Selenium is an important trace element to maintain normal physiological function of human body. Selenium is absorbed by the intestine after being ingested by the body and distributed in organs such as liver, spleen, kidney and heart. Selenium is combined with proteins and transported to tissues via blood, and selenium is involved in constituting glutathione peroxidase, which can catalyze the conversion of reduced glutathione into oxidized glutathione and prevent damage to cells from hydrogen peroxide and oxidized lipids. Food sources of selenium The human body cannot synthesize selenium by itself, and selenium in food is the main source. Foods high in protein > foods low in protein contain selenium in the order of animal organs > seafood > fish > eggs > meat > vegetables > fruits. Selenium is mainly found in natural foods, seafood and plant seeds, especially sesame seeds, contain large amounts of selenium. Most antioxidant supplements also contain selenium. Meat from animal organs is often rich in selenium, similar to cereals. Most fruits and vegetables are low in selenium, with garlic being the highest. In addition, the bioavailability of selenium in different foods varies greatly, depending mainly on the chemical form of selenium in the food and various factors that affect its absorption and utilization by the body. Selenium is an essential macronutrient in the human body, the total selenium content in the human body is 6-20mg. selenium is found in all tissues, organs and body fluids, with the highest concentration in the kidney, which is very important for improving immunity and preventing cancer. Selenium in men is mostly concentrated in the testes and prostate gland, vas deferens, and will be excreted with semen. Since there is no long-term storage organ for selenium in the human body, the body should constantly get sufficient amount of selenium from the diet, and the balance of selenium concentration has an important role in protecting and promoting the physiological functions of many organs and tissues. When selenium is deficient, it will easily lead to the decrease of human immunity, and more than forty kinds of diseases that threaten human health and life are related to human selenium deficiency, such as cancer, cardiovascular disease, liver disease, cataract, pancreatic disease, diabetes, reproductive system diseases and other symptoms. Some people think they are selenium deficient, so they blindly supplement selenium. Take high selenium food as nutrition for a long time, so that the body is in a high selenium state. In fact, blind selenium supplementation is undesirable, the human body in a long-term high selenium state manifested as dull skin pain, numbness of the limbs, dizziness, loss of appetite, hair loss, nail thickening, rash, itchy skin, pale face, gastrointestinal disorders, indigestion and other symptoms. Normally, the total daily requirement per person, Chinese adults have a health effect of more than 25 micrograms of selenium supplementation outside food per day; selenium-deficient adults have more than 50 micrograms or 75 micrograms of selenium supplementation outside food per day, in natural foods, selenium-rich rice, selenium-rich wheat, seafood, mushrooms, eggs, garlic, ginkgo, etc. contain high selenium, selenium-deficient people can properly increase the food in this regard, normal people, just need to Maintain a balanced diet can take in sufficient selenium.