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1、1,NUTRITION 营养学,李善姬 营养学教研室 ,教材 1.临床营养学. 主编 张爱珍.第3版.人民卫生出版社 参考书： 1.临床营养学. 主编 焦广宇.第3版. 人民卫生出版社 2. Understanding Nutrition. Ellie Whitney， ninth edition 3. Understanding Normal and Clinical Nutrition. Sharon Rady Rolfes , Eighth Edition 4. Nutrition in Clinical Practice. David L. Katz. Second Edition,P
2、art I Basis of nutrition and food Nutrition Chapter 1 energy Chapter 5 vitamins Chapter 2 proteins Chapter 6 minerals Chapter 3 fats Chapter 7 food Nutrition Chapter 4 carbohydrates Part II Clinical nutrition Chapter 1 hospital diet Chapter 2 nutrition support Chapter 3 dietary planning Chapter 4 ga
3、strointestinal disorders Chapter 5 liver disease Chapter 6 cardiovascular disease Chapter 7 renal disease Chapter 8 endocrine disease Chapter 9 surgical disease,4,作笔记、资料积累 认真听讲、经常学习、复习、积累 观察现实相关生活现象,善于思考 注意身边的病例、活学活用 注意交流、寻找机会 听课纪律、请假？ 考试、考查方式,如何学？,An overview of Nutrition,Welcome to the world of nu
4、trition. Although you may not always have been aware of it, nutrition has played a significant role in your life. And it will continue to affect you in major ways, depending on the foods you select. Although most people realize that food habits affect their health, they often choose food for other r
5、easons. After all, foods bring to the table a variety of pleasures, traditions, and associations as well as nourishment. The challenge, then, is to combine favorite food and fun times with a nutritionally balanced diet .,Nutrients in Food and in Body,Composition of Foods Chemical analysis of a food
6、such as a tomato shows that it is composed primarily of water(95 percent). Most of the solid materials are carbohydrates, lipids and proteins. If you could remove these material, you would find a tiny residue of vitamins, minerals, and other compounds. Water, carbohydrates, lipids, proteins, vitamin
7、s and some of the minerals found in foods are nutrients-substances the body uses for the growth, maintenance, and repair its tissues. Food also contain other compounds as well-fibers, phytochemicals, pigments, additives, alcohols, and others. Some are beneficial, some are neutral, and a few are harm
8、ful.,Composition of the Body A complete chemical analysis of your body would show that it is made of materials similar to those found in foods. A healthy 150-pound body contains about 90 pounds of water and about 20 to 45 pounds of fat, The remaining pounds are mostly protein, carbohydrate, and the
9、major minerals of the bones. Vitamins, other minerals, and incidental extras constitute a fraction of a pound. Carbohydrate, fat, and proteins are sometimes called macronutrients because the body requires them in relatively large amounts (many grams daily). In contrast, vitamins and minerals are mic
10、ronutrients, required only in small amounts （milligrams or micrograms daily).,Essential Nutrients The body can make some nutrients, but it cannot make all of them. Also, it makes some in insufficient quantities to meet its needs and, therefore, must obtain these nutrients from foods, the nutrients t
11、hat foods must supply are essential nutrients; also called indispensable nutrients. About 40 nutrients are currently known to be essential for human beings. When used to refer to nutrients, the word essential means more than just “ necessary”; it means “needed from outside the body”-normally, from f
12、oods.,营养素与主要功能,提供热量,参与构建机体组织,细胞,维持和调节生理功能,导出结论,解释结果,进行研究,建立假设,寻找研究问题,新的 知识,新问题,营养学研究方法 （Nutrition Research）,12,Nutrition Research,14,Nutrition information and misinformation On the net and in the news,Nutrition on the Net Get a question? The internet has an answer. The internet offers endless opport
