Not only is it good for the heart, but oily fish in the diet can improve concentration and have a calming effect, writes Helen Stiles.

It's been reported that there has been an 80% decline in the average intake of Omega-3 in our diet over the last century. Why should this be of concern? You may have considered taking Omega-3 supplements because you've heard it's good for the heart, which indeed it is, it can reduce your risk of heart attack by 30-60%. However, this essential fatty acid is far more crucial to our wellbeing and because it cannot be made by the human body it must be obtained from your food choices or from a daily supplement. Omega-3 is a type of polyunsaturated fat, one of the good fats. Seafood is without doubt the best source of what is known as Omega-3 long-chain fatty acids. This long-chain version contains DHA (docosahexeanoic acid), one of the major building blocks for the brain. The brain is a very fatty organ and nearly half of that fat is made up of DHA. Recent research has shown that having a regular input of this particular Omega-3 can help in the treatment of dyslexia, schizophrenia, depression and anti-social behaviour. Professor John Stein, brother of celebrity chef Rick who has done so much to put fish back on the British menu, is Professor of Neurophysiology at Oxford and Chair of the Dyslexia Research Trust. He has been exploring the impact of fish oils on behaviour and dyslexia for many years and believes that we need fish oils to make the brain work properly. "Fatty acids found in Omega-3 fish oils help improve the function of nerve cells in the brain which deal with visual and social signals. When you don't have them it means you can react badly in an impulsive or aggressive manner." Trials in which oily fish or Omega-3 supplements were added to the diets of young offenders in Scotland saw dramatic improvements in their behaviour. Now Omega-3 has been taken into the classroom. Trials carried out in deprived areas of County Durham using daily doses of liquid fish-oil supplements saw improvement in concentration levels from toddlers through to teenagers. Eight- and nine-year-olds at a primary school in Bradford also took part in trials and showed substantial improvements in reading, writing and maths. It's also been shown to help pupils who find it hard to focus on their studies. So, try increasing your dissolute teenager's intake of Omega-3 leading up to exam time!Our 21st-century diet with its heavy reliance on convenience meals simply doesn't contain the types of food that once provided that weekly hit of Omega-3. Sardines on toast, kippers for breakfast or fish with bones doesn't suit the modern child's palate, and the cod liver oil dished out to mums and children during the war had all but died out by the 1950s. This has left subsequent generations severely lacking in Omega-3, so it's incredibly important that we address this deficit with our food choices.Vegetarians will find sources of Omega-3 in soya, hemp, flax and pumpkin seeds and oils, walnuts and leafy green veggies. However, this plant-based Omega-3 is known as short-chain Omega-3, which has to be converted by the body into long-chain Omega-3's. You can also find Omega-3, which is odourless and tasteless, added to products such as spreads, yoghurts, milk and juice. If all else fails take a good daily supplement of Omega-3 in capsule or liquid form. The richest and most delicious source is found in oily fish such as mackerel, sardines, sprats and salmon �- there is a lovely and very quick recipe for Mackerel Tagine on page 66 If you're not a fishy fish fan, then shellfish also packs a powerful Omega-3 punch and is low in fat and high in protein. Oysters, mussels and brown meat from crab contain as much Omega-3 gram for gram as oily fish. Working a couple of portions, of oily fish a week into your diet will pay dividends for your head and your heart. So, when those old wives said 'fish makes you brainy', they were certainly onto something;