The Study
Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA
This study checked a bunch of fish oil pills in New Zealand and found that many didn't have as much healthy oil as they said on the label, and some were already spoiled. But it didn't test if these pills made people sick or helped them feel better—it just looked at what was inside the bottles.
Analysis score
Maximum 44 for a cross-sectional study.
Where the score came from
Scientists tested fish oil pills sold in New Zealand to see if they had the omega-3s they claimed and if they were fresh.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 525 / 100
Quality score
Snapshots of a population at a single point in time, or descriptions of small groups. Can identify correlations and prevalence, but cannot determine cause and effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1This means most people taking these pills aren't getting the health benefits they expect, and they can't tell by price or expiration date.
- 2Only 9% had the full amount of omega-3s they promised.
- 383% were so old or damaged they had too much rancidity.
- 4Even expensive or late-expiry pills weren't better.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Scientific Reports
Year
2015
Authors
B. Albert, J. Derraik, D. Cameron-Smith, P. Hofman, S. Tumanov, S. Villas-Bôas, M. Garg, W. Cutfield
Related Content
Videos (2)
Claims (7)
Fish oil supplements with higher concentrations of EPA and DHA tend to cost more, but paying more does not guarantee the product is less oxidized or more stable once you account for the actual EPA and DHA content.
A sample of 36 fish oil supplements sold in New Zealand was tested for freshness, and most showed signs of oxidation, meaning they had degraded beyond accepted quality standards.
A study found that most fish oil supplements sold in New Zealand contained significantly less of the key omega-3 fatty acids (EPA and DHA) than stated on their labels, with only a small number meeting their advertised content.
How long a fish oil supplement has until its best-before date does not predict how much it has oxidized. This means the date on the label may not indicate whether the product is still fresh.
Fish oil supplements from countries other than New Zealand or Australia cost more but contain the same amounts of EPA and DHA and show similar levels of oxidation, meaning where they are made does not determine how good they are.
Fish oil supplements that have degraded due to oxidation tend to have less EPA and DHA than what is listed on the label, which may explain why some products contain lower amounts than claimed, though other factors can also cause this discrepancy.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.