Hardly a week goes by without a new health claim being made of eating oily fish. But is it really as magical as we are told?
If there were a top 40 of good foods, a chart rundown of the right things to eat, then anything containing omega-3 fatty acids would have been number one for years. They even have their own international awareness day, which takes place this Wednesday.
Omega-3 is the name given to a family of unsaturated fatty acids found mainly in oily fish, such as salmon, herring, sardines and anchovies, and also in eggs, meat, milk and cheese.
Oily fish 'can halt eye disease'
The naturally occurring acids of the omega-3 family can apparently boost our brain power, keep our hearts healthy, strengthen our bones, and much more. You can ingest the fatty acids by eating a lot of the right kind of fish or by taking fish oil supplements - little golden capsules rich in omega-3.
Hardly a week goes by without yet another media report on "The wonders of omega-3 fatty acids" (as a headline in Canada put it recently).
Last month it was reported omega-3 can protect against psychotic disorders such a schizophrenia. An international team of researchers gave a daily dose to 81 people deemed to be at risk from psychosis and found it seemed to cut the rate of psychotic illness - including schizophrenia - by 25%.
But how much of this is hype, and how much reality? Is there a danger that a largely fish-derived fatty acid is being turned into a modern-day magic potion?
Dietician Evelyn Tribole is a firm believer in their potency.
Packaging tag
"While it can seem that omega-3s do everything but wash your windows, it's important to remember that they are essential nutrients", says Ms Tribole, author of The Ultimate Omega-3 Diet: Maximise the Power of Omega-3s to Supercharge Your Health, Battle Inflammation, and Keep Your Mind Sharp.
Cattle grazing
Grass-grazing cattle have more omega-3, says Evelyn Tribole
She says modern forms of food production are reducing the amount of omega-3 in our foods, "contributing to a global omega-3 fat deficiency in the diets of most people".
"For example, animals that graze on grass have higher omega-3 contents in their meat - and the longer they are out to pasture, the more omega-3s accumulate in their meat. But today the great majority of animals dine on [corn grain], which is devoid of omega-3s."
That is bad, she says, because "remarkable and consistent" scientific studies show us omega-3 is good for brain function, mood disorders, heart health and more. And she dismisses the claim that this is just a fad.
"Yes, food and nutrition seem to run in fashionable trends, with followers and believers. In this case, however, there is a lot of good evidence for the benefits of omega-3s."
But others are sceptical.
Dr Lee Hooper, lead author of one of the most thorough studies on the apparent benefits of omega-3, published in the British Medical Journal in 2006, urges people not to get "carried away".
The interest in omega-3 has snowballed over the past decade, giving rise to more and more scientific studies, books about how omega-3 can make you super-healthy, and government- and corporate-funded omega-3 promotion groups, such as the Omega-3 International Awareness Day and The Omega-3 Group in Scotland.
