Selenium is one of the essential 14 trace elements for human body. In recent 20 years, more and more studies have found that selenium has biological functions such as scavenging free radicals, anticancer, liver protection, anti-aging and enhancing immunity. The selenium needed by animals and people mainly depends on food intake, but the toxic dose and beneficial dose range of selenium is very narrow, generally between 30 ixg/d and 400 p ~ g/d, and below 30g, it shows selenium deficiency, such as high incidence of genetic diseases such as aging and myocarditis. If it is higher than the upper limit, it will lead to hair loss or easy breakage of hair and nails, gastrointestinal dysfunction, rough skin, irritability and neurological dysfunction. There are many selenium-enriched foods on the market. Whether the selenium content in some foods is safe to eat, the existing form and bioavailability of selenium in foods are all concerned by scholars in various scientific research fields. Selenium and vitamin E are both antioxidants, and they complement each other, which can prevent aging and tissue sclerosis caused by oxidation and slow down their changes. It also has the functions of activating the immune system and preventing cancer. 100 microgram is an essential trace element for human body. The combination of plant active selenium with vitamin E and β -carotene can enhance human immune function, resist oxidation, delay aging and effectively inhibit tumor growth. Scientific research has found that blood selenium level is closely related to the occurrence of cancer. A large number of survey data show that the level of selenium in food and soil in an area is directly related to the incidence of cancer. Selenium is the most important anti-aging element discovered so far; Bama County, Guangxi is one of the four famous longevity areas in the world. The study of Bama by experts from Chinese Academy of Sciences shows that the selenium content in soil and grain in Bama is 10 times of the national average, and the selenium content in blood of centenarians is 3-6 times of that of normal people. Later, another longevity village was discovered in shitai county. The elderly over 80 years old account for 12% of the village population. More strangely, no cancer patients, cardiovascular and cerebrovascular patients, diabetic patients and obese patients have been found in the past 50 years. The analysis and determination of selenium content in the soil of this village showed that the selenium content was 10 times higher than that in other places. It turns out that selenium is the active component of glutathione peroxidase, and the human body can effectively scavenge free radicals, resist oxidation and delay aging by supplementing enough selenium. If vitamin E and β -carotene are supplemented in selenium, the effect will be better. [ 1]? Bright angel biologists have found through long-term research that selenium is extremely important to the function of visual organs. Selenium can catalyze and eliminate free radical substances harmful to eyes, thus protecting the cell membrane of eyes. If the human eye is in a state of selenium deficiency for a long time, it will affect the integrity of cell membrane, lead to decreased vision, and lead to cataract, retinopathy, night blindness and other eye diseases. Hospitals in some big cities have carried out selenium therapy for patients with eye diseases. Clinically, selenium can obviously improve vision and treat eye diseases such as cataract and retinopathy. Selenium is the patron saint of the heart, an important element to maintain the normal function of the heart, and has protective and repair effects on the heart. The decrease of human blood selenium level will lead to the decrease of the function of scavenging free radicals in the body, which will lead to the increase of harmful substances deposition, the increase of blood pressure, the thickening of blood vessel wall, the decrease of blood vessel elasticity, the slow blood flow and the decrease of oxygen transport function, thus inducing the increase of the incidence of cardiovascular and cerebrovascular diseases. However, scientific selenium supplementation has a good effect on preventing cardiovascular and cerebrovascular diseases, hypertension and arteriosclerosis. The natural enemy of liver disease is located in Qidong, Jiangsu, a land of plenty and developed economy in the Yangtze River Delta. But for a long time, the incidence of liver cancer and hepatitis here is extremely high, and the cause is unknown. After 16 years of research, experts from Chinese Academy of Preventive Medicine finally found the reason. It turns out that the water, soil and grain here all lack the element "selenium". People living here get little selenium from water and grain, and the selenium content in their bodies is particularly low. People who lack selenium in their bodies are prone to hepatitis virus infection. In addition, the risk of hepatitis patients with long-term selenium deficiency turning into liver cancer patients is 202 times that of other people. It is particularly worth mentioning that selenium can improve the condition of hepatitis patients and greatly reduce the proportion of cancer in hepatitis patients. Experts said: Even in the surrounding areas where selenium is not lacking, it is of great benefit for people to supplement selenium in moderation to prevent liver cancer and hepatitis. [2]? Insulin selenium in trace elements is the active component of glutathione peroxidase, which can prevent the oxidative damage of islet β cells, make them function normally, promote glucose metabolism, and reduce blood sugar and urine sugar. Doctors can protect and restore the function of pancreatic islets by letting diabetic patients take selenium quantitatively, which is beneficial to improve the symptoms of diabetes and reduce the levels of glucose and hemoglobin in urine. So some people call selenium "insulin" in trace elements. Detoxifying and detoxicating selenium has strong binding force with metals, and can resist the toxicity of cadmium to kidney, gonad and central nervous system. Selenium combines with mercury, tin, thallium, lead and other heavy metals in the body to form a metal selenoprotein complex, which plays the role of detoxification. Therefore, people who are often exposed to toxic and harmful work need to pay special attention to selenium supplementation. In