Fish oil sold in NZ is actually more like snake oil

FISHY: A University of Auckland study has found the bulk of fish oil pills sold in NZ are misleading consumers. The take ...
Danielle Smith

FISHY: A University of Auckland study has found the bulk of fish oil pills sold in NZ are misleading consumers. The take home? Just eat fish.

The bulk of fish oil supplements sold in New Zealand and Australia are misleading consumers with false claims, a study has found.

A University of Auckland study found the bulk of supplements sold in  the two countries were almost a third lower in omega-3 fatty acids than their labels claimed.

Only three of the 32 fish oil supplements analysed by the scientists contained the concentrations of fatty acids listed on the label.

The rest had on average 68 per cent of the claimed content.

The University of Auckland's Professor Wayne Cutfield said the research team found the price of each supplement made no difference to the quality of the product.

"You might think that a more expensive fish oil is less likely to be degraded," he said.

"That is not the case, there is no relationship with price."

Although the researchers did not publish the brand names of the fish oil supplements that were analysed, Cutfield said almost half were encapsulated, labelled and marketed from Australia.

Most fish oil products are sourced from deep sea fish from the west coast of South America.

The researchers found the majority of the supplements tested were considerably oxidised —  the oils were on the way to becoming rancid.

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The active ingredients in omega-3 were fragile and prone to oxidisation, which could occur on the long trip from South America, Cutfield said.

"Exposure to light, air and increasing temperatures above freezing, increases the likelihood that they will degrade and become oxidised," he said.

The effects on humans of long-term exposure to oxidised oils had not been studied, he told AAP.

Fish oils are among the most popular dietary supplements in the  world, linked to helping prevent everything from cardiovascular disease to mental illness.

It has been suggested oxidised fish oil might promote the formation of fatty deposits in the arteries and thus achieve the opposite of what the consumer expected.

Cutfield advised consumers to protect their fish oil by storing it sealed in the fridge and out of direct light.

Those who want to ensure good levels of omega-3 should simply eat fish, he said.


The body representing the natural product industry is surprised by the latest study into fish oils sold in New Zealand, because it says most natural products made here are checked and audited.

That said, there is no current manufacturing standard in New Zealand that binds them to such checks. And the sooner that's addressed, the more confident consumers can be, says Natural Products NZ (NPNZ).

Executive director Alison Quesnel says the latest findings highlight the need for regulating the manufacturing and selling of natural supplements in New Zealand. The long-awaited Natural Health and Supplementary Products Bill will strengthen regulation around ingredient and benefit claims and the sort of product information provided.

Quesnel insists though that most New Zealand manufacturers already adhere to Good Manufacturing Practices (GMP) that are audited by the Therapeutic Goods Agency in Australia and the Ministry of Primary Industries in New Zealand.

The TGA regulates any product that is sold in Australia, which applies to a host of New Zealand-made natural products exported across the Tasman.

"So those factories, in order to send products to Australia, have to have an Australian audit but they also have an MPI audit," says Quesnel.

She says most other New Zealand manufacturers are voluntarily adhering to manufacturing audits, even if they're not required to.

"The Bill coming in will raise the bar because it will provide definite manufacturing standards and provide consumers with greater comfort and certainty," says Quesnel. "We are 100 per cent behind a Bill that will standardise things."

Quesnel is surprised by the findings as the "benefits of fish oil are renowned". But the group cannot comment on the results until it has more information and seen the testing methods.


Meanwhile, the Ministry for Primary Industries (MPI) and Medsafe (a business unit of Ministry of Health) are investigating the findings.

A spokesman said MPI and Medsafe had received a copy of the report released by the Liggins Institute. 

Both agencies were following up with the institute to get more information on data used in the study. 

"MPI is working closely with Medsafe on the requirements of the Dietary Supplements Regulations 1985 and how they apply to these products," the spokesman said.

Omega 3 fatty acids were part of a balanced diet and were good for heart health, and foods such as fish were an excellent source of omega 3 fatty acids.

- AAP &


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