Chinese name Nutrition mbth Pinyin GYí ng Y? ng Brief introduction of life activities and biological process of food intake and utilization.
catalogue
The basic concept of 1
2 sources of nutrition
3 nutritional value
4 nutrient absorption
5 Reasonable nutrition
6 List of nutritional components of common foods
Basic concept editing
Nutrition, originally meant to seek health, refers to the intake of nutrients needed by human beings from the outside world to maintain their own growth and development.
The role of. Or the process that the human body obtains and uses the materials and energy necessary for its life activities. Therefore, nutrition represents an action, behavior or biological process [1].
It should be noted that "nutrition" is not the same as food or nutrients. The understanding of the word nutrition in society is not correct enough, and the words are not appropriate, such as "rich nutrition", "rich nutrition" and "with or without nutrition". It is correct to change it to "nutritious" or "nutrient-rich". A person's nutritional status refers to the physical condition related to nutrition, that is, the health status of food ingredients and the utilization status of nutritional ingredients. Can be divided into individuals and groups. Generally, some special nutrients are involved, and sometimes there is a comprehensive evaluation of all nutrients, that is, the overall nutritional status, such as iron, protein and vitamins [1].
Nutrition is a science that studies the effects of food on living things. In its development process, nutrition not only includes the changes of food entering the body, such as participating in biochemical reactions and combining with tissues and cells; It also includes instructing people how to choose food to ensure the normal growth, development and reproduction of the body. Therefore, nutrition not only has biological significance, but also has its social and economic significance [1].
Nutrients are essential food ingredients to maintain normal life activities. The study of nutrients in modern nutrition is mainly aimed at the nutritional needs of people and livestock. Nutrients are divided into protein, lipids, carbohydrates, vitamins, minerals, water and dietary fiber [1].
Nutrition source editing
The source of nutrition is generally nutritious food to meet the special needs of people with abnormal digestion or metabolism.
Or by controlling the intake of food or some nutrients to meet the needs of people with special curative effects. This kind of food is not prepared at will, and it often needs careful calculation and careful observation and test to be determined. In most cases, various nutritious foods can be prepared or combined according to the special nutritional needs of patients with various physiological disorders or the additional nutritional needs of healthy people [1].
Generally speaking, the nutrients contained in nutritious food can be divided into two categories-macronutrients and micronutrients. Macronutrients include protein, fat, carbohydrates and some minerals. They are in great demand every day, constitute the vast majority of food, and provide the energy and material needed for body growth, metabolism and exercise. The demand for micronutrients is very small, ranging from a few milligrams (11000g) to a few micrograms (11000mg), including vitamins and some trace elements, which can catalyze the utilization of macronutrients [1].
Nutritional value editor
Nutritional value usually refers to the relationship between nutrients in a specific food and its quality and quantity, and also refers to the degree to which the types, quantities and mutual ratios of nutrients contained in food can meet the needs of human body [1].
In fact, the nutritional value of food is relative, because: ① Few foods can be classified as full of nutritional value. For example, breast milk or formula milk suitable for babies and essential meals suitable for patients are only a few. ② Most foods have high nutrient content and low nutrient content. For example, cereals are rich in carbohydrates and B vitamins, but the content of protein is low and of poor quality, and the fat content is low; Vegetables and fruits are rich in minerals and vitamins, but low in protein, fat and carbohydrates. (3) Even for the same kind of food, due to different strains, parts, producing areas and maturity, the content of nutritional components varies greatly. For example, apples, red Fuji varieties contain more sugar and less fiber, while autumn Venus varieties contain less sugar and more fiber. In addition, the nutritional value of food should also take into account some anti-nutritional factors in food. For example, vegetables with high oxalic acid content affect the absorption of calcium; Tea with high tannic acid content affects the absorption of iron; There are antitrypsin factors in raw soybean, which affect the digestion and absorption of protein. Cooking and processing of food can improve the nutritional value by eliminating anti-nutritional factors, but it will also cause the loss of nutritional components due to pretreatment and high temperature conditions during processing. If a food contains more nutrients and is easily digested and absorbed, then its nutritional value is higher. For example, the nutritional value of animal protein is higher than that of plants, because the types, contents and proportions of essential amino acids in animal protein are more suitable for human needs [1].
Nutrition absorption editor
The process of food decomposition in the digestive tract is digestion, and the process of food entering the blood and lymph through the digestive tract wall is absorption.
