What is oily fish?
When it comes to healthy seafood, the term ‘oily fish’ comes up a lot. But what is it? And why does it matter?
In contrast to ‘white fish’ such as hake, monkfish, haddock, and plaice which all hold fat in their liver, oily fish species contain much higher levels of oils in the flesh itself. This means that when we eat oily fish, we eat the oils too. This is important because these particular oils - long chain omega 3 fatty acids to be specific - cannot be made by our bodies, and they are crucial for health.
The best known oily fish are salmon, trout, mackerel, anchovies, sardines and herring, and the good news is that they are completely delicious too. Fish really is the original fast food - our pan-ready fillets cook in minutes and we have plenty of sauces to complement them, making eating oily fish very easy indeed.
But back to those oils and why they are so good for us. To understand the story better, the best place to start is about 40,000 years ago, and a look at human evolution. It is around this time that early man extended his hunting skills, and we started eating fish and shellfish. It may have been through taking advantage of changing tides exposing bivalves as waters receded each day, or perhaps through spear fishing, but either way, seafood found its way into our diet.
Many scientists see it as no coincidence that the modern human brain - the neocortex - evolved at around the same time. This is the part that helps us process mind boggling amounts of environmental information, deal with complex social interactions, and ultimately allowed for the development of tool-making, language and abstract thought that characterises us as a species. The scientific concept is that suddenly getting access to the powerhouses of nutrition in seafood is what helped man make the leap from great ape to human. It’s the long-chain omega 3 fatty acids that are so special.
Fatty acids, in the form of omega-3s, are crucial to the development and healthy function of our brains, not surprising given that the modern human brain is an astonishing 60% fat.
As if that’s not enough, according to numerous scientific research papers, omega-3s also:
Reduce the risk of certain types of cancers including breast, prostate and colon cancer Reduce anxiety and depression Improve eye health and reduce the risk of macular degeneration Reduce the risk of Alzheimer's Disease Protect us against heart disease by improving cholesterol and blood pressure levels May protect joints and prevent rheumatoid arthritis, thanks to their anti-inflammatory properties
NHS guidance is that we should have one portion of oily fish a week, and the brilliant thing is we’ve made it wonderfully easy for you. It’s also important to clock that along with all those oils comes the clusters of micronutrients present in many seafoods, such as iodine, iron, zinc, copper and selenium.
While fresh tuna is an oily fish, it isn’t once tinned as all those lovely long chain omega 3s are lost in the canning process. That’s just as well, as we need to avoid tuna anyway, and we refuse to sell it. The damaging and controversial tuna fishing practices combined with critical species population numbers in some areas are such that it really is a NOT FOR SALE fish on our red list.
So that’s oily fish. It really is amazing. So what are you waiting for?!