The efficacy of vitamins? - Health Preservation Learning Network

The efficacy of vitamins?

vitamin

Vitamins are complex organic substances necessary for biological growth and metabolism. Its effects on human body are different from those of sugar, protein and fat. It can neither provide energy to the body, nor is it a component of the main tissues in the human body. The human body's demand for vitamins is very small, which can only be calculated by milligrams or micrograms. Although the amount is small, it has a great effect. Its physiological function is to control the distribution of nutrients in the body, regulate the physiological function in the body, and as an auxiliary enzyme, promote the smooth progress of various biochemical reactions in the body and promote the growth and development of the human body. Once the human body lacks vitamins, it will cause substance metabolism disorder and cause some diseases. 1498, a Russian expedition consisting of 160 people sailed to India. Due to the lack of vegetables and fruits for a long time during the journey and the lack of vitamins (especially vitamin C) in the body, most people suffer from scurvy and die.

It is known that there are more than 20 kinds of vitamins, which cannot be synthesized by humans and animals themselves and must be taken from plants. The intake of vitamins in the body will not only meet the needs of growth and metabolism, but also store some. Therefore, some animals also contain vitamins. In order to meet people's demand for vitamins, we can not only extract some vitamins from natural raw materials, but also synthesize some vitamins artificially.

Vitamins can be divided into water-soluble and fat-soluble according to solubility. Then, those with similar functions are grouped into one group. When a group contains multiple vitamins, it is marked with numbers such as 1, 2, 3 according to its structure. Fat-soluble vitamins include vitamins A, D, E, K, etc. Water-soluble vitamins include B 1, B2, B6, B 12, vitamin C, vitamin L, vitamin H, vitamin PP, folic acid, pantothenic acid and choline. Because of the complex chemical names of vitamins, common names are widely used in the world. For example, vitamin B 1 is also called thiamine, and vitamin B2 is also called riboflavin.

Some people think that since vitamins are very beneficial to the human body, they should eat more vitamins, which is wrong. Lack of vitamins is not good for human growth and development, and eating more individual vitamins will also affect health. For example, taking too much vitamin D for a long time will cause hypercalcemia, harden soft tissues and easily cause fatigue, headache, polyuria and other diseases. Some vitamins are eaten too much, although they will not endanger health, but they will be decomposed and excreted after absorption, causing waste. Therefore, don't take too many vitamins.

vitamin A

Also known as anti-dry eye alcohol, it belongs to fat-soluble vitamins. The function of vitamin A is to keep the eyesight of eyes in the dark. When you lack vitamin A, you will suffer from night blindness. Vitamin A can promote the normal growth and development of children. Without it, it will lead to the decline of reproductive function, poor bone growth and hindered growth and development. Vitamin A can also maintain the health of epithelial tissue and increase the resistance to infectious diseases. Long-term lack of vitamin A can cause atrophy, keratinization or necrosis of skin and mucosal epithelial cells.

Vitamin A only exists in animal tissues, and it is found in egg yolk, milk, cream, cod liver oil and animal liver. The following table lists foods rich in vitamin A.

Food name

Vitamin a content

(international unit/100g)

Food name

Vitamin a content

(international unit/100g)

pork liver

8700

yolk

3500

chicken liver

50900

duck's egg

1380

Duck liver

8900

milk powder

1400

river crab

5960

cream

2700

Eggs (of hens)

1440

Fresh cream

830

Although plants do not contain vitamin A, the β -carotene contained in them can be converted into vitamin A under the action of carotene enzyme in human and animal liver and intestinal wall. Therefore, eating more carrots, pumpkins, amaranths, spinach, leeks and other red, yellow, green vegetables and fruits containing beta-carotene can also ensure the sufficiency of vitamin A, because both vitamin A and carotene are insoluble in water, but soluble in fat, and taking foods containing vitamin A and beta-carotene together with fat can promote their absorption.

Vitamin B 1

Also known as thiamine or anti-beriberi vitamin. It is a water-soluble vitamin, stable in acidic solution, but easy to decompose in neutral and alkaline solution. The main function of vitamin Bl is to regulate carbohydrate metabolism in the body. If it is lacking, the nervous system that relies on the energy generated by carbohydrate metabolism to maintain its function will be affected first, resulting in symptoms such as polyneuritis, beriberi, lower limb paralysis, edema, and enlarged heart. In addition, vitamin Bl can also promote gastrointestinal peristalsis, enhance digestive function and promote human development.