13、unities to obtain high-quality information, but it also delivers an abundance of incomplete, misleading, or inaccurate information.,15,Nutrition in the News Consumers get much of their nutrition information from television news and magazine reports, which have heightened awareness of how diet influe
14、nces the development of diseases. Consumers benefit from news coverage of nutrition when they learn to make lifestyle changes that will improve their health. Sometimes, however, when magazine articles or television programs report nutrition trends, they mislead consumers and create confusion.,Nutrit
15、ion information and misinformation On the net and in the news,16,How to Determine Whether a Website is Reliable,To determine whether a website offers reliable nutrition information, ask the following questions Who? Who is responsible for the site? Is it staffed by qualified professionals? Look for t
16、he authors names and credentials. Have experts reviewed the content for accuracy.,When? When was the site last updated? Because nutrition is an ever-changing science, sites need to be dated and up-dated frequently. Where ? Where is the information coming from? The three letters following the dot in
17、a web address identify the sites affiliation. Addresses ending in “gov” (government), “edu” (educational institute), and “org” (organization) generally provide reliable information; “com” (commercial) sites represent businesses and, depending on their qualifications and integrity, may or may not off
18、er dependable information.,Why? Why is the site giving you this information? Is the site providing a public service or selling a product? Many commercial sites provide accurate information, but some do not. When money is the prime motivation, be aware that the information may be biased. If you are s
19、atisfied with the answers to all of the questions above, then ask this final question. What ? What is the message, and is it in line with other reliable sources? Information that contradicts common knowledge should be questioned. Many reliable sites provide links to other sites to facilitate your qu
20、est for knowledge, but this provision alone does not guarantee a reputable intention. Be aware that any site can link to any other site without permission.,19,学习营养的重要性,营养学是护理学专业的一门不可缺少的学科，也是现代综合医疗组成部分。 营养治疗在医学康复的中起到重要作用。,20,在增强我国人民体质、预防疾病、保护和提高健康水平等方面起着重要作用。 在各系统常见疾病的营养治疗及康复中起着重要的作用,学习营养的重要性,21,主要目的
21、,通过本课程的教学使学生掌握营养素的生理功能、缺乏症状 食物来源和供给量；了解营养与健康的关系 掌握医院基本膳食、治疗膳食和食谱编制及各系统常见疾病的营养治疗。,22,第一章 热能与营养素,Chapter 1 Energy and Nutrients,23,Energy: the capacity to do work. The energy in food Is chemical energy. The body can convert this chemical energy to mechanical electrical, or heat energy. The energy-yiel
22、ding macronutrients-carbohydrates, fats and proteins, provide primary and alternate sources of energy.,第一节 能 量 (energy),24,焦耳(joule,J)， 千焦耳(kilojoule，kJ) 卡(calorie，cal) 千卡(kilocalorie，kcal) 1cal4.184J 1kJ0.239kcal 1MJ=1000kJ。,Energy Unit,25,Calorie Values of Energy Nutrients,1g Carbohydrate：16.7kJ(4
23、.0kcal) 1g Fat：36.7kJ (9.0kcal) 1g Protein：16.7kJ(4.0kcal) 1g Alcohol：29.3kJ (7.0kcal),26,Energy Expenditure,A person takes in energy from food, on average, spends most of it on basal metabolic activities, some of it on physical activities, and a little on the thermic effect of food 人体的能量消耗主要用于维持基础代
24、谢、满足食物特殊动力作用和体力活动三个方面的需要,Basal metabolism: the energy need to maintain life when a body is at complete digestive, physical, and emotional rest Basal metabolic rate (BMR): the rate of energy use for metabolism under specified conditions: after a 12-hour fast and restful sleep, without any physical ac
25、tivity or emotional excitement, and in a comfortable setting. It is usually expressed as kcalories per kilogram body weight per hour.,Thermic effect of food (TEF): an estimation of the energy required to process food (digest, absorb, transport, metabolize, and store ingested nutrients); also called
