Nutrition, also known as modern western nutrition, is a subject that has been rapidly developed and applied to human physiological health after Mr. Carl Hongbang, who is known as the "father of modern nutrition", first put forward the concept of the relationship between nutrients and human health on 1934, and made the first' vitamin/mineral' human nutritional supplement food by modern scientific and technological means. Mr. Carl Hongbang came to China in the early 20th century, got in touch with China's food culture, benefited from the magical concept of Chinese medicine, returned to the United States after studying and studying in China 12 years, and put forward and founded modern western nutrition. Therefore, it can be said that China's diet culture, Chinese medicine culture and health preservation are the ancestors of modern nutrition. China had the concept of nutrition for a long time. For example, China's jiaozi's raw materials and cooking methods conform to China's food culture with color, fragrance and taste while ensuring complete nutrients. This shows that China culture is profound. [Edit this paragraph] Nutrition concept Nutrition is a science about the nature, distribution and metabolism of food and the consequences of insufficient food intake. Nutrients are chemicals that can be absorbed by food and used to improve health. Some nutrients are necessary because they cannot be synthesized by the body, so they must be obtained from food. Essential nutrients include vitamins, inorganic salts and amino acids. Fatty acids and some carbohydrates are used as energy sources. Non-essential nutrients refer to nutrients that the body can synthesize from other chemicals, although they can also be obtained from diet. General nutrients are divided into macronutrients and micronutrients. The English word Nutrition is defined as: ● An organic process in which an organism absorbs and uses food and liquid to maintain its normal function, growth and self-maintenance. Study on the relationship between diet and health and disease. A concept and idea of pursuing the best combination of nutrients and all foods to achieve the best performance of the body. Macro-nutrients Macro-nutrients constitute the main part of the diet, providing energy and growth, as well as essential nutrients needed to maintain life activities. Carbohydrate, fat (including essential fatty acids), protein, inorganic salts and water are macro nutrients. Carbohydrates are converted into glucose and other monosaccharides; Fat is converted into fatty acids and glycerol; Protein is converted into peptides and amino acids. These macronutrients are mutually convertible energy sources. Fat produces 9 kcal/g of heat; Protein/carbohydrate produces 4 kilocalories/gram, and ethanol is usually not used as a nutrient, but 7 kilocalories/gram. Carbohydrates and fats can preserve tissue proteins. If dietary sources or tissue storage (especially fat) can't provide enough non-protein energy, protein can't be effectively used for tissue maintenance, renewal or growth. Therefore, more dietary protein is needed to maintain the positive nitrogen balance. Essential amino acids (EAA) are an integral part of protein and must be provided through diet. Of the 20 amino acids that make up protein, 9 are essential, that is, they must be obtained from diet. Because they can't be synthesized by the body, eight amino acids are necessary for everyone. In addition, babies also need histidine. In the recommended daily dietary allowance (RDA), protein reduced from 2.2g/kg for three-month-old infants to 1.2g/kg for five-year-old children and 0.8g/kg for adults. The requirement of dietary protein is positively correlated with the growth rate. However, at different stages of life, the speed of growth is different. EAA requirements reflect the different requirements of protein (table 1- 1). The total EAA requirement of infants (7 15mg/kg/ day) accounts for 32% of the total EAA requirement in protein. 