Salmon is an oily fish and an excellent source of omega–3 fatty acid, which is essential for brain function and warding off heart disease. Fresh, smoked and tinned salmon all have the same levels.

You will find 2.1g of omega 3 in a 100g fillet of fresh salmon and similar amounts in the same sized piece of smoked and tinned fish – 2g and 1.9g respectively. This is more than the recommended daily amount – 241 mg.

The worst form to buy is frozen, where you’ll find only 0.9g per 100g. This is because the omega–3 fatty acids in frozen fish degrade over time. In tinned salmon, the fatty acids degrade far more slowly, whereas in smoked salmon the smoking process has no impact on the fatty acids.

The source of the salmon also has an impact on its omega–3 content – wild salmon has more of the fatty acid than farmed salmon, because wild salmon have a carnivorous diet, while farmed fish are fed on plants.