What are nutrients? What are the major categories of nutrients divided by modern nutrition? How many kinds are there?
Nutrition: It is the process that human beings ingest food from the outside to meet their own physiological needs. The comprehensive process of digestion, absorption and metabolism of food in the body, promoting the growth and development of the body, improving intelligence and strengthening the body, preventing aging and prolonging life is called nutrition.
Nutrients refer to chemical components in food that can provide energy, body composition, tissue repair and physiological regulation.
Nutrients are divided into several categories: protein, fat, sugar, inorganic salts, vitamins, water and dietary fiber.
Types of protein: Classification of food protein: 1) Complete protein 2) Semi-complete protein 3) Incomplete protein.
(1) Classification by composition 65,438+0. Simple protein II. Combined with protein. Simple protein can be divided into albumin, globulin, glutenin, gliadin, protamine, histone and sclerosing protein according to its physical and chemical properties and sources. Binding proteins can be divided into nucleoprotein, phosphoprotein, metalloprotein, chromoprotein and so on according to their auxiliary groups.
(2) According to the molecular shape, there are globular proteins and fibrous proteins.
(3) Classification by structure: 1. Monomer protein 2. Oligomeric protein 3. Polyprotein.
(4) Classification by function: active protein and inactive protein.
Types of fat: saturated fat and unsaturated fat are the most important.
According to structural components: triglycerides, phospholipids and sterols.
According to sources: milk fat, vegetable fat, animal fat, microbial fat.
According to the degree of unsaturation in the structure: drying oil, semi-drying oil and Asia-Africa drying oil.
Types of sugar: According to the number of structural units of sugar, it can be divided into: (1) monosaccharide: sugar that cannot be hydrolyzed into smaller molecules. (2) Oligosaccharide: 2-6 monosaccharide molecules are dehydrated and condensed, and disaccharide is the most common and significant. (3) Polysaccharide: homogeneous polysaccharide: starch, glycogen, cellulose, hemicellulose, chitin (chitin) heterogeneous polysaccharide: glycosaminoglycan (hyaluronic acid, chondroitin sulfate, dermatan sulfate, etc. (4) bound sugars (complex carbohydrates, glycoconjugates): glycolipids, glycoproteins (proteoglycans) and sugars-.
Types of inorganic salts: macroelements and microelements,
Vitamins: fat-soluble and oil-soluble.
Water: bound water, free water
Dietary fiber: Generally, it can be divided into soluble fiber and insoluble fiber according to their water solubility.
Insoluble fiber: cellulose, partially hemicellulose lignin (1ignin).
Soluble fiber: pectin, gum, viscose and some hemicellulose.
What are nutritional value and nutritional density? What are the similarities and differences between them?
The nutritional value of food refers to the degree to which nutrients in food can meet human needs.
Nutritional density refers to the concentration of important nutrients (V, minerals, Pro) in food based on unit calories.
Similarities and differences: both are factors to measure whether food is nutritious. The difference is that the nutritional value of food depends on whether the types and quantities of nutrients in food are complete, whether the proportion is appropriate, and whether it is easy to be digested and absorbed. Different foods have different nutritional values because of their different nutritional components.
What is nutritional balance? Reasonable nutrition? Reasonable diet?
Nutritional balance: the nutrition provided by diet (heat energy and nutrients) is exactly the same as the nutrition needed by human body, that is, the nutrition consumed by human body is in balance with the nutrition obtained from food, which is called nutritional balance.
Reasonable nutrition: refers to the reasonable selection and collocation of food, reasonable storage and addition under the premise of hygiene.
The variety, quantity and proportion of nutrients in food can meet the actual needs of people's physiology, life and labor. Its core is that nutrients should be "comprehensive, balanced and moderate".
A reasonable diet means that the nutrients contained in the diet are not only complete in variety and quantity, but also appropriate in proportion, so that you can eat enough.
It is necessary not only to meet the physiological needs of the body, but also to avoid malnutrition caused by improper proportion of nutrients in the diet or even lack or excess of some nutrients.
