On the Menu: Serve up seafood for better health
The general guideline is to eat two servings of fish each week – one oily and one white
Herb and lemon fish and prawn casserole.
Turbot with crushed potatoes and sauce vierge.
There’s an old saying that fish is good for the brain. This was not based on scientific evidence but presumably on “wise observation” over generations, according to Prof Ronan Gormley of UCD’s Institute of Food and Health.
Most research today is focused on oily fish, rich in these omega-3 fatty acids, called eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. The latter is the one most important for brain development, while both may be beneficial for cognitive function throughout life.
Oily fish has other anti-inflammatory properties associated with reduced cardiovascular disease risk via these beneficial fats, EPA and DHA. They help to thin the blood, thereby reducing the probability of clot formation.
An analysis of 20 studies involving hundreds of thousands of participants indicates that eating about one to two three-ounce servings of oily fish a week reduces the risk of dying from heart disease by 36 per cent.
The recommended minimum daily intake of EPA/DHA varies from 250mg (EU dietary reference value) to 1,250mg (British Nutrition Foundation). Gormley suggests that an average serving of salmon or mackerel will easily supply these amounts, but to be sure to consume the brown flesh as this contains most of the oil. Unfortunately, it’s the bit I like least.
Oily fish (mackerel, herring, salmon) contain about 20 per cent protein but their water (62-70 per cent) and oil contents (10-18 per cent) vary depending on their condition.
You will know a well-conditioned fish, with a good healthy oil content, when you grill it over a tinfoil-lined tray. Droplets ooze from the fish, whereas recent spawners may show virtually no oil. Gormley advises us not to throw away the oil from the tray. Instead, pour it over your potatoes, rice or vegetables.
You may be wondering if your favourite white fish has specific healthy attributes. Does it deserve some space on your plate?
White fish (turbot, cod, hake) contain about 20 per cent protein, 77 per cent water and only 3 per cent oil. With such small levels of omega-3 fats, the focus of Irish research in 2006 by Seafoodplus was on the amino acid taurine.
Taurine, first found in bulls’ blood, is associated with osmoregulation and plays an important role in controlling blood pressure, blood clotting, neuronal activity and in maintaining a healthy heart rhythm. Taurine also acts as an anti-inflammatory agent.
Norwegian research found that taurine exhibits a synergistic effect with omega-3 fatty acids, resulting in higher healthy HDL cholesterol and lower undesirable LDL cholesterol levels, in 110 healthy human subjects.
In 2003 a study by Fennessy in Beaumont Hospital, Dublin showed that taurine (1g/day) helped to restore normal elasticity to the brachial artery of young smokers.
The positive effects of taurine on cardiovascular health continue to be the focus of researchers in the US and China.
These potential benefits of taurine prompted a study by Gormley to determine levels in a number of fish species.
Over a period of months, 96 raw portions of plaice, cod, mackerel and farmed salmon were obtained from the ice counter of a Dublin supermarket and were tested for taurine content.
The mean values were 120 (plaice), 88 (cod), 63 (mackerel) and 48mg/100g (farmed salmon). The conclusion was that white fish had more taurine than oily fish among the four species.