Cohort studyindependent cross-checkabstract checked I-FAT-103 standard review
Iranian study: ghee not linked to heart events; hydrogenated oil linked to heart attacks
Longitudinal association of dietary fat intake with cardiovascular events in a prospective cohort study in Eastern Mediterranean region.
Overview
Sadeghi M et al.. Int J Food Sci Nutr 2021 · PMID 33719857 · DOI 10.1080/09637486.2021.1895725
No association for ghee; HVO top quartile ~68% more MI (borderline).
Does the study support the specific claim? Partly · Methodological quality: low
Plain-language summary
Study explained simply
- What did the researchers want to find out?
Study fat types and CVD in Iran.
- How was the study done?
Cohort, 13 years.
- How many people, animals or samples were studied?
5432 adults.
- What was actually found?
Ghee not associated; hydrogenated oil possibly harmful.
- How large was the observed effect?
HVO MI HR ~1.68.
- What do the results mean in everyday life?
Hydrogenated (trans) fats are the clearer danger.
- What are the study's limitations?
Low power.
- What does it say about Elawady's specific claim?
Partly supports the claim.
- Do the results apply to Germany and Europe?
Regional.
- What can explicitly not be concluded from this study?
Cannot show ghee is safe.
Scientific in-depth review
1. Full reference
- Authors
- Sadeghi M et al.
- Journal
- Int J Food Sci Nutr
- Year
- 2021
- Identifier
- PMID 33719857 DOI 10.1080/09637486.2021.1895725
- Verification
- verified – PubMed efetch 2026-10-26
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract
2. Research question
Are dietary fat sources (incl. ghee) associated with CVD?
3. Study design and population
- Study design
- Cohort study – Prospective cohort (Isfahan Cohort Study), validated FFQ, 13-year follow-up
- Population
Iranian adults >=35 y
- Country
Iran
- Period
2001-2013
- Sample size
5432
- Inclusion and exclusion criteria
ICS participants
4. Methods and endpoints
- Exposure / intervention
Hydrogenated vegetable oil, non-hydrogenated oil, olive oil, ghee, animal fats
- Comparator
Lowest quartile
- Endpoints
MI, IHD, stroke, all-cause and CVD mortality
- Statistical methods
Multivariable Cox
5. Actual results
- Results
Top v bottom quartile HVO: MI risk 68% higher (95% CI 1.02-2.78; P=0.058). 'No association was found for other dietary fat sources' (including ghee) with ischaemic heart disease, stroke, all-cause and CVD mortality after full adjustment.
- Absolute risks
not reported
- Authors' conclusion
Higher consumption of HVO was associated with increased risk of myocardial infarction.
6. Strengths
- Eastern Mediterranean population
- Ghee measured
- 13-year follow-up
7. Weaknesses
- Frequency-based FFQ
- Modest size; limited power
- CI and P value inconsistent for HVO
- Abstract only
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
Limited power; possible exposure misclassification.
9. Assessment of the statistical interpretation
Null ghee result with limited power is not evidence of safety.
10. Relevance to the specific claim
The most direct regional cohort found no association of ghee with CVD events, which partly supports the claim; the main harm signal was for hydrogenated vegetable oil.
11. Independent contrary findings
I-FAT-101, I-FAT-102, I-FAT-01.
12. Transferability to Germany and Europe
Highly relevant to Egypt (similar fats).
13. Overall methodological judgement
Weak support; absence of association with low power.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | low |
| Risk of bias | some concerns |
| Precision of results | low |
| Directness | direct |
| Reproducibility | unknown |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Larger regional cohorts.