Most fish oil supplements sold in New Zealand contain less omega-3 fatty acids than their labels claim, according to new research led by scientists at the University of Auckland’s Liggins Institute.
Analysing 32 brands of fish oil capsules marketed in New Zealand, the researchers found that only three contained the same concentrations of omega-3 fatty acids as listed on the label, and that most products contained less than two thirds than the amount stated.
The scientists also measured at the level of oxidation in fish oil products, as omega-3 fatty acids are unstable and can breakdown over time. They found that over half had oxidised to a level higher than the recommended limit. Surprisingly, this was not linked to the ‘best before’ date, price, or country of origin.
The research was published in the journal Scientific Reports this week.
The Science Media Centre contacted New Zealand experts for comment on the study and its findings. Feel free to use these quotes in your reporting. If you would like to contact a New Zealand expert, please contact the SMC (04 499 5476; firstname.lastname@example.org).
NEW COMMENT: Dr Laurence Eyres, from the Oils & Fats Specialist Group of the New Zealand Institute of Chemistry, FNZIFST, comments:
“A group of NZ researchers (not professional analysts) from the University of Auckland recently investigated both % fatty acid composition and oxidation levels of off-the-shelf fish oil supplements. Selected fish oil supplements were not identified by brand owner. The results were skewed very negative- both on label claim compliance and oxidation levels. The attached study came out into the public recently and generated negative publicity for the industry, both in New Zealand and in Australia
“The omega-3 centre has had several Omega-3 and lipid experts take a look at the results and they were surprised; both for the non-compliant results on oil % analysis for EPA/DHA and for the out-of-spec oxidation levels. In Australia, CSIRO did similar research in 2014 on % EPA/DHA and the results were predominantly compliant. Consumer Lab in the USA did a similar study and most brands were compliant; Consumer NZ did a survey in 2007, the results were not as negative as this one.
“This study highlights an issue I have seen in the industry and academia for years, which is around consistent testing methods across the commercial and research laboratories in this region of the world. The AAOCS committee strongly recommends the Global Organization for EPA and DHA Omega-3 (GOED) nutraceutical oils proficiency program run by the AOCS. This program tests both fatty acids composition but also quality , oils by acid value AV ,oxidation ( (), peroxide value (PV), para- anisidine value (p-AV) and TOTOX (summation of oxidation by the formula 2 x PV + pAV)).This program uses AOCS methods and is in line with GOED Voluntary Monograph quality standard for EPA and DHA oils. The reported paper did not use validated methods and they were not certified by a proficiency programme.”
Dr Eyres is a consultant to the food industry
Prof Murray Skeaff, Professor in Human Nutrition at the University of Otago, comments:
“If the results are accurate, then fish oil supplements in New Zealand can be added to a long list of dietary supplements for which there are serious discrepancies between what the manufacturer claims the consumer is getting and what is actually in the supplements.
“Of additional concern is that the vast majority of the fish oil supplements contain amounts of oxidised fats that exceed recommended levels, in other words the oils are on the road to becoming rancid if not already so.
“The researchers should publish the brand names of the fish oils supplements that were analysed so that consumers may be able to identify the supplements of highest quality.”
Dr Matt Miller, Marine lipid chemist at Plant & Food Research and President of the Australasian section of the American Oil Chemist Society (AAOCS), comments:
“The results of the study on fish oil supplements available in New Zealand are troubling but are not surprising as there have been other comparable studies conducted around the world with similar results. However, there is still an overwhelming body of scientific evidence about the nutritional benefits of omega 3 supplementation. It is well understood that omega 3 is a very bioactive compound and the double edged sword is that it is prone to oxidative degradation.
“The high levels of oxidation shown in some products are indicative of the long journey the oil has to take to get to the pharmacy. As indicated in the article most of the fish oil available in New Zealand, whether capsulated here or in another country, comes from the anchovy/sardine fishery off the coast of Peru. After catch, it is rendered, sometimes refined and sent by ship around the world where it is then refined and capsulated by local companies. Although care is taken, this long journey from ocean to consumer provides ample opportunity for oxidation, a degradative chain reaction, to occur.
“As discussed in the report, it is uncertain whether the level of oxidation in the study poses a health risk, however, for the consumer the best advice is to protect their fish oil by storing it sealed in the fridge and out of direct light.
“This study demonstrates the opportunity here in New Zealand to produce quality marine oils for the local market from our own fishing industry catch. Plant & Food Research is working with several New Zealand companies, such as Seadragon Marine Oils and the Sealord Group Ltd, to investigate the potential for NZ industry to supply high quality marine oil products.”
Declared interests: Plant and Food Research works with Seadragon Marine oils and other major fish companies trying to produce NZ based oils. Plant and Food Research does not work presently with any companies that make fish oil capsules.
Comment collected from our colleagues at AusSMC:
Professor Peter Clifton, Head of the Nutritional Interventions Laboratory at Baker IDI Heart and Diabetes Institute and Professor of Nutrition at the University of South Australia, comments:
“This is very useful, interesting and important information. Clearly the bulk fish oil producers have been deceiving the public and the encapsulators about the EPA and DHA content of their oil and the ACCC and the Therapeutic Goods Administration need to get involved.
“For those members of the public trying to get an anti-inflammatory or triglyceride lowering effect from fish oil the reason the oil may not be working for them may be under-dosing, despite taking the recommended number of capsules. Similarly, the high oxidation products may be interfering with how well the pills work but we really don’t know the long term implications of high oxidation products.
“As the paper points out it is possible very oxidised fish oil may promote the formation of fatty deposits in the arteries and thus the opposite of what the consumer is expecting, and may even account for some of the recent negative clinical trials if the EPA and DHA were significantly oxidised. No comment was made in any of the recent papers about oxidation levels although the fish oil amounts were quantified.”