The main elements in human nutrition are 1 1 species, which are in descending order of oxygen, carbon, hydrogen, nitrogen, calcium, phosphorus, potassium, sulfur, sodium, chlorine and magnesium. The first four kinds account for 95% of human body weight, and the rest account for about 4% of human body weight. In addition, there are "essential trace elements" in human body to maintain life activities, accounting for less than 1% of human body weight. The content of each trace element is less than 0.065438 0%. They are 10 kinds of iron, copper, zinc, manganese, iodine, cobalt, molybdenum, selenium, fluorine and barium.
zinc (Zn)
The importance of zinc to human body was considered as the key element and wisdom element to promote children's growth in the early days, and now it is known that it is an essential component to maintain the long-term system of various enzymes in human body. It is also an essential element to form various protein molecules, and protein constitutes cells. Therefore, almost all zinc is distributed in cells, and its content is richer than any other element. At present, many research reports show that zinc has many physiological functions and is a vital element for human life. When the human body is short of zinc, it will cause a series of physiological disorders. Although zinc has such a magical effect on human body, too much intake is also harmful. It is generally believed that people need 10~ 14.5 mg of zinc every day, most of which comes from food and drinking water.
iron
Iron is necessary for the exchange of blood and oxygen in mammals. Without iron, hemoglobin cannot be produced and oxygen cannot be transported, leading to iron deficiency anemia. It is worth noting that even children with mild iron deficiency will obviously reduce their attention, which will affect their learning ability. People can get some iron from their diet, such as cereals, meat, vegetables and fruits. The estimated daily intake is 10~ 15 mg, and a certain amount of iron can also be obtained from drinking water.
manganese
Manganese participates in hematopoietic process and plays a role in early embryo. In all kinds of anemia patients, manganese is mostly reduced, and the incidence of cancer in manganese-deficient areas is high. The study also found that patients with arteriosclerosis are due to manganese deficiency in the heart aorta, so arteriosclerosis is related to manganese deficiency in human body. In addition, manganese is also an indispensable part of arginase and proline titanase, and also participates in the process of hematopoiesis and fat metabolism.
copper
Copper is an essential element in human metabolism, which plays an important role in the development and function of blood, central nervous system and immune system, hair, skin and bone tissue, brain, liver, heart and other internal organs. For example, it can change inorganic iron into organic iron, promote iron to enter bone marrow from storage, and accelerate the production of hemoglobin and porphyrin. It is an extremely effective catalyst in redox system. Lack of copper can cause anemia, and hair discoloration often occurs due to insufficient melanin. It can even produce albinism. Studies have proved that copper deficiency can cause symptoms such as heart enlargement, vascular weakness, myocardial degeneration and myocardial hypertrophy, so it is related to coronary heart disease.
cobalt
The effect of cobalt on human body is mainly to exert its physiological function in human body through vitamin B 12, and its biochemical function is to stimulate hematopoiesis and promote the synthesis of animal hemoglobin. Promote the absorption of iron in gastrointestinal tract; Prevent fat from depositing in the liver and bones.
If people lack cobalt, it will cause giant cell anemia and affect the synthesis of protein, amino acids, coenzyme and lipoprotein. In mineral water of some weathered igneous rocks and ultrabasic rocks, the content of cobalt is very high.
molybdenum
The content of molybdenum in drinking water is very low, generally lower than 1 mg/L, which is one of the reasons for the lack of molybdenum in human body. The incidence of esophageal cancer is high in molybdenum-deficient areas. According to the survey data of concentrated and high-incidence areas of esophageal cancer in China, drinking water in epidemic areas is characterized by lack of molybdenum, copper, zinc and manganese. Excessive or insufficient molybdenum intake will cause dental caries, kidney calculi, malnutrition and other symptoms.
chrome
Chromium exists in the form of oxides of Cr3+-Cr6+. But in nature, Cr3+ is the most common. As an essential trace element for human body, its physiological function is limited to the form of Cr3+, which is harmful to human body.