Vitamin B 1 has two main food sources. First of all, it is rich in the shells and germs of cereals, beans, hard fruits and dry yeast. Therefore, the content of brown rice and bran flour is higher than that of refined rice flour. Second, it is rich in animal viscera (liver and kidney), lean meat and egg yolk. The following table lists the contents of vitamin B 1 in some common foods.

Content of vitamin B 1 in common foods (unit: mg/100g)

Food name

content

Food name

content

Indica rice (brown rice)

0.34

Peanut kernel (raw)

1.07

Indica rice (refined)

0. 15

pork liver

0.40

bread flour

0. 13

pork

0.53

Standard flour

0.46

pig heart

0.34

millet

0.57

yolk

0.27

Corn (yellow and fresh)

0.34

milk

0.04

soybean

0.79

Yeast (dry)

6.56

Because vitamin Bl is easy to decompose in neutral or alkaline solution, when the pH value is greater than 7, heating will decompose most or even all of it. Therefore, vitamin B 1 in foods fried, baked or smoked at high temperature will lose a lot. According to the measurement, the loss of B 1 in bread is 20% ~ 30%. In biscuits and cakes baked with alkaline leavening agent, vitamin B 1 was almost completely destroyed.

vitamin B2

Also known as vitamin G or riboflavin. Whey was first discovered by British chemist Bruce in 1879, and extracted and purified from milk by American chemist Goldberg in 1933. Vitamin B2 is a yellow needle-like crystal, slightly soluble in water, and easily decomposed in alkali and light. Vitamin B2 is phosphorylated into riboflavin phosphate and flavin adenine dinucleotide after entering the human body, and combined with protein to become dehydrogenase for regulating redox process. Dehydroalcohol is an important substance to maintain the respiration of tissues and cells. Without it, the metabolism of substances in the body is disordered, resulting in angular stomatitis, dermatitis, glossitis, seborrheic dermatitis, conjunctivitis and keratitis.

The main food sources of vitamin B2 are internal organs, such as animal liver and kidney, as well as dry yeast, milk, eggs, beans, hard fruits and leafy vegetables. The following table lists foods rich in vitamin B2.

Foods rich in vitamin B2 (mg/ 100g)

Food name

content

Food name

content

pork liver

2. 1 1

cheese

0.50

Pig kidney

1. 1 1

yeast

3.25

chicken liver

1.63

soybean

0.25

eel

0.95

broad bean

0.27

Eggs (of hens)

0.3 1

peanut

0. 14

duck's egg

0.37

sunflower seeds?

0.20

fresh milk

0. 13

Tricholoma (dried)

2.53

milk powder

0.69

basin

2.07

Vitamin B 12

Cobalamin, also known as cobalamin, was discovered by American female scientist Xiao Bo in bovine liver extract of 1947. It is a complex organic compound containing cobalt. Some people call it hematopoietic vitamin because it contains the metal element cobalt. When the human body lacks cobalt, it will cause symptoms such as loss of appetite, pale skin, dizziness and anemia. Vitamin B 12 is involved in the synthesis of nucleic acid, cholic acid and methionine, as well as the metabolism of fat and sugar, which has certain influence on the functions of liver and nervous system. Therefore, vitamin B 12 is not only used to treat anemia, but also used to treat infectious hepatitis and restore the normal function of liver function. Ordinary adults can consume 12 micrograms a day. People who often drink a lot and don't eat dairy products and eggs must take more vitamin B 12.

Vitamin B 12 is stable in neutral solution, easily decomposed in acidic or alkaline solution, and loses its activity in sunlight. Therefore, when processing foods containing B 12, vinegar or alkali cannot be added.

Animal liver, kidney, milk, cheese and eggs contain more vitamin B 12.

vitamin C

Also known as ascorbic acid. 1907 Norwegian chemist holst found it in lemon juice. Pure products are only available in 1934. It is a colorless crystal, which belongs to water-soluble vitamin, easily soluble in water, and its aqueous solution is acidic, so it is called ascorbic acid. It is stable in acidic solution and easy to be oxidized and decomposed in neutral or alkaline solution. Metal ions such as iron and copper can accelerate its oxidation rate.

The main functions of vitamin C in human body are: participating in the redox process in vivo, promoting human growth and development, enhancing human resistance to diseases, promoting the formation of collagen in intercellular substance, maintaining the normal functions of teeth, bones, blood vessels and muscles, and enhancing the detoxification ability of liver. When the human body lacks vitamin C, there will be symptoms such as bleeding gums, loose teeth, fragile bones, easy bleeding of mucous membranes and subcutaneous tissues, and difficult wound healing. In recent years, scientists have also found that vitamin C can prevent nitrite and secondary amine from combining into carcinogen-iminodiamine in the stomach, thus reducing the incidence of cancer.

