Home Food Blue fish, an essential food

Blue fish, an essential food


We know that oily fish is a food with many benefits but we are going to discover how we should consume it, preserve it and the differences between the different types of oily fish

Fish is a fundamentally protein food since among its composition, in addition to around 70% water, we find 20-25% proteins, which are of high biological value because they are of animal origin. It does not provide us with carbohydrates and, on the contrary, it does have a remarkable percentage of fats (between 6 and 12%), among which polyunsaturated fatty acids normally predominate . At the vitamin level, we can highlight the fat-soluble vitamins A, D and E, and also the water – soluble B complex (B1, B2, B3, B12). As for minerals, it gives us calcium, especially if it is consumed with thorn, as well as iodine, magnesium and phosphorus.

Has healthy fats

The fats are necessary for the body and the fish has the distinction of providing a type of fat which a number of benefits are derived cardiovascular level . This is due to the known polyunsaturated fatty acids of the omega 3 group , with effects to prevent and even improve cardiovascular risk factors. They are credited with the ability to increase HDL (good) cholesterol and lower LDL (bad), total cholesterol, and triglycerides. In addition, from these fatty acids substances are generated in the body that can reduce the risk of thrombosis and hypertension and that they have anti-inflammatory effects that can even be positive at the muscular level.

A group with very different components

From small fish, such as anchovies or sardines, to large red tuna, we find a great variety of species classified as blue fish since they share a series of characteristics. They are more active fish than white fish and that is why they have a more powerful tail fin and a higher fat content , higher than 5%, compared to 1-2% of white fish. Another different group is that of the so-called semi-fatty fish, which contain between 2 and 5% fat, and that we often include within the group of oily fish. This is the case of caella, sea bass, sea bream, musola, emperor or swordfish, etc. The most frequently consumed blue fish specimens are:

  • Small fish , such as mackerel, anchovies, sardines, boga, horse mackerel, and southern starlings or mackerel.
  • Salmon : a traveling fish that can measure up to 80 cm. It has a bluish skin color and a pink interior, hence its name. Both its color and its flavor are unmistakable.
  • Tuna : large and highly appreciated fish that can measure up to two meters and weigh 200 kg. Its flesh is reddish and we can distinguish different species with similar but not identical characteristics.

How to consume it

Blue fish allows us many cooking and presentations, especially taking into account the variety of specimens. Some ways to consume fresh fish (or previously frozen and thawed) are: grilled or grilled, floured or fried, especially the little ones, pickled such as anchovies, baked or in papillote so that they keep all their juice, in stews or smoked (such as salmon) that we can use in appetizers, salads, pasta dishes, etc. Oily fish also has a great market in canned food, canned in natural or oil, as well as in glass jars.

Of all these preparations, we must prioritize the healthiest ones such as the grill, the grill, the papillote, the oven (without adding fat), etc. On the contrary, it is a question of not basing the consumption of oily fish on fried or canned fish, whether smoked, pickled or canned, since, for example, they tend to have a higher sodium content. Likewise, we must avoid preserves in which the origin of the oil is not specified or simply vegetable oil is indicated, since the quality and nutritional composition of these oils will always be lower than that of olive.


For the majority of the population, an intake of blue fish equal to or greater than twice a week is recommended. In the case of people with an increased cardiovascular risk, consumption should be three or four times a week.

Who is it good for and who is not?

  • People with increased cardiovascular risk: its content in omega 3 fatty acids reduces platelet aggregation problems at the circulatory level and the inflammatory response. All this entails a lower risk at the coronary level.
  • In growth stages: it is very interesting in moments of cell growth and development, such as childhood or pregnancy. This is due to its content of omega-3 fatty acids, essential amino acids, vitamins and minerals. In fact, omega-3 needs are increased during pregnancy due to the important role of these fatty acids in the development of the central nervous system, the retina, and cell membranes.
  • For bone health: in children, adolescents, pregnant women, infants and women in general with low calcium deposits, oily fish can be helpful to increase the contribution of this mineral, promoting proper bone and dental health. The fish that are going to provide the most calcium are the small fish that are eaten with thorn. Calcium, in addition to contributing to the formation and regeneration of bones and muscles, is involved in muscle contraction, in the transmission of the nerve impulse and in blood coagulation.

