Fish is recommended food and consumption of fish should be increased. Fish contains healthy fatty acids, several vitamins and minerals and a lot of protein. Fish is a particularly good source of n-3 fatty acids and vitamin D. The useful fatty acids contained in fish have been shown to reduce the risk of cardiovascular diseases.
The National Nutrition Council recommends that
- fish should be eaten at least twice a week
- different fish species should be varied in the diet.
Exceptions to dietary advice on fish consumption [1]
Despite the favourable nutritional qualities of fish, the consumption of salmon or trout and herring caught in the Baltic Sea, particularly in the Gulf of Bothnia and the Gulf of Finland, may subject consumers to higher than normal levels of dioxins and PCB compounds, which are harmful to health. Also, higher than normal levels of methylmercury can be derived from predatory fish, particularly pike, caught in inland waters, but also from pike caught in the sea. The older the fish, the more contaminants will have accumulated in it.
For these reasons the Finnish Food Authority has issued the following exceptions to the general dietary advice on fish consumption:
- Children, young people and persons of fertile age may not eat large herring, which uncleaned are longer than 17 cm, or alternatively salmon or trout caught in the Baltic Sea more often than once or twice a month.
- Children, young people and persons of fertile age may not eat pike caught in a lake or in the sea more often than once or twice a month.
- Pregnant women and nursing mothers should not eat pike at all due to the mercury accumulated in pike.
- Persons who eat fish from inland waters on a daily basis are advised to reduce their consumption of also other predatory fish that accumulate mercury. Apart from pike, these include large perches, pike perches and burbots
Fish contaminants and consumption restrictions
The purpose of dietary advice is to ensure the safe consumption of fish. The advice is related to dioxins, PCB compounds, mercury and cesium-137 contained in fish. The safety assessments are based on a portion size of 100 g of fish. If the portion eaten is smaller, fish can be eaten more often. Herring as well as salmon or trout caught in the Baltic Sea as well as predatory fish from inland waters can be eaten from time to time. In summer, for example, they can be eaten in larger amounts, as long as the total annual consumption is balanced and restricted.
Part (up to one third) of the dioxins and PCB compounds accumulated in fish fat can be removed by skinning the fish before preparing it for food. The exceptions to dietary advice do not apply to small herring, which uncleaned are less than 17 cm long. Filleted herring are usually large, longer than 17 cm.
Dioxin and PCB levels in fish from inland waters are normally low, and mercury levels are lower in other lake fish than in pike. The mercury and cesium-137 levels of fish vary from one lake to the other.
Farmed fish contains only low levels of dioxins and PCB compounds, thanks to the control of fish feed quality.
[1] Recommendation issued by the Finnish Food Safety Authority based on contaminant levels.