Selenium, first discovered in 1817 by the Swedish chemist Berzelius, was named "selenium" after the Greek moon goddess Serene, meaning to protect human health. In 1973, the World Health Organization announced that selenium is an essential trace element in human and animal life, and the lack of selenium in the human body will lead to the occurrence of many diseases. Over the years, with the gradual deepening of research, the mystery of selenium has also been gradually unveiled, and it has also been given many reputations, such as "life fire", "longevity element", "king of anti-cancer", "heart guardian" and so on.
Physiological function of selenium
Among the many physiological functions of selenium, the most important is the antioxidant function. The importance of oxygen in life must be well known, but many people do not necessarily know that the body will produce some by-products when it is aerobic metabolism, such as peroxides and oxygen-containing free radicals, etc. These oxygen-containing active molecules are very active in the body, which can promote lipid peroxidation reactions, make lipid compounds in the body deteriorate, and release more free radicals at the same time; it will also involve other biological macromolecules such as proteins, causing damage to the body, thus causing health problems related to free radicals, such as aging, atherosclerosis, arthritis, Tumors, cataracts, etc. Therefore, the oxygen free radical theory is one of the most well-known theories of aging.
Soldiers will come to block, water will come to cover. In the process of evolution, in order to deal with excess reactive oxygen species and free radicals, the body has developed a perfect antioxidant skills, one of the major weapons is antioxidant enzymes, glutathione peroxidase (GSH-Px) belongs to this category, they are all over the body in various tissues and organs. Selenium is an essential component of glutathione peroxidase, and each GSH-Px molecule contains 4 atoms of selenium, revealing the first bioactive form of selenium. Glutathione peroxidase can reduce peroxides that are toxic to the body into harmless substances, and can also capture free radicals to prevent them from attacking biological macromolecules and damaging the body.
It is conceivable that if the body is deficient in selenium, the body's antioxidant capacity will be damaged, causing an enhanced lipid peroxidation reaction, resulting in damage to myocardial fibers, myocardial arterioles and capillaries; if the body has sufficient selenium, it can maintain the activity of glutathione peroxidase and reduce the damage caused by free radicals, such as the low incidence of cardiovascular disease in people with high selenium.
In addition to antioxidant functions, selenium also has the functions of improving human immunity, improving visual function, protecting cardiovascular and myocardial health, promoting the excretion of toxic metals from the body, anti-tumor and other functions, which are very important for maintaining and promoting the health of the elderly. Survey studies on china's longevity areas and centenarians have shown that there is a superior trace element spectrum in the natural environment and inside the human body in longevity areas, including selenium, which is considered to be one of the important material bases for centenarians to live a long and healthy life.
About selenium supplementation
Since selenium has so many functions, many people will be concerned about the problem of selenium supplementation. The Chinese Nutrition Society recommends a recommended daily intake of selenium for adults at 60 micrograms. Food is the best and safest way for the body to get nutrients. The absorption rate of selenium in food is about 80%, which is higher than the absorption rate of inorganic selenium in water (50%). Foods with high selenium content include seafood and animal offal, and for every 100 grams of the same amount of food, caviar contains 203 micrograms of selenium, sea cucumber contains 150 micrograms of selenium, pork loin contains 111.77 micrograms of selenium, pork liver contains 28.7 micrograms of selenium, and pork contains 11.97 micrograms of selenium. The content of selenium in plant foods varies greatly depending on the content of selenium in the soil of the planting site.
However, selenium intake is not as much as possible, and clinical studies have shown that when the concentration of blood selenium reaches a certain level, the level of glutathione peroxidase is no longer elevated. And excessive selenium supplementation may pose potential risks, such as high doses of selenium can lead to growth retardation in children, but also can cause hair and nail loss, skin damage and neurological abnormalities, and even death. Therefore, the Chinese Nutrition Society recommends a maximum tolerable intake of selenium at 400 micrograms. Therefore, selenium supplementation must be strictly cautious.
In short, selenium as an essential trace element, the diet can not be lacking, otherwise it will be detrimental to human health, but if selenium supplementation should not be too much.
Contributed □ the Chinese Nutrition Society
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Source: China Market Supervision News