Experts have called a New Zealand study on fish oil supplements fundamentally flawed calling for it to be retracted immediately. They have also called for a public apology to the natural health products industry.

The study from Canterbury University NZ stated that 60 per cent of fish oil supplements didn't contain the advertised amount of omega-3 fatty acids.

A fundamental blunder

But the experts point out that there was a basic error in the calculation of omega-3s in the products.

"The study authors made a fundamental blunder in the calculation of the concentration of omega-3s in the range of capsules studied," said Lorraine Moser Chairperson of Natural Products New Zealand, the national industry organisation representing New Zealand's natural products and complementary medicines.

"Due to the calculation errors, the paper mistakenly concluded that 40% of the products tested for omega-3 fatty acids were accurate and true to label, while five others contained between 48 and 89 per cent of the amount listed. The paper stated that just one of the products contained the amount listed on the label.

“Though, 90% of the products met their label claims. The samples of 10 products were analysed by a reputable independent laboratory, which always conveys its results as the amount per gram.

However, the tested fish oil products were in different capsule sizes – some were 1 gram, others were 1.5 grams and 2 grams.

Not extrapolating the results = flawed results

When the laboratory analysed these capsules (according to its normal testing practices), it stated all findings in terms of the amount of omega-3 per gram.

But, when calculating the quantity of active ingredient in each capsule, the researchers failed to take account of the fact that the test results were in 1-gram units.

Inaccurate results

The results should have been extrapolated for larger capsule sizes. When assessing the label claims for products with 1.5-gram capsules, the researchers did not multiply the test results by 1.5 which would have given an accurate result.

Correctly extrapolating the test results for each capsule size has shown that all but one of the tested products were well within acceptable amounts related to their label claims.

Presenting fiction as fact

Ms Moser says the paper has presented label inaccuracy fiction as fact, needlessly damaging the industry's reputation and concerning consumers.

"New Zealand's natural health products industry has incredibly high standards in terms of product quality and ethical behaviour," said Ms Moser. "Ensuring natural health products are safe, effective and contain what is stated on the label lies at the very heart of what our members and we do. So, it is incredibly frustrating to see shonky research like this not only being published but also publicised," she says.

Australian complementary medicines – the benchmark for the world

Some of the tested products were cited to be of Australian origin.  Carl Gibson, CEO of Complementary Medicines Australia said: “Australian complementary medicines, are produced according to the code of Good Manufacturing Practice and regulated by the Therapeutic Goods Administration (TGA). The TGA sets exceptionally high quality and safety standards, standards that are viewed as the consumer protection benchmark. Consumers can rightly have every confidence in complementary medicines manufactured in Australia.”

A public apology is called for

Natural Health Products NZ wants the NZ Medical Journal to immediately retract the paper, remove it from their website, and issue a media statement to this effect.

A public apology for damage to the industry's local and international reputation – particularly companies that sell fish oil products is also being called for.

Retailers also deserve an apology because it is possible that publicity surrounding the erroneous research will affect their sales.

Media outlets that have covered the initial research have a moral obligation to balance that coverage with the issues raised here, so that consumers are made aware of the research paper's inaccuracies say Natural Health Products NZ.

The body will also be drawing this matter to the University of Canterbury's attention and requesting that it review processes associated with an earlier thesis upon which this paper is based, as well as on the paper itself.

Reference

Are over-the-counter fish oil supplements safe, effective and accurate with labelling? Analysis of 10 New Zealand fish oil supplements”, authored by Julia J Rucklidge, Shelby Hantzand Ian C Shaw.