Omega 3 Supplements from New Zealand and Australia: less EPA and DHA than declared

Almost all fish oil supplements produced in New Zealand and Australia contain fewer fatty acids than indicated on the label: only 3 out of 32 contain the Omega 3 corresponding to the stated levels. Furthermore, most products exceed the recommended oxidation level. These findings are prompting authorities to review guidelines on fish oil supplements.

This is revealed by a scientific report published in the journal Nature and conducted by researchers from the University of Auckland (New Zealand).

Fish oil: important health effects

Fish oil supplements are among the most widely used dietary supplements worldwide. They contain significant amounts of polyunsaturated omega-3 fatty acids including EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Fish oil supplements have shown promising effects in reducing inflammation, improving cognitive abilities, and lowering the risk of cardiovascular diseases. Omega-3 fatty acids are highly susceptible to oxidation due to the large number of double bonds in their structure. In a low-quality omega-3 supplement, oxidation replaces omega-3 fatty acids with lipid peroxides and secondary oxidation products. 

The mere addition of antioxidants reduces but does not prevent oxidation. The degree of oxidation can be described by measuring various parameters used to estimate the total oxidation value. Several organizations worldwide have recommended maximum levels for such indices; however, these are based on palatability, as there are no clear data on health effects.

Omega-3 contents lower than those stated on labels

During the study, 32 different brands of supplements, almost all produced in New Zealand and Australia, were analyzed before their expiration date for their Omega-3 content using gas chromatography. Peroxide values and other metabolites were measured to calculate the total oxidation degree. The analyses showed a discrepancy between the EPA and DHA content in the samples and that indicated on the packaging, and highlighted that 92% of supplements exceeded the oxidation product content. According to Ian Musgrave, toxicologist and pharmacologist at the University of Adelaide, this last fact is very important; while a lower-than-expected dose of Omega-3 may not be harmful, oxidation byproducts could be, especially in supplements that greatly exceed international guideline values. 

Excess oxidation products in a supplement are considered contamination and should be addressed by the Therapeutic Goods Administration (TGA), the Australian authority regulating medicines and medical devices, also providing information on regulations and safety. It should be noted that there are currently 683 products containing fish oil registered with the TGA, but also some containing fish oil sold in Australia as foods, and therefore not regulated.

Consumers may take smaller doses than they believe

According to Ken Harvey, drug policy expert and associate professor at the Monash University School of Public Health, the study highlighted long-standing shortcomings in complementary medicine regulation in Australia and New Zealand. These include limited pre-market product evaluations, limited and poorly targeted post-market surveillance, and lack of effective provisions discouraging violations of TGA regulations. 

Numerous reports over the last ten years have highlighted the lack of sanctions for manufacturers who mislead consumers about their products' contents. Those who take fish oil supplements do so to achieve an anti-inflammatory effect or to keep triglyceride levels low, but in reality they may be taking less effective doses, as noted by Peter Clifton, professor at the Baker Heart and Diabetes Institute in Melbourne. Furthermore, this study shows that the high levels of oxidation products may interfere with the benefits of Omega-3s, although long-term implications are unknown. Researchers suggest that highly oxidized fish oil may promote fat deposits in arteries, thus causing the opposite of what consumers expect from supplements.  

Source: Benjamin B. Albert, José G. B. Derraik, David Cameron-Smith, Paul L. Hofman, Sergey Tumanov, Silas G. Villas-Boas, Manohar L. Garg & Wayne S. Cutfield “Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA” Scientific Reports 5, Article number 7928. doi:10.1038/srep07928