Vitamin A: It is fat-soluble, and its main function on human body is to maintain the growth of various epithelial cells, promote the regeneration of rhodopsin, prevent night blindness and keratomalacia, and enhance the resistance to infectious diseases. The epithelial cells of the elderly are easily damaged and their resistance is relatively low. Therefore, it is necessary to supplement vitamin A properly. In addition to getting some from the diet (such as carrots, animal livers, dark vegetables, eggs and milk), you can also take vitamin A capsules, 1 time a day, 1 capsule each time, with a content of 25,000 international units, intermittently. Vitamin E: It is fat-soluble, also called "tocopherol". Its main function on human body is to eliminate free radicals, resist oxidation and remove "lipid peroxide" and "lipofuscin" in the body, thus delaying the aging process of the body. Animal experiments have proved that vitamin E can prolong the average life span of animals and reduce the incidence of cancer. It leads to the increase of lipid peroxidation, obvious lipofuscin deposition, aggravated biofilm damage and muscle atrophy and thinning. Therefore, vitamin e should be supplemented. In addition to dietary intake (widely found in green plants, especially in various natural vegetable oils), oral vitamin E capsules, with a daily dose of more than 400 mg, may cause blurred vision, diarrhea, fatigue and other side effects, and should be avoided. Vitamin C: water-soluble, also known as "ascorbic acid". The effect on human body is complicated, mainly to maintain the normal functions of blood vessels, muscles, bones, teeth and other organs. In particular, it can enhance the elasticity of capillaries and prevent bleeding, so it is called ascorbic acid. It can also increase the body's resistance to various infectious diseases, promote wound healing and accelerate the formation of connective tissue. For the elderly, it is of great significance to take vitamin C to increase their resistance to various infections. At the same time, keep blood vessels, especially capillaries in all parts healthy and prevent bleeding. It has special health care value for the elderly. Vitamin C tablets are not only taken from food (widely found in various fresh fruits and vegetables), but also can be taken orally, three times a day, 1-2 tablets each time (the content of each tablet is 100 mg), which can be taken for a long time and generally has no side effects. Vitamin B 1: also known as thiamine, soluble in water, can prevent beriberi (especially peripheral neuritis caused by vitamin B 1 deficiency, not beriberi or athlete's foot), stimulate appetite, nourish nerves and improve muscle function. Taking vitamin B 1 plays an important role in rehabilitation when the elderly have poor appetite, symptoms of peripheral neuritis or indigestion. Vitamin B 1 is widely found in coarse grains such as cereals, wheat and soybeans. If the elderly eat refined white rice and flour for a long time, they may lack vitamin B 1. Oral supplement, three times a day, 2 tablets each time, the content of each tablet is 10 mg, which can be taken for a long time or intermittently. In addition to the above four vitamins, other vitamins are generally not lacking, unless there are special diseases, a special vitamin can be considered (for example, anemia patients should use vitamin B 12, bleeding patients should supplement vitamin K, etc. However, vitamin A, vitamin E, vitamin C and vitamin B 1 are the most valuable supplements for health care and prevention. Of course, for the duration and dosage, it is best to consult the doctor concerned. Vitamins, also known as vitamins, are indispensable nutrients for the human body. They were named "life-sustaining nutrients" by Polish scientist Fink. Vitamins are essential nutrients to maintain human health. They are essentially low molecular weight organic compounds. They can't be synthesized in the body, or the amount of synthesis is difficult to meet the needs of the body, and they must be supplied by food. The daily demand for vitamins is very small (usually measured in milligrams or micrograms). They are neither raw materials for body tissues nor energy-supplying substances in the body. However, they play an important role in regulating substance metabolism, promoting growth and maintaining physiological functions. If a vitamin is lacking for a long time, it will lead to various diseases. There are many kinds of vitamins, which are usually divided into fat-soluble vitamins and water-soluble vitamins according to solubility. The former contains A, D, E and K, is insoluble in water, soluble in fat and lipid solvents, coexists with lipids in food, and is closely related to lipid absorption during intestinal absorption. When lipid is poorly absorbed, such as biliary obstruction or long-term diarrhea, its absorption is greatly reduced, and even can cause deficiency. The simplest example is like the well-known truth that carrots eat oil. The excretion efficiency of fat-soluble vitamins is low, and excessive intake will accumulate in the body, which will have harmful effects and even poisoning. Water-soluble vitamins include vitamin C ascorbate (B 1, B2, B6, B 12, PP, etc.) in B vitamins. B vitamins are a component of coenzyme. B6, pantothenic acid and biotin in B vitamins are widely found in food and can be synthesized by intestinal bacteria. No typical defects were found in humans. Water-soluble vitamins are characterized by being soluble in water and insoluble in fat and organic solvents. It is easy to excrete from urine, with high excretion efficiency, and generally does not produce accumulation and toxic effects. Vitamins are essential organic compounds in human metabolism. The human body is like an extremely complex chemical plant, constantly carrying out various biochemical reactions. This reaction is closely related to the catalysis of enzyme. Coenzymes must participate in the activities of enzymes. It is known that many vitamins are coenzymes of enzymes or constituent molecules of coenzymes. Therefore, vitamins are important substances to maintain and regulate the normal metabolism of the body. It can be considered that vitamins exist in human tissues in the form of "bioactive substances". Most vitamins can't be synthesized in the human body, or the synthetic amount is not enough to meet the needs of the human body. Therefore, it must be taken from food. The vitamin content in food is less, and the human body needs little, but it is an indispensable substance. If there is a lack of vitamins in the