What indicators does DRIS include? What do they mean?
1, recommended energy intake:
Energy demand refers to the energy needed to maintain the normal physiological function of the body, that is, to maintain a good health for a long time.
Individuals with good health, body shape, body composition and activity level can achieve energy balance and be competent for energy intake required for necessary economic and social activities.
2. Food sources of energy:
Sugar, fat and protein are common in all kinds of foods, but animal foods are generally more important than plant foods.
There is a lot of fat and protein. Sugar and protein are the main plant foods, and oil crops are rich in fat. Among them, soybean contains a lot of oil and protein. As for fruits and vegetables, they generally contain less energy, except hard fruits, such as walnuts and peanuts, which contain more oil and have high heat energy.
What is nutrition? What is its research content?
Nutrition is a science that studies food and human health, and also studies how to make human beings in the most economical conditions.
Besides obtaining the most reasonable nutrition, it mainly includes the following contents:
1, basic knowledge of nutrition: discuss the normal energy demand of human body and a sample.
2. People's nutrition and diet problems under different physiological conditions and special environment.
3. Nutrition and disease prevention.
4. Ways to improve people's nutritional level.
5. Nutritional problems in food processing and storage and new food development.
Try to analyze the factors that affect human energy demand or consumption.
1, energy required to maintain basal metabolism:
1) basal metabolic rate
2) Factors affecting basal metabolic energy consumption: including body surface area and body shape, age and physiological status, gender factors, race, nutritional status, diseases and endocrine.
2, the energy consumption of physical activity:
3. Special dynamic function of food energy consumption:
4. Growth and development: Growing organisms need extra energy to maintain their growth.
5, the human body's energy demand
What are essential amino acids? Including those? What role do they play in the rational utilization of protein?
Essential amino acids: protein of human body consists of more than 20 kinds of amino acids, of which 8 kinds are not synthesized by human body, but are necessary to maintain nitrogen balance of the body and must be supplied by food, which is called essential amino acids.
Include leucine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. Although histidine can be synthesized in vivo, it is too slow to meet the needs of the body and can also be included.
Know what role they play in the rational utilization of protein: When people ingest protein, essential amino acids are indispensable. And from food intake, the variety should be complete.
Protein's Victory (Physiological) Function?
1. Materials for tissue growth, renewal and repair
2. Participate in the synthesis of enzymes, hormones and some vitamins.
3. Adjust body fluids and acid-base balance
4. Supply of heat energy: When the energy supply of carbohydrate or fat is insufficient, or the intake of protein exceeds the need of protein renewal in the body, protein is also a source of heat energy.
5, enhance immunity
6, maintain the normal function of the nervous system
7. Control of genetic information
8, transportation function:
9, participate in the coagulation process, to prevent excessive bleeding after trauma.
10, muscle contraction
What is the first restrictive amino acid? Biological price? Amino acid score?
Definition of the first restrictive amino acid: The most lacking amino acid in restrictive amino acids will seriously affect the utilization rate of protein and determine the quality of protein.
Biological valence: It is a biological method to evaluate the nutritional value of protein, which refers to the percentage of retained nitrogen to absorbed nitrogen.
Amino acid score: usually refers to the ratio of the first restrictive AA in protein to the corresponding AA in the ideal AA mode, which is regarded as protein's AAS.
5. Analyze the factors that affect the utilization effect of protein in vivo?
1, digestibility: The absorption efficiency of amino acids in protein is very high for most animals, but not for many protein plants.
2. Unbalanced amino acid composition: When a single amino acid or amino acid mixture is added to the diet, which reduces the utilization rate of dietary protein, a certain type of amino acid imbalance will occur. When the intake of protein is low, even if the concentration of some amino acids increases slightly, the demand for other amino acids will increase.