10~ 12 years old children need 23 1mg/kg every day, accounting for 20%; Adults need 86mg/kg daily, accounting for 1 1%. The amino acid composition of different protein is very different. The similarity between the amino acid composition of a protein and animal tissues determines the biological value (BV) of the protein. The amino acid composition of egg protein is exactly the same as that of animal tissue, and its BV is 100. The biological value of animal protein in milk and meat is high (about 90%). However, the protein BV in cereals and vegetables is low (about 40), and some protein, such as gelatin protein, lack tryptophan and valine. BV is 0. The complementarity of different protein in the diet determines the total BV of the diet. Protein's RDA is based on the assumption that the average BV of compound diet is 70. The requirement of essential fatty acid (EFA) is equivalent to 6%~ 10% of fat intake (equivalent to 5~ 10g/d). They include ω-6(n-6) fatty acid-12- dienoic acid), arachidonic acid (cis-eicosapentaenoic acid-5,8, 1 1, 14- tetraenoic acid) and ω-6 (n 17- pentaenoic acid) and DHA (cis docosahexaenoic acid-4,7, 10, 13, 16, 19- hexaenoic acid). EFA must be provided by diet: vegetable oil provides linoleic acid and linolenic acid, and marine fish oil provides EPA and DHA. The body can synthesize arachidonic acid from linolenic acid. Linoleic acid can partially synthesize EPA and DHA, although fish oil is a more effective source. EFA is required for the formation of many eicosanoic acids, including prostaglandin, thromboxane, prostacyclin and leukotriene. Omega-3 fatty acids seem to play a role in reducing the risk of coronary heart disease (see section 202). All the people are educated about polyunsaturated fatty acids (PUFA), but not all PUFA are educated by the whole people. The daily requirements of major elements such as sodium, chlorine, potassium, calcium, phosphorus and magnesium are in grams (table 1-2). Because every energy consumption of 1kcal requires 1ml of water, which is about 2500ml/d [edit this paragraph], micronutrients, vitamins and trace elements are all micronutrients, and vitamins can be divided into water-soluble and fat-soluble categories (table 1-2). Water-soluble vitamins are vitamin C (ascorbic acid) and eight B vitamins-thiamine (vitamin). Riboflavin (vitamin B2), nicotinic acid, pyridoxine (vitamin B6), folic acid, cobalamin (vitamin B 12), biotin and pantothenic acid. Fat-soluble vitamins include retinol (vitamin A), cholecalciferol (vitamin D), α -tocopherol (vitamin E), chlorophyllin and menaquinone (vitamin K). The storage of E and B 12 in vivo is important. The essential trace elements include iron, iodine, fluorine, zinc, chromium, selenium, magnesium, molybdenum and copper. Except for fluorine and chromium, these trace elements are combined with enzymes or hormones needed for metabolism. Fluorine and calcium form a compound (CaF2), which can stabilize the mineral matrix in bones and teeth and prevent dental caries. Except for iron and zinc, these trace elements are combined with enzymes or hormones needed for metabolism. Trace element deficiency is not common in clinic. Other trace elements related to animal nutrition (namely, aluminum, arsenic, boron, cobalt, nickel, silicon and alum) have not been determined, and they are also necessary for human body. All trace elements are toxic at high concentrations, and some elements (arsenic, nickel and chromium) have been considered as the cause of cancer. In the body, lead, cadmium, barium and strontium are toxic. However, gold and silver are inert as components of teeth. [Edit this paragraph] Other dietary ingredients There are as many as 654.38+ 10,000 kinds of chemicals in a person's daily diet (for example, 654.38+0 cups of coffee contain 654.38+0,000 kinds). Only 300 of them can be classified as nutrients, and only 45 are essential nutrients. However, many other substances are beneficial. For example, food additives (such as antioxidants and stabilizers) can improve the production, processing, storage and packaging of food. Trace ingredients (such as spices, condiments, smells, colors, photochemical substances and many other natural products) can improve the appearance, taste and stability of food. Fiber is also good. It exists in many forms (such as cellulose, hemicellulose, pectin and gum). Different dietary fiber components work in different ways. It depends on its structure and solubility. Fiber can improve gastrointestinal motility and help prevent constipation and diverticulosis (see sections 27 and 33). Foods with high soluble fiber content can reduce the increase of postprandial blood sugar. Sometimes it is part of diabetes control measures (see section 13). Vegetables and fruits rich in guar gum and pectin can reduce the plasma cholesterol level by promoting the conversion of liver cholesterol into cholic acid. Some people think that fiber can promote the excretion of carcinogens produced by bacteria in the large intestine. Epidemiological evidence strongly supports that colon cancer is related to low fiber intake. Dietary fiber has beneficial effects on functional bowel disease, acute appendicitis, Crohn's disease, obesity, varicose veins and hemorrhoids, but its mechanism is still unclear. The fiber content in a typical western diet is low (about 