Diet, also known as "diet", refers to the food and drinks we usually eat. People can get the nutrition and energy they need to maintain their health through diet. Vitamins are essential organic compounds for human nutrition and growth. They exist in all kinds of foods. 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, so they must be taken from food. Vitamins are not raw materials for human body, nor can they provide the energy needed by human body, but they play an important role in the process of human growth, metabolism and development. It plays an important regulatory role in the process of substance metabolism and is also a component of many coenzymes in human body. Although the human body's demand for such substances is minimal, it is essential. Vitamins are a huge family, and there are dozens of known vitamins, which can be roughly divided into fat-soluble and water-soluble. Water-soluble vitamins are absorbed from the intestine and circulated to the tissues needed by the body. Most of the excess vitamins are excreted through urine, and very little is stored in the body. Most fat-soluble vitamins are absorbed by bile salts and reach various organs in the body through the lymphatic system. Fat-soluble vitamins are soluble in nonpolar organic solvents, but insoluble in water. They can be absorbed by the body with fat and stored in the body, with low excretion rate, and a large number of fat-soluble vitamins can be stored in the body. Although the chemical structures and properties of various vitamins are different, they are similar as follows: ① vitamins exist in food in the form of provitamins (vitamin precursors); Vitamins are not components of tissues and cells, do not produce energy, and mainly participate in the regulation of metabolism; (3) Most vitamins can't be synthesized by the body or the synthetic amount is not enough to meet the needs of the body, so they must be obtained from food frequently; (4) The human body's demand for vitamins is very small, and the daily demand is often calculated in milligrams (mg) or micrograms (μg), but once it is lacking, it will cause the corresponding vitamin deficiency and cause harm to human health. 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".

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. Vitamin A is a fat-soluble vitamin. Because people or mammals are prone to dry eye when lacking vitamin A, it is also called anti-dry eye alcohol. Vitamin A can prevent human skin and other tissues from becoming dry. People's eyes need vitamin A to produce a photosensitive substance. People who lack vitamin A have blurred vision in the dark. They may suffer from dry eye and night blindness, leading to infection and blindness. Vitamin B is a water-soluble vitamin, and most of the human body is coenzyme. There are mainly the following types: vitamin B 1, also known as thiamine, which can convert starchy food into energy and help the heart and nervous system run smoothly. Without vitamin B 1, we will feel weak and may suffer from beriberi and neurodermatitis. Vitamin B2 is also called riboflavin. Without it, the human body is prone to stomatitis, dermatitis, microvascular hyperplasia and so on.

Vitamin B 12, an anti-pernicious anemia vitamin, also known as cobalamin, contains the metal element cobalt, which is the only vitamin. Its function is to help red blood cells produce folic acid together. Women taking folic acid during pregnancy can prevent the baby's physical problems. It can resist fatty liver, promote the storage of vitamin A in liver, and promote cell development and maturation and body metabolism. When vitamin B 12 is deficient, pernicious anemia will occur, but the human body needs very little B 12, and the human body needs about 12μg every day. Under normal circumstances, people will not be deficient. There are many kinds of B vitamins, so I won't list them here. There is a vitamin that everyone is familiar with: vitamin C! Vitamin C, also called ascorbic acid, is a water-soluble vitamin, which can treat scurvy and is acidic, so it is called ascorbic acid. The main function of vitamin C is to help the human body complete the oxidation-reduction reaction and improve the sterilization and detoxification ability of the human body. We need vitamin C to maintain strong bones, complete teeth and healthy blood circulation, and to help wounds heal. We store very little vitamin C in our bodies, so we must take it from food every day. If vitamin C is lacking in food, scurvy will occur. Vitamin D is a steroid derivative, which belongs to fat-soluble vitamins. Vitamin D is related to the calcification of animal bones, so it is also called calciferol. It can increase calcium in the blood. Nerve and muscle cells need calcium to maintain normal operation, and so does the growth of strong bones. Because vitamin D can regulate calcium, it is necessary for the normal development of bones and teeth. Especially pregnant women, infants and teenagers. If the amount of vitamin D is insufficient at this time, the calcium and phosphorus in the blood will be lower than normal, and the bones will become soft and deformed. What happens to children is called rickets; It's osteomalacia in pregnant women. Vitamin E, also known as tocopherol, is a fat-soluble vitamin. Vitamin E is easily oxidized, so it can protect other substances that are easily oxidized (such as vitamin A and unsaturated fatty acids) from being destroyed. Vitamin E can resist the invasion of free radicals and prevent myocardial infarction caused by cancer. It promotes men to produce energetic sperm. Without it, neither man nor woman can have children. In severe cases, muscle atrophy and nerve numbness will occur. Vitamin E is a strong antioxidant, and insufficient supply of vitamin E will cause various mental or emotional disorders.

Vitamins are very important to our health. Different vitamins exist in different foods, including wheels, vegetables, fruits, fish, meat, eggs and dairy products. Vitamin A: It exists in animal liver, eggs, dairy products, carrots, pumpkins, bananas, oranges and some green leafy vegetables. Vitamin B 1: in sunflower seeds, peanuts, soybeans, pork and cereals. Vitamin B 6: found in meat, grains, vegetables and nuts. Vitamin B 12: In pigs, beef and mutton, fish, poultry, shellfish and eggs. Vitamin C: lemon, orange, apple, jujube, strawberry, pepper, potato and spinach. Vitamins are found in cod liver oil, eggs, margarine, milk and tuna. Vitamin e: grain germ, vegetable oil and green leaves. Vitamin K: In green leafy vegetables. Even foods containing the same vitamins may have different contents, so it is important to eat a variety of foods every day so that our bodies can get enough multivitamins. Vitamins are closely related to our health, but we must not regard vitamins as "tonics", the more the better, and blindly take vitamin products. Eating fresh vegetables and fruits is the simplest and safest way to supplement vitamins. Never take vitamin health products in large doses for a long time to avoid adverse reactions. I have taken writing as an elective before. Although a lot of content was found online, it was edited by myself. ...