3. Insufficient energy intake: protein alone, without sugar, cannot be used to build and repair tissues. If the heat energy supply is sufficient, the utilization effect of protein in the body is mainly determined by the demand and quality of protein. To make full use of protein's supplementary diet, it is necessary to take in proper calories to ensure it. In order to save protein, you need to consume 50- 100g digestible carbohydrates every day.
4. Vitamins and minerals: Any essential minerals and vitamins required for normal growth and metabolism will affect the utilization of dietary protein. When vitamins and minerals are reduced to a certain extent, it will lead to the decrease of substances in the body.
5. Non-essential amino acid nitrogen: Non-essential amino acids are still the main part of protein molecule. If the ratio of essential amino acids to total nitrogen in food is too high, it will be used as the nitrogen source of non-essential amino acids.
6. Food processing: Heating and using chemicals during processing will affect the availability of amino acids.
7, less physical activity: people who often engage in physical activity are muscular. The same individual, who is not engaged in physical activity for a long time, will relax his muscles and increase his body fat under the condition of constant weight.
8. Injury: Nitrogen excretion will increase after injury. People who eat a normal diet can lose as much as 20g of nitrogen every day.
9. Emotional fluctuation: Abnormal mental stress such as anxiety, fear and anger increases adrenal hormone secretion, accelerates glycogen decomposition, and promotes fat oxidation and protein decomposition.
Analysis on the harm of amino acid imbalance to human body and its remedial measures
1) positive nitrogen balance: nitrogen intake >: nitrogen excretion. Pro synthesis speed in human tissues >: If you lose speed, human tissues will increase. It is found in growing children and adolescents, pregnant women and lactating mothers, and convalescence after illness. , and should maintain a positive nitrogen balance.
2) Negative nitrogen balance: nitrogen intake.
3) Nitrogen balance: the discrepancy is consistent. It is considered that this person is in a state of nitrogen balance, and the intake of protein can just repair and renew human tissues, but human tissues have not increased or grown.
Excretion nitrogen = urine nitrogen (urea, ammonia, uric acid and creatinine)+fecal nitrogen (nitrogen in intestinal secretions and exfoliated cells is excreted with feces)+skin excretion nitrogen (nitrogen-containing substances such as epidermal cells, hair and secretions are partially lost on the body surface).
What are the physiological functions of seven fats?
1, providing energy: 2, providing essential fatty acids:
3. Cells that make up body tissues: Phospholipids are components that make up cell membrane, outer membrane of nerve myelin sheath and nerve cells. Sterol is an essential substance for the production of steroid hormones in the body. Lipids are the basic raw materials of cell structure.
4. Carriers of fat-soluble vitamins and help their absorption and utilization:
What are the eight essential amino acids? Physiological function? What are the important fatty acids?
Leucine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine
Physiological functions: (1) promote the growth and development of the body, and repair tissues and cells;
(2) provide nutrition for the body;
(3) regulating the secretion of various enzymes and hormones in the body;
(4) improve the immune resistance of the body;
(5) transport other nutrients and detoxify;
(6) therapeutic effect.
Important fatty acids: potential fatty acids: fatty acids that are necessary for the normal growth of mammals but cannot be synthesized by animals, such as linoleic acid and linolenic acid.
What aspects should we pay attention to when commenting on the nutritional value of lipids?
1, digestibility of edible fat: closely related to its melting point. The digestibility and absorption rate of oil directly indicate the utilization rate of oil, and the utilization rate of oil with high digestibility and rapid absorption rate is high.
2. Stability of oil: If the oil is left in the air for a long time or deteriorated and rancid due to unfavorable factors, it will not only have peculiar smell, but also reduce its nutritional value. Because the vitamins and fatty acids are destroyed, the calorific value is reduced, and even toxic substances are produced, it is inedible.
3. Types and contents of fatty acids and vitamins
What are the physiological functions of 10 available sugar?
1, energy supply
2. Anti-ketogenic effect
Step 3 Save protein
4. Protect the liver and enhance liver function.
Step 5 set up an organization
Step 6 provide dietary fiber
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