Some interesting facts about fish
Fish and shellfish are a fairly common cause of severe food allergy. If you've had one bad reaction, be extremely careful not to eat them a second time.
Some fish are rich in a group of chemicals called purines, which can severely aggravate the painful symptoms of gout. Sufferers of gout should therefore avoid cod and herring roe, caviar, taramasalata, anchovies, whitebait, herrings, sardines, salmon, sprats, mackerel, scallops and mussels. If you suffer from any other forms of arthritis, however you will find oily fish extremely helpful as they have a potent anti-inflammatory action, which can relieve joint and muscle pains.
Avoiding contamination: Contamination with toxic residues and heavy metals is a worry. If you're buying farmed fish, choose organic and avoid all but occasional treats of tune, swordfish and marlin. The health benefits of all other oily fish far outweigh the extremely small risks they pose. All canned tuna is now routinely monitored for mercury contamination.
At the fish counter
When buying fish check, that the eyes are bright and shiny, not dull, that the skin still has lots of scales on and that gills are still red. Fish should always have a fresh smell of the sea - apart from skate which is best eaten when it has a faint smell of ammonia. Look for bright clear spots on plaice and well-defined markings on other fish.
The best ways to cook fish are baking, steaming, grilling or pan-frying in shallow oil, as all these methods minimise the loss of nutrients. Boiling fish results in considerable loss of minerals, especially iodine of which, apart from kelp, fish is the most important source. But as long as you use the cooking water to make sauce for your fish dish, you won't lose out.
When you are buying shellfish check that they feel heavy for their size. All molluscs should be closed and all shellfish should be eaten on the day you buy them. Above all, buy your shellfish from a supplier whose reputation you can rely on.
Watch out for additives in processed fish. Colourings, preservatives and antioxidants are commonly used in the coating of fish fingers, as are brown and yellow dyes in kippers and smoked haddock respectively. Growing public concern about additives means that more manufacturers are producing products without them so undyed kippers and haddock are now widely available.