addition, in the working environment or life, people who are often exposed to radiation interference such as TV, computer and mobile phone should be supplemented with selenium, because selenium supplementation can protect the hematopoietic system and minimize radiation damage. The important nutritional and physiological function of antioxidant and anti-aging selenium is to participate in the synthesis of glutathione peroxidase (GSH-PX), which is the active central element of GSH-PX, and its antioxidant effect is also realized by GSH oxidase. GSH-PX has a strong reducing effect on hydrogen or lipid peroxide in vivo. The catalytic reduction of GSH reduces harmful unsaturated hydroperoxide (ROOH) to harmless hydroxyl compounds and decomposes hydrogen peroxide (H202), thus protecting the structural integrity of cell membrane. Liu Chunren (1996) reported that selenium deficiency can reduce the activity of glutathione peroxidase in animals, which leads to the failure of tissue peroxide decomposition in time and causes damage to tissues, while selenium supplementation can increase its enzyme activity. Gold research in men shows that selenium is the only atom in GSH-PX that catalyzes oxidation and reduction, and selenocysteine in polypeptide chain is the catalytic part of the enzyme, in which -SeH stands for the active reduction form of the enzyme. Selenium, as an important component and active center of GSH-PX, can protect the cell membrane from peroxide, reduce the cell dissociation rate, and thus maintain the normal physiological function of cells. Allen et al. (1995) reported that there is a strong correlation between selenium levels in blood and organs and GSH-OXA activity. The order of selenium content in male tissue fluid is kidney > liver > testis > myocardium. 25%-40% selenium in male body is concentrated in reproductive system, and selenium can enhance sperm vitality and sexual function. So people call selenium gold in men. Diabetes, heart disease, liver disease and urinary system all have different degrees of sexual dysfunction. Selenium supplementation can regulate immune function and antioxidant function. Selenium can improve and enhance sexual function, and help people with impotence, premature ejaculation and sexual dysfunction gradually return to normal. The study also found that female abortion and unexplained infertility are related to low sperm levels. A recent survey in the United States shows that the risk of spontaneous abortion in women is related to the low selenium content in the body. In the past few years, researchers have confirmed two sperm-specific selenoproteins. One is GSH-Px specific to sperm nucleus, and the other is found in the middle of sperm, which has the functions of enzyme and structure. Sperm does not swim because its middle part is damaged (such as the tail of sperm is broken). Selenium deficiency will hinder testicular development. After taking organic selenium for 3 months, the rate of becoming a father will increase 1 1%. Patients with liver diseases (hepatitis, fatty liver, liver cirrhosis, liver cancer, etc.). ) among the people in need; Patients with cardiovascular and cerebrovascular diseases; Diabetic patients; Cancer patients; Patients with gastrointestinal diseases; Workers engaged in toxic and harmful operations; Fatigue-prone people and perennial smokers; Children and adolescents with low immunity; Old people who long for health and longevity; Cataract patients; Fitness beautician; People who often make up; Aids patients; Irregular life; People who are often exposed to radiation and environmental pollution; Patients with prostate diseases. Recommend the method of selenium supplement? The Recommended Dietary Allowance for Daily Diets revised by China Nutrition Society/KLOC-0 in June, 1998 has listed selenium as one of the daily dietary nutrients of 15, and put forward that the suitable intake of selenium for an adult is 50-250 micrograms per day. It is the traditional understanding of China people that "medicine is better than food". Common flour, brown rice, barley, fish, shrimp, seaweed, animal liver, animal kidney, garlic, onion, asparagus and carrots all contain selenium. It should be pointed out that the high content of selenium in food does not mean that people will absorb it. Generally speaking, the utilization rate of organic selenium is high, which can reach more than 70%. Therefore, the correct way to supplement selenium is to eat more foods supplemented with organic selenium, fruits, vegetables and other foods rich in vitamins A, C and E to promote the absorption of selenium. Selenium, like other mineral elements, has duality, that is, moderate amount is beneficial and excessive amount is harmful. Although it is necessary to supplement selenium, we should not blindly supplement selenium, which may have side effects. The scientific method of selenium supplement is: 1. Artificial selenium supplement: the intake of various selenium supplement products added artificially is mainly divided into inorganic selenium and organic selenium. Inorganic selenium, mainly sodium selenite, is mostly used in feed abroad, which is highly toxic and on the verge of technical elimination. Compared with inorganic selenium such as sodium selenite, organic selenium has the advantages of food safety, no toxic side effects, high absorption and utilization rate, and high nutritional value (such as high-level vitamins and high-quality protein). There are many kinds of organic selenium, such as selenium yeast, selenium eggs, selenium-enriched seaweed, selenium-enriched mushrooms and selenium malt. Among them, malt selenium is the highest stage of organic selenium development at present, which has better activity, higher utilization rate and no cumulative toxicity than mushroom selenium and yeast selenium, and can be taken for a long time. It has no side effects, is beneficial to absorption, and is the ideal first choice for selenium supplementation. 2. Natural selenium supplement: taking wild natural foods with high selenium content, such as pure grain 100 microgram of plant active selenium, and supplementing organic selenium is less toxic than inorganic selenium, but selenium should be supplemented scientifically according to the prescribed intake. Natural selenium food is healthier than inorganic selenium. Using natural selenium supplement method is more beneficial to health than taking inorganic selenium.