The fishing industry: The unhealthy option

Fish, such as sea trout, are almost one-third fat and salmon meat is more than 50 per cent fat. Ounce for ounce, shrimp has double the cholesterol of beef. And while fish and fish oil capsules do contain essential fatty acids, such as omega 3, a 2013 study found that omega-3 fatty acids from fish are linked to an increased incidence of aggressive prostate cancer. Researchers found that eating just over two portions of salmon per week could raise the risk by 71 per cent. (Vegetarians and vegans can meet all their omega-3 requirements from non-animal sources, such as flaxseed, walnuts, rapeseed oil, dark green vegetables such as kale and spinach, and soya products such as tofu. Cauliflower, berries and seaweed also contain omega 3 fats.)

Our seas and rivers are increasingly contaminated with pollutants from industrial and agricultural wastes. Fish are literally swimming in our filth. Many toxins in the environment, such as PCBs (polychlorinated biphenyls) and dioxins, which have been linked to cancer and birth defects, build up in the fat of fish. Fears over possible toxin contamination in fish have led the Food Standards Agency (FSA) to advise on maximum levels of fish consumption. It advises that girls under 16, women who might have a child one day and women who are pregnant or breastfeeding, should have no more than two portions of oily fish a week (one portion is 140g).

Fish, and particularly shellfish, are the main sources of mercury in the diet. Nearly all fish contain traces of mercury. Mercury is a poison that can affect the central nervous system, kidneys and heart. Researchers have found that a high intake of mercury, specifically from eating non-fatty fish, is also associated with an increased risk of mortality from coronary heart disease. If pregnant women are exposed to sufficiently high levels, mercury can harm the developing nervous system of an unborn child. As a result, pregnant women and those who may become pregnant, are advised by the FSA to limit the amount of tinned tuna that they eat.

It is estimated that the risk of food poisoning from eating fish is far greater than that from eating beef, poultry or pork. This is because fish and the bacteria living on them flourish in the kind of temperatures found in refrigerators. Trimethylamine is the chemical that produces the ‘fishy’ smell we all recognise. This odour is produced as the fish begins to go off.