The risk of pollutants from oily fish, such a methyl mercury, dioxins, and polychlorinated biphenols (PCBs) have led to some claims to reduce fresh fish intake, especially for pregnant women who may damage the development of their babies.
Such advice has seen the number of omega-3 enriched or fortified products on the market increase. Most extracted fish oil are molecularly distilled and steam deodorised to remove contaminants.
According to Frost and Sullivan, the European omega-3 market was worth around €160m (£108m) in 2004, and is expected to grow at rates of 8 per cent on average to 2010.
The British Food Standards Association (FSA) reported last week that while pollutants in fish eaten in the UK are continuing to fall, 70 per cent of the British population do not eat any fish at all during the week.
"The results of these surveys are good news. We don't eat enough fish in Britain and we should be eating more," stated Andrew Wadge, the FSA's director of food safety.
"Eating fish is a good way to get protein and some essential vitamins and minerals, and oily fish, for example salmon, sardines and mackerel, also give added protection against heart disease."
At the recent annual meeting of the American Association for the Advancement of Science, a panel of experts said that the benefits of eating seafood continue to outweigh the risks.
"The best science coming out over the last two years has overwhelmingly been in favour of the benefits of seafood consumption," said Michael Morrissey from Oregon State University's Seafood Laboratory.
Phillip Spiller, director of the Office of Seafood for the US FDA, said: "We must formulate a clear message for the consumer."
During the meeting, Phil Davidson from the University of Rochester Medical School, reported that a ten-year study of over 700 children in the Seychelles Islands, where women average 12 meals of fish a week, showed no cognitive defects that can normally be seen from mercury absorption.
Morrissey responded that the results were fascinating: "Is there something beneficial in consuming the fish that negates any adverse effects of the mercury? The science isn't quite there yet. But it underscores the importance of looking at the issues holistically instead of formulating conclusions based on scattered evidence."
Morrissey stressed that pregnant women should stick with current FDA recommendations of about 12 ounces (340 grams) per week. The rest of the population should be eating fish four to seven times per week.
Steve Otwell from the University of Florida warned however that, on a world scale, there may be shortfall of fish of up to 10m metric tons by 2010.
This could be filled by supplement makers, some of whom use vegetable sources like walnuts and canola oil for their omega-3. However there is evidence to suggest that the vegetable-derived omega-3 has much less bioavialability for the human body.
The omega-3 fatty acids that have received the most attention are eicosapentaenoic acid (EPA) and docosahexaenioc acid (DHA).
EPA is proposed to function by increasing blood flow in the body. It is also suggested to affect hormones and the immune system, both of which have a direct effect on brain function.
DHA, on the other hand, is involved in the membrane of ion channels in the brain, making it easier for them to change shape and transit electrical signals.
Omega-3 supplementation of products has been a major growth area in the neutraceutical market. Mintel's Global New Products Database (GNPD) showed a 36 per cent increase in omega-3-containing product launches across Europe in 2005.