According to the measurement, adult men need about 65 mg of vitamin C every day, and adult women need about 60 mg of vitamin C every day. Because vitamin C exists in many fresh vegetables and fruits, as long as you eat more vegetables every day, you can meet the needs of the human body. However, we should pay attention to the following problems.

First, because vitamin C is easily soluble in water, fresh vegetables should not be soaked in water for a long time. It should be washed before cutting to avoid the loss of vitamin C.

Second, because copper ions can catalyze the oxidative decomposition of vitamin C, it is necessary to avoid the contact between vegetables and bronzed color during processing.

Third, vitamin C in plants often exists at the same time as vitamin C enzyme. When vitamin C enzyme comes into contact with air, it will promote the oxidation of vitamin C. The higher the temperature, the stronger this effect is. Originally, vitamin C was relatively stable when heated, but it was also destroyed by the action of vitamin C enzyme at high temperature. Therefore, it is best to fry vegetables with fast fire, so that a short period of high temperature is conducive to protecting vitamin C from being destroyed.

There are many foods containing vitamin C, and kiwifruit and pepper are the most abundant. The following table lists the contents of vitamin C in various common animal and plant foods.

Content of Vitamin C in Common Foods (mg/ 100 g)

Food name

content

Food name

content

Kiwifruit (juice)

150~400

pumpkin

4~ 14

pepper

159

cucumber

4~ 12

green pepper

Eighty-nine

shaddock

12.3

bitter gourd

hawthorn

8.9

Chestnuts (raw)

Fresh jujube

5.4

strawberry

Guangdong orange

5.4

white radish

1 1~30

Celery (stem)

6.0

Chinese cabbage

rapeseed

5. 1

wax gourd

A pear growing in Hebei Province

four

cypridopathy

1926 Chemist Carl first extracted from cod liver oil, which is light yellow crystal, insoluble in water and soluble in organic solvents such as ether. Vitamin D is also called sunshine vitamin. Why is it called this name? This is because there is a kind of 7- dehydrocholesterol in human skin, which is converted into vitamin D under the ultraviolet irradiation of the sun. Therefore, often participate in outdoor activities, or sunbathe, the sun will synthesize vitamin D for the human body.

The main elements that make up human bones are calcium and phosphorus, and the absorption of calcium and phosphorus by human body must rely on vitamin D. If vitamin D is lacking in the body, even if there is enough calcium and phosphorus in the diet, the bones will not be calcified normally, making them fragile and prone to bending and deformation, resulting in spiral legs, chicken breasts and rickets under the pressure of the body.

The human body should take about 25 milligrams of vitamin D every day. If it is lacking, it will lead to rickets. However, excessive intake will increase the absorption of calcium in the intestine, so that the soft tissues such as the heart and renal tubules will be calcified, which will cause syndromes such as excessive thirst, fatigue, constipation and hypercalcemia. Therefore, as long as you insist on outdoor activities, you don't need to supplement vitamin D. Cod liver oil is a food containing more vitamin D, and all kinds of fish, egg yolk, milk and liver also contain vitamin D.

tocopherol

It was discovered by American chemist Evans in 1922 and extracted from malt oil, also known as tocopherol. It belongs to fat-soluble vitamins. Because it can promote the secretion of human luteinizing hormone and has anti-infertility activity, it is also called anti-infertility vitamin. It is stable to acid, alkali and heat, and it is not easy to be destroyed by high temperature heating, but it can be destroyed by ultraviolet rays. Sensitive to oxygen, it is easily oxidized to quinones in the air, and it is a natural antioxidant to prevent fatty acids from spoilage. It can prevent the oxidation of unsaturated fatty acids in human body and protect cells from damage. It has obvious effects on preventing arteriosclerosis and cerebral hemorrhage and anti-aging of human body.

A recent article published in an American magazine said that vitamin E can prevent and treat diabetes. Scientists injected diabetic mice with vitamin E, which inhibited the growth of protein called PKC in 90% of the diseased mice. PKC is the "culprit" leading to abnormal blood glucose concentration in human body.

Vitamin E mainly exists in plant foods, and is rich in cottonseed oil, corn oil, peanut oil, sesame oil, spinach, lettuce leaves, sweet potatoes and other foods. The following table lists the content of vitamin E in common foods.

Content of Vitamin E in Common Foods (mg/ 100 mg)

Food name

content

Food name

content

cotton oil

beef liver

1.40

corn oil

carrot

0.45

peanut oil