Narrative reviewindependent cross-checkabstract only checked I-MEAT-10 standard review
Well-done, high-heat meat contains mutagens
Well-done meat intake, heterocyclic amine exposure, and cancer risk.
Overview
Zheng W et al.. Nutr Cancer 2009 · PMID 19838915 · DOI 10.1080/01635580802710741
Studies suggest higher cancer risk with well-done meat and HCAs.
Does the study support the specific claim? Unclear · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Well-done meat and cancer.
- How was the study done?
Narrative review.
- How many people, animals or samples were studied?
Epidemiological studies.
- What was actually found?
Possible risk increase.
- How large was the observed effect?
n/a
- What do the results mean in everyday life?
Avoid charring/over-frying meat.
- What are the study's limitations?
Narrative.
- What does it say about Elawady's specific claim?
Relevant to frying step.
- Do the results apply to Germany and Europe?
Moderate.
- What can explicitly not be concluded from this study?
Effect of boiling then frying.
Scientific in-depth review
1. Full reference
- Authors
- Zheng W et al.
- Journal
- Nutr Cancer
- Year
- 2009
- Identifier
- PMID 19838915 DOI 10.1080/01635580802710741
- Verification
- verified – PubMed efetch 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
Grants listed in PubMed: NCI NIH HHS
2. Research question
Well-done meat, heterocyclic amines and cancer risk.
3. Study design and population
- Study design
- Narrative review – Narrative review of epidemiological studies on well-done meat and HCA exposure.
- Population
Epidemiological studies
- Country
USA (authors)
- Period
~10 years of studies before 2009
- Sample size
Not stated
- Inclusion and exclusion criteria
Not systematic.
4. Methods and endpoints
- Exposure / intervention
Well-done meat; HCAs
- Comparator
n/a
- Endpoints
Cancer (breast, colorectum, prostate).
- Statistical methods
None.
5. Actual results
- Results
HCAs are potent mutagens in Ames tests and induce tumours in animals; majority of epidemiological studies show high intake of well-done meat and HCA exposure may increase human cancer risk.
- Absolute risks
not reported
- Authors' conclusion
High intake of well-done meat and HCA exposure may increase cancer risk.
6. Strengths
- Overview
7. Weaknesses
- Narrative; exposure assessment of doneness uncertain
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- not assessable
- Rationale
Narrative review.
9. Assessment of the statistical interpretation
None.
10. Relevance to the specific claim
Supports concern about high-temperature frying (C-MEAT-04).
11. Independent contrary findings
I-MEAT-01 Q&A (insufficient data on cooking method).
12. Transferability to Germany and Europe
Moderate.
13. Overall methodological judgement
Plausible but uncertain.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | not assessable |
| Precision of results | not applicable |
| Directness | indirect |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | moderate |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Boil-then-fry sequence.
15. Linked fact checks
- Red meat should first be boiled well and then fried in ghee; this is the recommended cooking method in the system. – Studies supporting the claim