A study that suggested that consumers began to briefly change fish oil supplements was withdrawn.
A study, recently published in the New Zealand Medical Journal, but this week downloaded the top 10 most popular products available in New Zealand.
It indicated that less than half contained the same amount of omega-3 fatty acids (EPA and DHA) listed on the packaging, while the rest contained between 48 and 89 percent.
The group representing the natural health products industry quickly questioned the results and questioned the methodology used in the study.
Researchers at the University of Canterbury who conducted the study asked to withdraw this document.
In a statement, they said they made mistakes in calculating the amounts of EPA and DHA in five fish oil supplement capsules, "which means we underestimated the doses."
"They are all within 15 percent of the label value. This, in turn, affects our assessment of compliance with health claims; however, they remain variable. "
Herald understands that the journal will publish the withdrawal in the next edition.
Natural Health Products NZ (NHPNZ) questioned the error of the study because the fish oil products tested had different capsule sizes.
Some capsules had 1 gram, some 1.5 grams, and others 2 grams.
When the laboratory analyzed the capsules, according to their normal test practices, it reported all results in terms of omega-3 per gram.
NHPNZ argued that when calculating the amount of active ingredient in each capsule, the researchers did not take into account the fact that the test results were in units of one gram, so it was necessary to extrapolate for larger capsule sizes.
"When assessing label claims for products containing 1.5 grams of capsules, scientists did not multiply the test results by 1.5 to get an accurate result," the group said.
"Correct extrapolation of test results for each capsule size showed that all but one of the products tested were within the tolerance limits associated with their label statements."
Group chairman Lorraine Moser said the newspaper presented "fiction about inaccuracies in advertising as a fact, unnecessarily damaging the industry's reputation and unnecessarily giving consumers concern."
The group also claims other flaws in the document.
The study was not the first to question the content of fish oil supplements.
Four years ago, scientists from the University of Auckland & # 39; s Liggins Institute tested 36 brands and found that only three contained the same concentrations of omega-3 fatty acids as stated on the label.
Their analysis showed that the products contained on average only 68 percent of the declared content – and more than two-thirds of the tested supplements contained less than 67 percent.
Two products contained only a third of what was on the label.
Since then, an international systematic review, based on nearly 80 randomized studies involving over 100,000 people, suggested that long-chain omega-3 supplements, such as fish oil, did little to protect against a heart attack or stroke.
Positive results have also been reported, and researchers from Liggins have also shown that fresh fish oil can prevent the development of diabetes in overweight children.
• The original Herald article on the study was modified to reflect withdrawal.