Omega-3 fats are essential for every cell in our body and are particularly important for the health of our head and heart. Yet most of us should be eating more. Among other things, they provide the building blocks for hormones that regulate blood clotting, the contraction and relaxation of the artery walls, and control inflammation. Omega-3s are polyunsaturated fats found in oily fish such as mackerel, salmon, pilchards, sardines, trout, kippers, herring and fresh tuna, as well as plant foods such as flaxseed, rapeseed oil, walnuts and green leafy veg.