01) found no direct evidence that carbonated drinks cause GERD complications.
12. Transferability to Germany and Europe
Applicable.
13. Overall methodological judgement
Best prospective evidence that soda is associated with more reflux symptoms; effect modest.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | high |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | consistent |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Whether carbonation, acidity, caffeine or sugar drives the association.