26、the specific dynamic effect of food.,Energy Balance,In summary When the energy consumed equals the energy expend, a person is in energy balance and body weight is stable. If more energy is take in than is expended, a person gains weight. If more energy is expended than is taken in, a person lose wei
27、ght .,29,先计算体表面积。按下式计算 男：BEE66.473+13.75 体重(kg)+5.0033 身高(cm)6.755 年龄（岁） 女： BEE 655.0955+9.463 体重(kg)+1.8496 身高(cm)4.6756 年龄（岁）,计算基础代谢能量消耗 (basic energy expenditure，BEE),30,Food energy values can be determined by:,Direct calorimetry, which measures the amount of heat released In direct calorimetry,
28、which measures the amount of oxygen consumed.,31,影响人体热能消耗的因素,(1) 体格的影响 同等体重，瘦高者矮胖者，男性高于女性5%-10%。 (2)不同生理、病理状况的影响 儿童、孕妇高，30岁以上每10年降2%。 (3) 环境条件的影响 炎热、寒冷、过多摄食、精神紧张升高；禁食、少食、饥饿降低。,32,(4) 尼古丁和咖啡因可以刺激基础代谢水平升高 (5) 内分泌 体内许多腺体所分泌的激素，对细胞的代谢起调节作用， 如甲状腺亢进 增高,影响人体热能消耗的因素,33,膳食热能来源与参考摄入量 Sources of energy and rec
29、ommendation,碳水化合物：脂肪 ：蛋白质 =5565% :20%25%:10%15% 成人轻体力活动 男：2400kcal/d; 女：2100kcal/d,34,成人中等体力活动 男：2700kcal/d; 女：2300kcal/d 重体力劳动 男：3200kcal/d; 女：2700kcal/d,膳食热能来源与参考摄入量 Sources of energy and recommendation,35,Health Risks of Overweight,As for excessive body fat, the health risks are so many that it h
30、as been designated a disease-obesity. Among the health risks associated with obesity are diabetes, hypertension, cardiovascular disease, sleep apnea, osteoarthitis, some cancers, gall bladder disease, kidney stones, respiratory problems and complications in pregnancy and surgery.,Kwashiorker氏征,Maras
31、mus 氏征,缺乏皮下脂肪,浮 肿,蛋白质能量营养不良(proteinenergy malnutrition，PEM),能量摄入基本满足而蛋白质严重不足,蛋白质和能量摄入均严重不足,Physical activity can help regulate the appetite, help overweight people lose fat, and help underweight people gain muscle.,2003 Wadsworth, a division of Thomson Learning, Inc. Thomson Learning is a trademark
32、used herein under license.,38,第二节、蛋白质 PROTEIN,39,概述 Introduction,Protein is a vital structural and working substance in all cell-not just muscle cell. To build strength, muscles cell need physical activity and all the nutrients-not just protein,Misconception People who associate meat with protein an
33、d protein with strength may eat steak to build muscles.,Amino acid structure,All amino acids have a carbon (known as the alpha-carbon), with an amino group(NH2), an acid group (COOH), a hydrogen (H), and a side group attached, The side group is a unique chemical structure that differentiates one ami
34、no acid from another.,41,（一） 氨基酸的分类 classification 必须氨基酸 essential amino acid 条件必须氨基酸conditionally essential amino acid 非必需氨基酸 nonessential amino acid,一、氨基酸 amino acid,Essential amino acid There are nine amino acids that human body either cannot make at all or cannot make in sufficient quantity to m
35、eet its needs. These nine amino acids must be supplied by the diet; they are essential. Conditionally Essential Amino acids Sometimes a nonessential amino acid becomes essential under special circumstances. For example, the body normally uses the essential amino acid phenylalanine to make tyrosine (
36、a nonessential amino acid). But if the diet fails to supply enough phenylalanine, or if the body cannot make the conversion for some reason (as happens in the inherited disease phenylketonuria苯丙酮尿症,一种先天性代谢异常)then tyrosine becomes a conditionally essential amino acid.,43,*组氨酸为婴儿必需氨基酸，成人需要量可能较少。 摘自Mod
37、ern Nutrition in Health and Disease ，第9版，第14页，1999年。,构成人体蛋白质的氨基酸,44,Protein Quality 蛋白质品质,The protein quality of the diet determines, in large part, how well children grow and how well adults maintain their health. Put simply, high-quality proteins provide enough of all the essential amino acids nee