According to a large number of research results, Cr3+ is very necessary for human physiological functions, mainly used for the metabolism of glucose and lipids and the utilization of amino acids in some systems. Therefore, chromium deficiency can easily lead to decreased insulin activity, leading to diabetes. In 1959, the biomedical scientist Mertz confirmed that chromium is an essential element for the utilization of insulin in glucose metabolism. For some children with lipid deficiency in protein in areas with low chromium content in drinking water, the normal digestion of glucose was restored after chromium treatment. At present, there is no clear report on human demand for chromium. According to the intake and absorption, the daily intake of 50~ 1 10 mg is enough to meet the physiological needs.
vanadium
It has certain biological activity and is one of the essential trace elements for human body. Vanadium has a positive effect on hematopoiesis. Vanadium can inhibit the synthesis of cholesterol and lower blood pressure. Vanadium deficiency in animals can cause increased cholesterol content, growth retardation and abnormal bones.
selenium
Selenium, as a trace element needed by human body, plays an important role in preventing and treating cancer, cardiovascular disease, Keshan disease and Kaschin-Beck disease, and is indeed an essential nutrient trace element to maintain human health. The main functions of selenium in human body are as follows: firstly, selenium is an important element of glutathione peroxidase, which participates in the synthesis of coenzyme A and Q and protects the structure of cell membrane; Secondly, it has antioxidant effect and can effectively prevent the formation of peroxide free radicals that induce various cancers. It has been reported that the antioxidant effect of selenium is similar to that of vitamin E, and it is more effective. Besides, selenium can reverse the harmful physiological effects of cadmium. According to the research results at home and abroad, the Keshan Disease Prevention and Control Team of China Academy of Sciences thinks that the minimum daily selenium requirement of adults is 0.03~0.068 mg, and it is estimated that it is 0.04 mg per day. Excessive intake can also lead to chronic poisoning.
iodine
Iodine is an essential trace element for human body. Iodine deficiency in human body will lead to a series of biochemical disorders and physiological abnormalities. However, high-dose iodine supplementation can cause thyroid poisoning. People who consume excessive iodine for a long time are not only useless, but harmful.
fluorine
Fluorine is an essential trace element for human body. For human body, its concentration in human body depends on the external environment. When the fluorine content in the environment is high, especially when the fluorine content in drinking water is high, our intake will be more, and when the environment is short of fluorine, our body will also be short of fluorine. It is generally believed that human physiological demand for fluorine is 0.5~ 1.0 mg/day. Under normal circumstances, adults can get fluoride needed by physiology from ordinary drinking water and diet every day. Because fluorine obtained from drinking water is almost safely absorbed, the content of drinking water plays a decisive role in human health. The fluorine content in drinking water is 0.5 ~1.0 mg/L. When the fluorine content in drinking water is 1.5~2.0 mg/L, sometimes mottled enamel teeth will appear, which will affect the appearance. When the fluorine content reaches 3~6 mg/L, skeletal fluorosis will occur. When the fluorine intake is less than 4~6 mg per day,
Fluorine plays an important role in human physiological functions, mainly in the formation of teeth and bones, the structure of connective tissue and the metabolism of calcium and phosphorus. After a proper amount of fluorine enters the human body, it first penetrates into the teeth and is absorbed by hydroxyapatite in the enamel, forming a hard and dense surface protective layer of fluorapatite. This protective layer makes enamel insoluble under acidic conditions, inhibits the activity of acidophilic bacteria, and prevents the adverse effects of some enzymes on teeth, thus preventing the occurrence of dental caries. It is considered that when the fluorine content in drinking water is lower than 0~0.3 mg/L, if you drink it for a long time, but you can't get proper supplement from food channels, it will cause dental caries, especially the bones of children and the elderly will become brittle and prone to fractures. For this reason, people often add fluoride to the water supply in such areas, so that the fluoride concentration is 0.6~ 1.7 mg/L, and the range of fluoride addition is 1.2~3.4 mg based on the drinking water quantity of 2 liters per person per day. When excessive fluoride is ingested, dental fluorosis and chronic fluorosis will occur, which is a serious disease that harms human beings. It makes people's teeth fall off easily, limbs deform and joints ache all over the body, which seriously affects human health. Therefore, when the fluorine content in these drinking water is too high, measures must be taken to reduce fluorine.
Trace elements are essential to the human body, but a special balance must be maintained in the human body. Once this balance is broken, it will affect health. It is relative that an element is beneficial and harmless to the human body, and the key lies in the right amount. As for how much is the appropriate amount, as well as their physiological functions and structures in the human body, it is worthy of our further study.