diet, it will cause metabolic disorder and cause vitamin deficiency. If vitamin A is lacking, there will be night blindness, dry eyes and dry skin; Lack of vitamin d can cause rickets; Lack of vitamin B 1 can cause beriberi; Lack of vitamin B2 can lead to cheilitis, angular stomatitis, glossitis and bursitis; Lack of PP can cause boils; Lack of vitamin B 12 will lead to pernicious anemia; Lack of vitamin c can lead to scurvy. Vitamins are a huge family, and there are dozens of known vitamins, which can be roughly divided into fat-soluble and water-soluble. The former includes vitamins A, D, E and K, while the latter includes vitamins B and C, and there are many "vitamins". At present, the main vitamins found in medicine are: fat-soluble vitamin A. Maintain normal vision and prevent night blindness; Maintain the health of epithelial cells; Promote growth and development; Enhance resistance to infectious diseases; Prevention and treatment of dry eye. Vitamin D regulates calcium and phosphorus metabolism, promotes absorption and utilization, and promotes bone growth. Vitamin E. Maintain normal reproductive capacity and normal muscle metabolism; Maintain the integrity of the central nervous system and vascular system. Vitamin k stops bleeding. It is not only the main component of prothrombin, but also can promote the production of prothrombin in the liver. Water-soluble vitamin B 1 in children with vitamin k deficiency. Maintain the normal functions of circulation, digestion, nerves and muscles; Regulating gastrointestinal function; Coenzymes forming decarboxylase participate in sugar metabolism; It can prevent beriberi. Vitamin B2. Also known as riboflavin. Nucleoprotein is a component of many important coenzymes in the body. These enzymes can transfer hydrogen during the metabolism of substances in the body, and are also essential substances for the metabolism, energy utilization and composition of protein, sugar and fatty acids. Can promote growth and development, and protect eye and skin health. Pantothenic acid (calcium pantothenate). Anti-stress, anti-cold, anti-infection, prevent the toxicity of some antibiotics, and eliminate postoperative abdominal distension. Vitamin B6. It plays an important role in protein metabolism. Treat neurasthenia, vertigo, atherosclerosis, etc. Vitamin B 12. Anti-fatty liver, promote liver to store vitamin A; Promote cell development and maturation and body metabolism; Treat pernicious anemia. Vitamin B 13 (lactic acid clear). Vitamin B 15 (pantothenic acid). It is mainly used to resist fatty liver and improve the oxygen metabolism rate of tissues. Sometimes used to treat coronary heart disease and chronic alcoholism. Vitamin B 17. Highly toxic. Some people think it can control and prevent cancer. P-aminobenzoic acid. Among the B vitamins, it is one of the newly discovered vitamins. Can be synthesized in the human body. Inositol. One of the B vitamins, like choline, is a lipophilic vitamin. Vitamin C. Structure connecting bones, teeth and connective tissue; It has adhesion to capillary wall cells; Increase antibodies and enhance resistance; Promote red blood cell maturation. Vitamin P. Vitamin PP (nicotinic acid) plays the role of transferring hydrogen in the process of cell physiological oxidation and has the role of preventing and treating furuncle. Folic acid (vitamin m). Antianemia; Maintain the normal growth of cells and the function of immune system. Vitamin T helps blood coagulation and platelet formation. Vitamin u. It plays an important role in treating ulcers. Vitamins are organic compounds necessary for human nutrition and growth. If the body lacks vitamins, there will be some kind of disease. Therefore, some people think that vitamins are nutrients, and the more intake, the better. The more vitamins people need, the better? The answer is no, and the key to reasonable nutrition lies in "appropriate amount". Excessive intake of certain vitamins is not only useless, but also harmful to the body. As we know, vitamins can be roughly divided into water-soluble (vitamins B and C) and fat-soluble (vitamins A, D, K, etc. ). Excess water-soluble vitamins can generally be excreted with urine, while excess fat-soluble vitamins A or D cannot be excreted. This gives people the impression that it is harmless to eat more water-soluble vitamins. Some people advocate taking 3-5 grams of vitamin C orally every day to achieve the purpose of health care. In fact, this is harmful. Experiments have confirmed that taking vitamin C 1 g for a long time can cause oxaluria, hyperuricemia and hypervolemia. Some people may have a rash, edema, blood pressure drop and nausea all over the body. Among fat-soluble vitamins, the poisoning caused by excessive vitamin A and vitamin D is the most common. Excessive vitamin A can cause insomnia, asthma, dizziness, alopecia, nausea and diarrhea. Excessive vitamin D can lead to loss of appetite, burnout, constipation, weight loss and low fever. Normal people need vitamin C 50- 100 mg, vitamin A 2500-3000 international units and vitamin D 300-400 international units every day. In terms of nutrition, the so-called vitamins should be a kind of substances that the human body can't synthesize (or the amount of synthesis can't meet the needs), which is indispensable for normal metabolic process and physiological function adjustment. They are nutrients that must be provided by food. Therefore, when it is lacking, some typical clinical symptoms will appear. So far, we have not found any deficiency caused by amygdalin deficiency, so these two substances can not be called vitamins at all. Vitamins B 15 and B 17 are food ingredients beneficial to human health, which are called vitamins, but they have not been recognized by scholars all over the world so far. Recent studies show that vitamins have some special functions, such as the emotional regulation of pantothenic acid, folic acid and vitamin B 12 to reduce DNA loss, and the benefits of folic acid plus B6 to the cardiovascular system. For vitamin supplements, we should supplement them from two aspects: diet and vitamin preparations. The vitamin content of fruits and vegetables is very high, but because the vitamin content of each vegetable and fruit is different, it may not be able to supplement all aspects of vitamins in a balanced way. Vegetables and fruits also lose vitamins during processing and cooking, so vitamin preparations can play a balancing role. However, vitamin preparations are not easy to absorb and are not natural and green, so fruits and vegetables are mainly used as supplements.