Study finds fish oils are oxidised and do not contain claimed EPA/DHA content: Do you really know what you taking?

A massive 92% of fish oils did not meet the Global Organisation for EPA and DHA (GOED) international standards in a New Zealand study released in January 2015. Researchers tested fish oils found both online and in retail outlets and found the fish oils to be highly oxidised and not meeting label claims for omega-3 content, two of which were practitioner-only fish oils. The study also found a large disparity between label claims of EPA and DHA content and actual content.  Only three of the 32 oils tested for EPA/DHA content contained the amount stated on the label, with more than two thirds containing less than 67% of the stated content.  Two of these fish oil supplements contained just one third of the label concentration of EPA and DHA.

Whilst this research made headlines earlier this year, the GOED has queried the study methodology and the handling of samples. Yet this research has highlighted the urgent need for transparency on testing results among companies providing fish oils to practitioners and patients. Two months later, little action has taken place by companies in improving transparency and providing the evidence to assure practitioners and patients of the quality, purity and freshness of their omega-3 products.

With fish oils being one of the most universally prescribed and self-prescribed nutrients it is not surprising that this research has created a great deal of confusion and consternation amongst practitioners and patients alike. How can this happen? Does this mean I am consuming rancid fish oil? What is actually in my fish oils? How does this impact my clinic and patients?

Something fishy…?

One way to overcome this confusion and to assure that processing, packaging, encapsulation and storage has not interfered with the quality of the omega-3 is by utilising independent third party testing. It’s interesting to note that most fish oil companies often disclose evidence of manufacturer testing but not independent third party testing. One could ask, why is that?

Manufacturer testing measures the purity and freshness of the fish oil before encapsulation whereas, independent third party testing verifies the quality, content and freshness of the lipids after encapsulation. Whilst both manufacturer and third party testings measure heavy metals, environmental toxins and pollutants it is the EPA/DHA content, freshness and oxidation levels that are of critical importance, especially after encapsulation

Marine omega-3 oils are highly susceptible to degradation and oxidation if handled improperly during manufacturing, storage or encapsulation processes; it is therefore essential to test and quantify the levels of oxidation markers and bioactive lipids, bothbefore and after encapsulation to verify the quality, freshness and strength of the lipids within each capsule.


What do I look out for to make sure my fish oils are fresh?

While specific oxidation species are difficult to measure, the degree of oxidation can be described by measuring the peroxide value (PV) and the anisidine value (AV). PV reflects the primary oxidation products (lipid peroxides) while AV reflects secondary oxidation products (aldehydes and ketones). Together, these parameters are used to estimate the total oxidation value (TOTOX). 

This research, published in January, measured omega-3 content and oxidation markers – peroxide, anisidine and total oxidation (TOTOX).  The results were staggering – 83% of products exceeded the recommended peroxide level50% exceeded recommended TOTOX thresholds and 25% surpassed anisidine values.  Interestingly, they also found two practitioner-only fish oils had excess oxidation.  The peroxide value on the labels of one of these products exceeded the claimed amount four-fold.  

So what is the “take home” message from this research?
This study has highlighted the need for independent third party testing to ensure manufacturer’s claims are verified after processing and encapsulation and the need for transparency of these results. It’s imperative that the exceptional standards are upheld and the appropriate respect is attributed in the processing of marine omega-3 oils to maintain exceptional quality, purity and freshness.

What can I do to ensure the highest quality for my patients?

Viewing the evidence of independent third-party testing can confirm fish oil purity claims and give the quality assurance and peace of mind that practitioners and their patients expect. Nutrasource Diagnostics is the world’s leading third party testing body conducts the International Fish Oil Standards Program (IFOS) for omega-3 which sets the highest standards for safety, purity and quality. Nutrasource also utilises True Anisidine Value (TAV) Test a method uses High Performance Liquid Chromatography (HPLC) and distinguishes lipid oxidation from flavours, antioxidants and vitamins.  Conventional testing can return false positives for rancidity in flavoured fish oils.

Independent Third-party testing Checklist:

✔ IFOS 5-star rating

✔ True EPA/DHA content

✔ Radiation Testing

✔ Environmental Pollutants

✔ Heavy Metals Pesticides

 True Anisidine Value for Oxidation


Albert, B, Derraik, J, Cameron-Smith, D, Hofman, P, Tumanov, S, Villas-Boas, S, Garg, M & Cutfield, W  2015, ‘Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA’, Scientific Reports, doi:10.1038/srep07928.

 Source: Bioconcepts

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