About 32,000 species of fish have been found in the world. Fish live in water, distributed in the ocean and fresh water, of which two thirds live in the ocean and the rest live in fresh water.
At present, there are about 32 100 species of named fish in the world. Among them, there are about 73 species of rotifers, 800 species of cartilaginous fishes and 20,000 species of bony fishes. There are about 3000 kinds of fish in China. Among them, there are about 2 100 species of marine fish and about10/0 species of freshwater fish.
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The efficacy and function of fish;
1, Eating fish for depression: It is found that there is a special fatty acid in fish, which is related to the "happy hormone" in the human brain. It has the function of relieving mental tension and balancing emotions. People who don't eat fish or eat less fish often have lower levels of "happy hormones". Americans don't often eat fish, so there are more people suffering from depression.
2. Eat fish to prevent asthma: Unsaturated fatty acids contained in fresh fish can prevent or reduce the production of inflammatory mediators in the human body, and the onset of asthma is closely related to the release of inflammatory mediators. In addition, unsaturated fatty acids can also reduce tracheal inflammation to a certain extent, thus helping to prevent the occurrence and recurrence of asthma or reduce the degree of asthma symptoms.
3. Eat less fish for dementia: Canadian scientists found that the DHA fatty acid content in the blood of healthy elderly people is much higher than that of dementia elderly people, and the DHA content in the blood of dementia patients is 30% ~ 40% lower than that of healthy elderly people on average.
Scientists believe that DHA is an essential nutrient for brain cells to exercise and maintain vitality, which helps to improve nerve information transmission and enhance thinking and memory ability. Therefore, eating more fish in the elderly can reduce the occurrence of dementia.
4, eat fish to prevent stroke: eating more fish has a protective effect on cardiovascular and cerebrovascular diseases. Studies have shown that the higher the content of protein and sulfur-containing amino acids in the diet, the lower the incidence of hypertension.
Fish protein is rich in egg amino acids and taurine, both of which are sulfur-containing amino acids. It can affect the regulation mechanism of blood pressure, increase urinary sodium excretion, thus inhibiting the influence of sodium salt on blood pressure and reducing the incidence of hypertension. Baweifang suggested that one of the effective ways for middle-aged and elderly people to prevent cardiovascular and cerebrovascular diseases is to take three or four grams of fish oil every day.
5, eat fish to prevent aging: There was a famous prime minister in German history, named Bismarck. He has been overeating and smoking too much for years. At the age of 68, he was weak, wrinkled and glassy-eyed, as if death were waving to him.
But then he listened to the doctor and ate herring every day. Soon, a miracle appeared: his skin was rosy, his eyes were bright and he was full of energy, and he lived until he was 83 years old.
A study published in Food Control magazine (one of the most influential nutrition magazines in the world) shows that steamed fish is the healthiest. Steaming for more than 2 minutes can reduce cyanobacterial toxin (a cyanobacterial toxin) by more than 26%, but when cooking fish, the toxin is only reduced by 65,438+08% and will remain in the soup.
References:
Baidu encyclopedia-fish
People's Network-Nutritional Value and Efficacy of Various Fish