Canterbury University researchers are being challenged to name fish oil products they evaluated

They independently tested 10 supplements, and published the results in the New Zealand Medical Journal.

Only one's contents matched its labelling - and less than half had the listed omega-3 fatty acid content.

Dan King from About Health says we don't know which products they tested, which tars the whole industry.

He says if they believe in their findings, the researchers should name and shame the companies, and stand by the consequences.