The most concentrated source of energy in the diet is fats. They are a source of fatty acids, including essential unsaturated fatty acids (EFAs). It is in them that some vitamins are found (A, D, E, K - soluble in fats). Fat also provides, among other things, the building materials of cells, tissues and organs.
The health benefits of eating fish are due to the presence of polyunsaturated (mainly omega-3) and monounsaturated (MUFA) fatty acids. Fish are also a valuable source of proteins, minerals (selenium, potassium) and vitamins necessary for good health.
Depending on the number of double bonds, fatty acids have been classified into one of the following groups:
Green unsaturated, or polyunsaturated, fatty acids contain more than one double bond and, depending on the position of the first one, they are divided into two groups:
The only authentic sources of omega-3 fatty acids, especially the long-chain fractions, i.e. eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are fats derived from fish and marine animals. This is because fatty acids from the omega-3 family (α-linolenic - C18:3) and omega-6 (linoleic acid - C18:2) are not synthesised in the human body. Neither our organism, nor organisms of most animals possess enzymes from the desaturase class, introducing a double bond in the acid molecule at carbons 3 and 6.
Since we cannot synthesise these acids ourselves,& nbsp; they must be supplied with food. Polyunsaturated fatty acids are also found in plants, but their overall amount is very small, and thus they provide too little α-linolenic acid for our metabolic needs.
The action of polyunsaturated fatty acids PUFAs in the body is largely related to the activity of eicosanoids synthesised thanks to them. PUFAs have different biological effects. Eicosapentaenoic acid mainly stimulates the cardiovascular system by influencing the synthesis of eicansanoids, while docosahexaenoic acid is an important structural component of nervous tissue.
The positive effects of polyunsaturated fatty acids include the following:
According to the recommendations, the amount of energy derived from the consumption of linoleic acid (LA) should be 2 percent, while for α-linolenic acid (ALA) it should be 0.7 percent. (in our 24-hour diet, fats provide about 35-40 percent). The recommended intake of the sum of EPA and DHA acids is between 250 and 500 mg per day, which corresponds to eating at least two portions of oily fish per week.
According to the European Food Safety Authority (EFSA), 250 mg of EPA + DHA daily is sufficient for a health effect in cardiovascular prevention. Pregnant and lactating women should increase this dose by 100 -200 mg of DHA to compensate for the losses associated with the oxidation of DHA acid in the mother's body and accumulation in the fatty tissue of the fetus or child. The diet of older infants should contain 50 - 100 mg DHA per day, children aged 7 - 24 months -& nbsp; 100 mg DHA. Dietary recommendations for children and adolescents aged 2 to 18 years are the same as for adults.