12g per day) because the intake of highly refined flour is high and the intake of fruits and vegetables is low. It is generally recommended to eat more cereals, vegetables and fruits and increase the fiber intake to 30g per day. [Edit this paragraph] The goal of proper diet is to achieve and maintain the ideal body composition. And give full play to the potential of physical and intellectual work. The daily dietary requirements of essential nutrients (including energy sources) depend on age, sex, height, weight, metabolism and physical activity. The National Academy of Sciences/National Research Council's Food and Nutrition Committee and the United States Department of Agriculture regularly review the scientific literature on human needs of 45 essential nutrients. The Food and Nutrition Committee publishes the recommended daily dietary allowance (RDA) every five years. This supply can meet the needs of all healthy people and has a significant safety factor (table 1-3). As little is known about vitamins and minerals, it is estimated that the daily dietary intake is safe and appropriate. In order to be healthy, body composition must be kept within a reasonable range. This requires a balance between energy intake and consumption. If energy intake exceeds consumption or consumption decreases, weight will increase. Can lead to obesity. On the contrary, if the energy intake is lower than the consumption, the weight will be reduced. Standard height and weight (table 1-5) and body mass index are often used to evaluate the ideal composition of the body. Body mass index is equal to weight (kg) divided by the square of height (m). In order to get enough nutrition, people eat a lot of food every day. The whole process in which the human body continuously ingests food from the outside, digests, absorbs, metabolizes and utilizes substances (nutrients or nutrients) needed by the human body in food to maintain life activities. ● RDA = recommended nutrient intake per day ● SDA = maximum safe intake per day ● Free radicals: harmful compounds produced in the oxidation reaction of the body, which have strong oxidation and can damage tissues and cells of the body, thus causing chronic diseases and aging. ● Antioxidant: It is a substance that can help capture and neutralize free radicals, thus eliminating the harm of free radicals to human body. Such as vitamins a, c, e, selenium, zinc, copper and manganese. [Edit this paragraph] Open nutrition information Even in recent years like the 1960s, doctors will still tell patients that nutrition has little to do with health. Now we have another understanding: "You are what you eat!" "Initially, the USDA proposed four basic food categories (dairy products, meat and vegetables rich in protein, cereals and bread, fruits and vegetables) as guidelines for a balanced diet. 1992, the U.S. department of agriculture put forward the food guidance pyramid as a guide to a balanced diet (figure 1- 1). In the pyramid, the intake of cereals was increased (from 4 servings to 6~ 1 1 serving), and fruits and vegetables were divided into two groups (2~4 servings and 3~5 servings respectively), while the intake of milk and meat products remained unchanged (2~3 servings), and a group of fats, oils and sweeteners (marked as "restricted use") was added. Recommended. This amount can range from1600 to 2400 kcal/day. The new food guidelines suggest that the intake of fat should be reduced to 30% of the total energy, and the intake of fruits, vegetables and grains should be increased. The purpose is to provide necessary nutrition as part of a healthy diet. In order to achieve this goal, the Department of Health and Human Sciences of the United States Department of Agriculture put forward a nutrition guide as a supplement to the food pyramid. [Edit this paragraph] Nutrition branch ● Sports nutrition ● Sports nutrition ● Plant nutrition ● Nursing nutrition [Edit this paragraph] Development and application of nutrition The physiological nutrition and health concept of modern nutrition is gradually influencing and changing the life and diet of people who need health. There is no doubt that its development and application and its role and influence on the future society are immeasurable for the time being, but it must be enormous. However, the development and application of nutrition should be compatible with the level of social and economic development. In the final analysis, nutrition is just the westernization of health preservation in the field of health. Nowadays, nutrition is not human nutrition in the full sense, and its development and perfection need to combine new scientific elements.