38、ded to support the bodys work, and low quality proteins dont. Two factors influence protein quality- the proteins digestibility and its amino acid composition,Digestibility Protein must be digested before they can provide amino acid. Protein digestibility depends on such factors as the proteins sour
39、ce and the other food eaten with it. The digestibility of most animal proteins is high(90 to 99 percent); plant proteins are less digestible(70 to 90 percent for most, but over 90 percent for soy and legume). Amino Acid Composition To make proteins, a cell must have all the needed amino acids availa
40、ble simultaneously. If the diet supplies too little of any essential amino acid, protein synthesis will be limited. An essential amino acid supplied in less than the amount needed to support protein synthesis is called a limiting amino acid (限制氨基酸）.,Reference Protein 参考蛋白 The quality of a food prote
41、in is determined by comparing its amino acid composition with the essential amino acid requirements of preschool age children. Such a standard is called a reference protein. High-Quality Proteins 优质蛋白质 A high-quality protein contains all the essential amino acids in relatively the same amounts and p
42、roportions that human beings require; it may or may not contain all the nonessential amino acid.,Complementary protein 蛋白质互补作用 In general, plant proteins are lower quality than animal proteins, and plants also offer less protein. For this reason, many vegetarians improve the quality of proteins in t
43、heir diets by combining plant-protein foods that have different but complementary amino acid patterns. This strategy yields complementary proteins that together contain all essential amino acids in quantities sufficient to support health. The protein quality of the combination is greater than for ei
44、ther food alone.,48,Roles of Proteins 蛋白质的生理功能,As building materials for growth and maintenance 构成体内各种重要的生理活性物质 As enzymes, as hormones , as regulators for fluid balance, as acid-base regulators, as transporters, as antibodies 供给能量和葡萄糖 As a source of energy and glucose,49,protein digestion, absorpti
45、on and metabolism,蛋白质的消化、吸收、代谢,Protein digestion and absorption,51,蛋白质的吸收,蛋白质胰蛋白酶、糜蛋白酶等多种水解酶的作用下分解成氨基酸和小分子肽，被肠粘膜细胞吸收。 在肠肽酶的作用下，小分子肽进一步分解为氨基酸单体，经门静脉进入肝脏。 有些小分子肽也可以被吸收，主要发生在小肠近端，甚至先于游离氨基酸。 另一方面，小分子肽也可能是食物过敏的原因。,Amino Acid Metabolism,30%-肌肉蛋白 50%-体液、器官蛋白质 20%-白蛋白、血红蛋白,53,利用氨基酸合成的物质,54,氮平衡 nitrogen bala
46、nce,营养学上摄入蛋白质和排除蛋白质之间的关系称氮平衡 B=I-(U+F+S) 零氮平衡zero nitrogen balance 正氮平衡 positive nitrogen balance 负氮平衡 negative nitrogen balance,55,四、食物蛋白质的营养价值评价 Measure of protein quality,评价食物蛋白质的营养价值，对于食品品质的鉴定，新资源开发，指导人群膳食等许多方面都是十分必要的。 各种事物的蛋白质含量、氨基酸模式都不一样，人体对不同蛋白质的消化、吸收和利用程度也存在差异。 营养学上，主要是食物蛋白质含量、消化吸收程度、人体利用程度三
47、方面地评价食品蛋白质的营养价值。,56,（一）蛋白质含量,蛋白质含量不等于质量，但是没有一定的数量，再好的蛋白质其营养价值是有限，所以蛋白质含量是食物蛋白质营养价值的基础。 动物性食物-蛋白质含量20% 植物性食物的蛋白质含量较低，但大豆食品的蛋白质含量较高 使用Kiel-dahl 定氮法,57,不仅反映了蛋白质在消化道内被分解的程度，同时反映了吸收的程度。 氮吸收量 蛋白质消化率= 100% 摄入氮量,(二）蛋白质的消化率 digestibility,58,两种消化率区别,A. 表观消化率（apparent digestibility） 摄入氮-粪氮 = - 100 摄入氮 B. 真消化率（
48、net digestibility） 摄入氮-（粪氮-粪内源氮） 吸收氮 = -100 = - 摄入氮 摄入氮,59,几种食物蛋白质的消化率(%),摘自 WHO Technical Report Series 724, 第119页，1985年。,60,生物价(biological value，BV) 蛋白质净利用率(net protein utilization，NPU) 蛋白质功效比值(protein effciency ratio，PER) 氨基酸评分(amino acid score，AAS),（三）蛋白质利用率,61,吸收氮=食物氮(粪氮粪代谢氮) 储留氮=吸收氮(尿尿内源性氮),生物
49、价(biological value，BV),62,蛋白质净利用率 (net protein utilization，NPU),63,蛋白质功效比值 (protein efficiency ratio，PER),64,氨基酸评分 amino acid score，AAS,氨基酸评分,被测蛋白质每克氮(或蛋白质)中氨基酸量(mg),理想模式或参考蛋白质中每克氮(或蛋白质)中氨基酸量(mg),65,经消化率修正的氨基酸评分,经消化率修正的氨基酸评分 氨基酸评分真消化率,protein digestibility corrected amino acid score, PDCAAS,几种食物蛋白质经消化率修正的氨基酸评分,67,五、食物来源和供给量,成人每天摄入约30g蛋白质就可满足零氮平衡，按0.8g/(kgd)摄入蛋白质为宜，我国推荐摄入量为1.16g/ (kgd)。 成年男女轻体力活动：75g，56g 中体力活