Fish is a valuable food product. In terms of nutrition, it rivals the best varieties of meat, but unlike meat, it is faster and easier to digest by the body, and therefore is often used in dietary and children's food, in the menu for the elderly and people who are obese. 

Low-fat fish (1-4% fat) and medium-fat fish (fat content ranges from 4 to 8%) are used in dietary and therapeutic nutrition. This includes: Pollock, cod, whiting, hake, walleye, pike, carp, bream, sea bass, catfish and horse mackerel. 

Recent studies have found that people who eat mainly fish, rather than meat, are less likely to get colon cancer. Despite the fact that fish is a low-calorie product, it is rich in protein, vitamins B6, B12, B3, PP, H, D, mineral elements (phosphorus, copper, potassium, manganese, magnesium, sulfur, iodine, bromine, fluorine, chromium, cobalt, sodium, iron, zinc, chlorine), amino acids, proteins and fats. So what do we need these substances for? 

1) fish Protein is nutritionally not inferior to meat and is not burdened with harmful saturated fats. 

2)Vitamin B6serves to strengthen the immune system and improve mood. 

3) Vitamin B12, found in large quantities in salmon, tuna and mackerel meat, contributes to the formation of red blood cells and the normal functioning of the nervous system. 

4)Vitamin D is very important for bones, and the best source of it is fish oil. 

5) Iron, which is enriched with sardines and mackerel – is a necessary element for the transfer of oxygen by the blood. Its deficiency leads to anemia.

6) Vitamin B3 (Niacin) helps the body get energy from carbohydrates. 

7) Omega-3 fatty acids help prevent asthma, hypertension, depression, coronary heart disease, psoriasis, and rheumatoid arthritis; they are found in large quantities in oily fish (meat contains more than 9% fat).

8) Tyrosine is an amino acid necessary for the synthesis of hormones and neurotransmitters, so it is believed to promote mental health. 

9) Phosphorus stimulates the brain. Small fish, cod and fish oil are especially rich in phosphorus. It is known that phosphorus is necessary for the normal functioning of cells of the Central nervous system and the formation of nervous tissue, its salts are involved in the formation of teeth and bones, and also regulate the exchange of carbohydrates. Lack of phosphorus in the body causes rapid fatigue, lethargy, reduces resistance to diseases. 

10) Iodine is necessary for the normal functioning of the thyroid gland. Doctors recommend sea and ocean fish to people with a sick stomach and unhealthy liver. By the way, 200 grams of mackerel contains a daily dose of iodine. In General, for people with a sick liver, boiled cod, Saida, haddock, navaga, bream and pike are especially useful, since their meat has a more tender consistency and does not hinder the digestion process. 

11) the Fat of most fish (especially liver fat) is easily absorbed by the human body. In the body of a fish, it is located in the subcutaneous layer, in the abdominal and dorsal parts, between the muscles, near the bones, in the head, near the internal organs, near the fins and in the liver. The fat content of fish is one of the main criteria for its nutritional and energy value. The best taste qualities are those fish whose fat is concentrated between the muscles or under the skin: halibut, tuna, mackerel and sturgeon. Fish oil, which contains iodine, as well as vitamins A and D, is very useful for the brain and heart. Especially useful is the liver fat of halibut, tuna and cod. 

12) along with chicken meat, fish is one of the best sources of high-quality protein – because proteins make up 1/5 of its tissues! It is known that protein is associated with the body's metabolism, as well as muscle contraction, the ability to grow and reproduce. Lack of protein negatively affects the ability to work and the body's resistance to colds and infectious diseases. Especially rich in protein: whitefish, salmon, sturgeon, cod, salmon and rainbow trout.