Meta-analysisindependent cross-checkabstract checked I-DRY-117 standard review
Yogurt and fermented milk do not raise inflammation
Effects of fermented dairy products on inflammatory biomarkers: A meta-analysis.
Overview
Zhang X et al.. Nutr Metab Cardiovasc Dis 2023 · PMID 36710113 · DOI 10.1016/j.numecd.2022.12.014
CRP slightly lower (SMD -0.21) across 14 trials.
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?
Test fermented dairy and inflammation.
- How was the study done?
Meta-analysis of trials.
- How many people, animals or samples were studied?
14 trials.
- What was actually found?
CRP slightly down; most markers unchanged.
- How large was the observed effect?
CRP SMD -0.21.
- What do the results mean in everyday life?
Yogurt does not inflame.
- What are the study's limitations?
Few small trials.
- What does it say about Elawady's specific claim?
Contradicts the claim.
- Do the results apply to Germany and Europe?
Applicable.
- What can explicitly not be concluded from this study?
Cannot show disease outcomes.
Scientific in-depth review
1. Full reference
- Authors
- Zhang X et al.
- Journal
- Nutr Metab Cardiovasc Dis
- Year
- 2023
- Identifier
- PMID 36710113 DOI 10.1016/j.numecd.2022.12.014
- Verification
- verified – PubMed efetch 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
No conflicts declared.
2. Research question
Do fermented dairy products change inflammatory biomarkers?
3. Study design and population
- Study design
- Meta-analysis – Meta-analysis of controlled trials (PubMed, Web of Science, Embase, Cochrane)
- Population
Adults in trials
- Country
Multinational
- Period
to 2022
- Sample size
14 trials (15 arms): yogurt 9, fermented milk 4, kefir 2
- Inclusion and exclusion criteria
Trials of fermented dairy
4. Methods and endpoints
- Exposure / intervention
Yogurt, fermented milk, kefir
- Comparator
Control
- Endpoints
CRP, IFN-gamma, TNF-alpha, IL-6, IL-10, IL-2
- Statistical methods
Random/fixed effects SMD
5. Actual results
- Results
CRP SMD -0.21 (-0.40 to -0.02); IFN-gamma SMD +0.12 (0.01-0.23); no significant effect on TNF-alpha, IL-6, IL-10, IL-2. CRP decreased in participants with metabolic diseases.
- Absolute risks
not reported
- Authors' conclusion
Fermented dairy reduced CRP and increased IFN-gamma but had no effect on other markers; interpret with caution.
6. Strengths
- Trial-based
7. Weaknesses
- Small number of trials
- Surrogate markers
- SMD hard to interpret clinically
8. Risk of bias
- Orienting tool
- AMSTAR 2
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Limited literature.
9. Assessment of the statistical interpretation
Small standardised effects.
10. Relevance to the specific claim
Fermented dairy, including yogurt that the system forbids, did not increase inflammatory markers and slightly lowered CRP.
11. Independent contrary findings
None found showing pro-inflammatory effects of yogurt in non-allergic people.
12. Transferability to Germany and Europe
Applicable.
13. Overall methodological judgement
Consistent with I-DRY-18/19.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | direct |
| Reproducibility | unknown |
| Consistency with the overall evidence | consistent |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Clinical relevance.
15. Linked fact checks
- Dairy products harm health and cause inflammation. – Studies contradicting or limiting the claim
- Cooked/processed and aged cheese is the more digestible form of dairy because bacteria have already worked on it; it is fattier, softer, less allergenic and less stimulating to the immune system than milk, yogurt and casein-rich fresh products. – Studies contradicting or limiting the claim