Digestive tract refers to a curved pipe with different thickness from oral cavity to anus, which is about 9 meters long. Including the oral cavity
, pharynx, esophagus, stomach, small intestine (duodenum, jejunum, ileum), large intestine (cecum, colon, rectum) and other parts.
The absorption capacity of different parts of the digestive tract varies greatly. Food is not actually absorbed in the mouth and esophagus; The stomach can absorb ethanol and a small amount of water; The colon can absorb water and salt. Only the small intestine is the main part of absorption. The small intestine is about 5 meters long, which is the longest section of the digestive tract. The intestinal mucosa has annular folds and a large number of villi and microvilli, which makes the small intestine have a huge absorption area (the total absorption area can reach 200~400 square meters); In addition, food stays in the small intestine for a long time, about 3 to 8 hours, so these determine that the small intestine is the main part of absorption [1].
Carbohydrates, fats and protein's digestive products are mostly absorbed in the duodenum and jejunum, and are usually absorbed when they reach the ileum. Ileum is considered as a reserve of absorption function, but it can actively absorb bile salts and various nutrients in VB2 small intestine.
alimentation
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Reasonable nutrition
Refers to comprehensive and balanced nutrition, or provides a balanced diet that reaches the reference intake of dietary nutrients. Because there are great differences in the types and quantities of nutrients contained in various foods, the human body can obtain the required nutrients only by reasonably matching various foods [1].
Reasonable nutrition has the following basic requirements:
(1) The intake of calories and nutrients should meet the requirements. Long-term low intake will produce nutritional deficiency; Too high, it will happen.
Hypertrophic disease [1].
(2) The intake ratio of various nutrients should be appropriate. This includes the proportions of three thermogenic nutrients, thiamine (VB 1), riboflavin (VB2) and nicotinic acid (Vpp), nicotinic acid or VB3, furuncle-resistant vitamins, essential amino acids, saturated unsaturated fatty acids, and various vitamins closely related to metabolism [1].
(3) Reduce the nutrient loss in the cooking process. By improving the technical level of processing and storage, the preservation rate of nutrients is improved, thus improving the nutritional value of food.
(4) Establish a reasonable diet system. Eating regularly can increase appetite and absorption, which is good for health.
(5) The ingested food is harmless to human body. That is, food must not go bad; The pollution of pesticides and harmful chemicals is very low; The added food additives shall meet the specified requirements.
Nutrients include water, protein, carbohydrates, minerals, vitamins and fat.
Protein: Too little supply obviously affects the growth and development speed, biochemical reaction, disease resistance and even malnutrition. In this way, it will not only cause backward growth, but also affect the development of brain cells, resulting in mental retardation.
Cell membrane, nerve tissue and hormone composition of fat body are inseparable from it. Fat also keeps warm and insulated; Support the protection of internal organs, joints and various tissues; Promote the absorption of fat-soluble vitamins.
Carbohydrate: it is the main nutrient that provides energy for life activities.
Vitamins: It plays an important role in maintaining human growth and physiological functions, and can promote the activity of enzymes or be one of coenzymes. Vitamins can be divided into two categories. One is fat-soluble vitamins, including Vit. A, D, E and K can be stored in the body and do not need to be provided daily, but excessive doses can cause poisoning; The other is water-soluble vitamins, including vitamin B and vitamin C, accounting for the majority. They are not stored in the body and need to be provided from food every day, so their metabolism is fast and they are not easy to be poisoned. The other is fat-soluble vitamins, which can be stored in human liver. Vitamins A, D, B, C, E, K, folic acid ... all have their own functions and are indispensable, and can help the human body to play a certain role in resisting the absorption of substances. Therefore, it is especially necessary to provide children with fresh vegetables, fruits, liver and egg yolk, eat coarse grains properly and get more sunshine.
Minerals: although they do not provide energy, they have important physiological functions: ① they constitute the main components of bones; ② Maintain the normal physiological functions of nerves and muscles; ③ the composition of constitutive enzyme; ④ Maintain osmotic pressure and acid-base balance. Mineral deficiency is related to diseases such as calcium deficiency and rickets; Iron deficiency and anemia; Zinc deficiency and backward growth and development; Iodine deficiency, growth retardation and mental retardation should be paid enough attention to.
Water: It is an essential substance to maintain life. The metabolism and physiological activities of human body are inseparable from the participation of boiled water.