Measurement / residue studyindependent cross-checkabstract only checked★ key study I-FSH-02 in-depth review
Wild vs farmed Atlantic salmon (Norway 2017)
Lower levels of Persistent Organic Pollutants, metals and the marine omega 3-fatty acid DHA in farmed compared to wild Atlantic salmon (Salmo salar).
Overview
Lundebye AK et al.. Environ Res 2017 · PMID 28189073 · DOI 10.1016/j.envres.2017.01.026
Wild salmon had more dioxins, PCBs and mercury than farmed salmon; both were good omega-3 sources.
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?
Compare same species.
- How was the study done?
Chemical analysis.
- How many people, animals or samples were studied?
Wild and farmed Atlantic salmon.
- What was actually found?
Farmed lower in most contaminants.
- How large was the observed effect?
3.2 g vs 2.8 g EPA+DHA per 200 g.
- What do the results mean in everyday life?
Farmed salmon is not more polluted.
- What are the study's limitations?
Details not in abstract.
- What does it say about Elawady's specific claim?
Contradicts 'farmed is more polluted'.
- Do the results apply to Germany and Europe?
High.
- What can explicitly not be concluded from this study?
Other farmed species.
Scientific in-depth review
1. Full reference
- Authors
- Lundebye AK et al.
- Journal
- Environ Res
- Year
- 2017
- Identifier
- PMID 28189073 DOI 10.1016/j.envres.2017.01.026
- Verification
- verified – PubMed efetch 2026-10-25
- Retracted
- no
- Corrections
- none
- Extent checked
- abstract only
- Conflicts of interest and funding
not stated in abstract/record
2. Research question
Do contaminants and fatty acids differ between wild and farmed Atlantic salmon (same species)?
3. Study design and population
- Study design
- Measurement / residue study – Comparative measurement of POPs, metals and fatty acids in wild and farmed Atlantic salmon
- Population
Wild and farmed Atlantic salmon
- Country
Norway
- Period
published 2017
- Sample size
not stated in abstract
4. Methods and endpoints
- Exposure / intervention
Farmed vs wild
- Comparator
Wild Atlantic salmon
- Endpoints
Dioxins, PCBs, PBDEs, OCPs, metals, fatty acids
- Statistical methods
Group comparisons
5. Actual results
- Results
Dioxins, PCBs, OCPs and mercury higher in wild than farmed; PBDE, cadmium, lead low and comparable; DHA higher in wild, EPA not different; total fat and omega-6 higher in farmed; n-3:n-6 lower in farmed; contaminants 'well below maximum levels applicable in the European Union'; 200 g/week gives 3.2 g (farmed) or 2.8 g (wild) EPA+DHA.
- Absolute risks
not reported
- Authors' conclusion
Both farmed and wild Atlantic salmon are good sources of EPA and DHA.
6. Strengths
- Same-species comparison
- EU limits referenced
7. Weaknesses
- Norwegian government institute authors (no COI stated)
- Sample size not in abstract
8. Risk of bias
- Orienting tool
- none applicable
- Type of assessment
- simplified assessment (abstract only)
- Full formal assessment
- no
- Overall risk of bias
- some concerns
- Rationale
Sampling details not in abstract.
9. Assessment of the statistical interpretation
10. Relevance to the specific claim
Key counter-evidence to C-FSH-01/02/05/13; supports C-FSH-04.
11. Independent contrary findings
Older studies A-FSH-01 (different species, 2002).
12. Transferability to Germany and Europe
High.
13. Overall methodological judgement
Most EU-relevant comparison read.
| Multidimensional assessment | |
|---|---|
| Authenticity of the source | verified |
| Methodological quality | moderate |
| Risk of bias | some concerns |
| Precision of results | moderate |
| Directness | direct |
| Reproducibility | partly replicated |
| Consistency with the overall evidence | mixed |
| Regional transferability | high |
| Adequacy of the interpretation (by the archive) | not applicable |
14. Open questions
Representativeness of wild sample.
15. Linked fact checks
- Farmed salmon contain significantly higher concentrations of organochlorine contaminants (PCBs, dioxins, chlorinated pesticides) and PBDE flame retardants than wild salmon, and European-farmed salmon carry the highest loads (based on samples analysed by Hites et al. around 2002). – Studies contradicting or limiting the claim
- Farmed fish today accumulate PCBs, dioxins and PBDEs at concentrations significantly higher than in their wild counterparts (present-tense generalisation in the archive summary). – Studies contradicting or limiting the claim
- Farmed Atlantic salmon from northern Europe should be eaten no more than once every five months to stay below an acceptable cancer-risk threshold (and, per the archive's card for Foran 2005, dioxin-contaminated farmed salmon less than once a month). – Studies contradicting or limiting the claim
- The omega-3 to omega-6 ratio is about 10 in wild salmon but only 3-4 in farmed salmon. – Studies supporting the claim
- Because of the lower omega-3:omega-6 ratio, farmed salmon is converted from an anti-inflammatory into a pro-inflammatory meal, and the expected nutritional benefit disappears. – Studies contradicting or limiting the claim
- All salmon is farmed and salmon should not be eaten; sea bass, sea bream and similar fish should be eaten instead. – Studies contradicting or limiting the claim
- Natural wild sea fish is the cleanest food you can get; wild sea fish (including large predators such as grouper/hamour, tuna, and smoked mackerel) is allowed while farmed fish is forbidden. – Studies contradicting or limiting the claim