Omega-3 capsule concentration is mostly mislabelled, say researchers

Researchers from Auckland University’s Liggins Instate carried out detailed analysis of EPA and DHA content and degree of oxidation of fish oil capsules marketed in the country. They expressed their doubt about the concentration of these acids, and the general stability of omega 3, which could cause unknown effects, they said.

Three out of 32 deemed accurate​

Their results showed that only three of the 32 products tested contained the concentrations listed on the label. In over half of the products, the oil had oxidised to a level higher than the recommended limit, meaning the oil was turning rancid or already off.

They also found these measures were unrelated to “best-before” date, price or country of origin.

The researchers used validated chemical methods to analyse concentrations of EPA, DHA and recognised oxidation markers for all fish oil capsules available in New Zealand. Analyses and results were standardised to allow valid comparisons across all products.

Details of the study have been published in the journal Scientific Reports​: Albert, BB et al. “Fish oil supplements in New Zealand are highly oxidised and do not meet label content of n-3 PUFA”​. Sci. Rep.​ 5, 7928; DOI:10.1038/srep07928 (2015).

“The very similar composition data listed on product labels could reflect reliance on data from companies that extract and supply raw fish oil product to individual brands and do not take into account effects of transport, encapsulation, packing, storage and seasonal variation​,” the researchers learnt.

No danger, but more regulation needed​

Research leader Professor Wayne Cutfield, the Liggins Institute Director and one of the research authors, emphasised that this does not mean the products are dangerous, but it suggests that tougher regulations should be applied to determine the product actual compounds and whether it is degraded, or may imply a potential health risk.

“Future studies should investigate how different storage conditions affect the oxidation process. Importantly, they should take into account the effects of typical retail and home storage conditions on the rate of n-3 PUFA oxidation,” he said.​

“In addition, any reports of the physiologic or metabolic effects of fish oil capsules should include measured levels of the main oxidation products so we can better understand how oxidation impacts upon the effectiveness of the supplements and whether there are any harmful side effects.”​

New Zealand is now discussing the Natural Health and Supplementary Products Bill, which aims at regulating the manufacturing and selling of natural health products. This initiative also seeks to provide the right to information about these products and their functions, and the right to use products that are safe and effective.