Q. What fish are oily and what is the best way to cook them to preserve their nutrients?

A. Eating oily fish twice a week is recommended for your overall good health, especially for your heart and blood. Oily fish varieties include small fish such as anchovies, sardines, herring and kippers as well as larger types like ocean tuna, Atlantic salmon, Spanish various mackerels, eel, trout, silver warehou, mullet, trevally, sand whiting and snapper. You don't have to eat these fish fresh.

Frozen, smoked or canned are also good for the omega-3s, the long-chain fatty acids considered the active agents in oily fish.

Canned sardines, salmon and tuna are convenient and inexpensive. I like to keep a can or two in the kitchen cupboard for quick meals with a salad or sandwich. For canned tuna, check the label for a claim "High in omega-3" as many brands have had their natural oil reduced during canning.

Compared to white fish like bream, oily types are darker in colour, stronger in flavour with a high fat content in their flesh (anywhere from 7 to 20 per cent compared to white at less than 3 per cent). But they have 5 to 6 times more omega-3 than white fish. Whilst these fats won't lower cholesterol, they will keep the heart rhythm steady, the blood free-flowing and blood triglycerides down.

In addition, oily fish are rich in vitamin A and vitamin D, a vitamin that is often hard to obtain from food alone (it is made by the action of sunlight on the skin but this process declines with age).

Best ways to cook

The best cooking methods are barbecuing, baking, steaming or lightly pan frying as these don't add extra fat (think extra kilojoules/calories). Heat does not affect the omega-3s, so they're present in canned varieties as well as fresh.

Try my recipe for Baked fish parcels: Wrap fillets of oily fish in baking paper or foil with lemon slices, onion slices and fresh dill (or a sprinkle of herbs) and bake in the oven for 4-5 minutes or until soft. Serve with baked potato and green beans or a leaf salad.