In certain cases the consumption of oily fish should be limited:

  • Hyperuricemia or gout: People with hyperuricemia should limit or avoid consumption of foods rich in purines such as shellfish and oily fish. In this case, it should be taken a maximum of once or twice a week.
  • Large fish in pregnant women, infants and very young children: methylmercury is a metal found in the environment and the levels that we can ingest through large species of blue fish such as emperor or swordfish, dogfish or bluefin tuna can adversely affect people who are especially sensitive to the effects of this poison. Pregnant, lactating and very young children are considered sensitive.
  • People allergic to fish: fish (and specifically its proteins) are one of the foods that causes the greatest number of allergies. The most common symptoms are located mainly at the respiratory level, on the skin, in the gastrointestinal system and at the central nervous system level. In allergic people the treatment consists of eliminating fish and derivatives from the diet.

Buying and conservation advice

Fish is an extremely perishable product, which is why a good choice of the products we purchase and proper conservation are very important. When choosing a fish we must pay attention to:

  • The gills: they should be pink to deep red in color and have a wet, shiny and smooth appearance.
  • The eyes: they should not be sunken, nor with the iris stained red. They have to be shiny and transparent.
  • The body: must be arched and rigid.
  • The skin: moist (which does not mean watered by the water that has released the conservation ice). It must preserve the colors of each species without spots or wrinkles.
  • The scales: they have to be well adhered to the body, that they do not come off on their own, joined together and shiny, not viscous.

In addition, we must leave the purchase of the fish for when we have acquired the rest of the products that we intend to buy. This will prevent the time the fish spends at room temperature from lengthening.

Once we get home, we must freeze it or keep it quickly in the refrigerator in the lower rack of the refrigerator, preventing it from releasing fluids that can contaminate other foods. It should not be kept in the refrigerator for more than one day. If we want to keep it once cooked, we should not keep it for more than two or three days.

Freezing and thawing

For freezing we can use specific plastic bags for this purpose or containers suitable for it. It is preferable to freeze in individual servings for faster freezing and easier subsequent defrosting. It should be remembered that it is always advisable to freeze the fish to avoid a possible parasite or allergic reaction due to anisakis, a parasite that dies when frozen at -20ºC for a minimum of 24 hours. It also dies with cooking, but for this we must ensure that all areas of the fish have exceeded 60ºC for a minimum of 10 minutes.

The time that we can keep blue fish frozen can be up to two months, just like shellfish. If it were white fish, we could keep it frozen for up to 5 months. This difference is due to the fat content of oily fish, since lipid oxidation is one of the few degradations that a food can undergo that continues to evolve even when frozen. To defrost the fish we must do it in the refrigerator. Only in certain fish and cooking can it be defrosted directly while cooking. For its part, when the frozen fish is vacuum packed, we can defrost it in cold water.

Salmon and dill recipe


  1. Sliced ​​salmon or loins
  2. Dill
  3. Lemon
  4. Extra virgin olive oil


In a frying pan with the hot oil, place the loin (s) with the salmon slice. To prevent it from being dry, we can cover the pan, although cooking is brief and always under surveillance. When we assess that it is golden, we will turn around and sprinkle with the fresh juice of half a lemon, or less quantity if we do not want to notice the lemon too much. Then we will repeat the operation on the other side. Shortly before finishing cooking we will do the same but sprinkle dill on top.

Note: you can complement the dish with some steamed or baked potatoes and a little salad.

What you should know…
  • It stands out for… its high protein value and its contribution of omega-3 fatty acids, allies of cardiovascular health.
  • It also provides … vitamins A, D, E and the B complex, as well as calcium, iodine and magnesium.
  • They belong to this group: salmon, sardines, mackerel, tuna, horse mackerel …


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