營養(yǎng)與食品衛(wèi)生學(xué) 02課件

1、 第一篇 營養(yǎng)學(xué)PART 1 NUTRITION 1.營養(yǎng)：是指人體攝取、消化吸收、利用食物中營養(yǎng)物質(zhì)和排除 廢 物的生物學(xué)過程。 It is a biological process which nutrients and functional compositions in the foods are ingested, digested, absorbed, transported ,utilized and the waste are excreted. 2.營養(yǎng)素： (1)定義：食物中可給人體提供能量、機(jī)體構(gòu)成成分和組織修復(fù)以及有生理調(diào)節(jié)功能的化學(xué)成分。 Chemical subst

2、ances obtained from food and used in the body to provide energy,structural materials,and repair of the bodys tissues; Nutrients may also reduce the risk of some diseases.(2) Classification protein lipids macronutrients carbohydrate (dietary fiber) nutrients water vitamin micronutrients macroelements

3、 minerals 核酸 nucleic acid ? microelements 3. 合理營養(yǎng)（Rational Diet） 通過合理的膳食和科學(xué)地烹調(diào)加工，能向機(jī)體提供足夠數(shù)量的熱能和各種營養(yǎng)素，并保證各種營養(yǎng)素之間的數(shù)量平衡，以滿足人體的正常生理需要，并保持人體健康。 Nutrients intakes meet the requirements of the body5.膳食營養(yǎng)供給量(Recommended Dietary Allowance，RDA) 是對各種人群提出的保證人體營養(yǎng)需要的膳食中應(yīng)含有的熱能和營養(yǎng)素的適宜量。 The average daily amount of

4、a nutrient considered adequate to meet the known nutrient needs of practically all healthy people; a goal for dietary intake by individuals.4. 營養(yǎng)生理需要量（Nutritional Requirement） 是指能保持人體健康，達(dá)到應(yīng)有發(fā)育水平和能充分有效地完成各項(xiàng)體力和腦力活動(dòng)所需要的熱能和各種營養(yǎng)素的必需量。 The lowest continuing intake of energy and nutrients that maintain the

5、 specified criterion of adequacy (that will maintain the specific biochemical and physiological functions of the body).Chapter 1 Basic Nutrition 第 一 章 營 養(yǎng) 學(xué) 基 礎(chǔ) 含量-16%19%.更新： 動(dòng)態(tài)平衡，不斷更新，每天約3%，腸和骨髓最快。 Section 1 Protein ( 蛋白質(zhì) )一、蛋白質(zhì)（一）人體中蛋白質(zhì)：（二）功能： 1.機(jī)體構(gòu)成成分 2.構(gòu)成各種生理活性物質(zhì)和重要的生理功能 3.提供熱能 （三）The first stru

6、cture 蛋白質(zhì)(protein) 氨基酸（Amino acid, AA） 非必需AA(nonessential-)：9種 半必需AA（條件必需AA）：2種 （semi-,or conditionally-）必需AA（essentional-）：9種 多肽（poly-）10 AA以上寡肽（oligo-）410 AA以下 3肽（tri-）3AA 2肽（di-）2AA 肽(peptide) 氨基酸英文氨基酸英文必需氨基酸非必需氨基酸異亮氨酸Isoleucine (Ile)丙氨酸Alanine (Ala)亮氨酸Leucine (Leu)精氨酸Arginine (Arg)賴氨酸Lysine (Lys

7、)天門冬氨酸Aspartic acid (ASP)蛋氨酸Methionine (Met)谷氨酸Asparagine (Asn)苯丙氨酸Phenylalanine (Phe)谷氨酰胺Glutamic acid (Glu)蘇氨酸Threonine (Thr)甘氨酸Glycine (Gly)色氨酸Tryptophan (Trp)脯氨酸Proline (Pro)纈氨酸Valine (Val)絲氨酸Serine (Ser)組氨酸*Histidine (His)天冬酰胺Asparagine (ASN)條件必需氨基酸半胱氨酸Cysteine (Cys)酪氨酸Tyrosine (Tyr)表 1-1 人體內(nèi)的氨

8、基酸*組氨酸為嬰兒必需氨基酸，成人需要量可能較少。 摘自Modern Nutrition in Health and Disease,第9版,第14頁,1999。(三) 氨基酸模式(AA Pattern)和限制氨基酸 (limiting AA)1. 氨基酸模式 (AA Pattern) ： 蛋白質(zhì)中各種必需氨基酸的構(gòu)成比例。2.限制氨基酸 （limiting amino acid）： 與人體蛋白質(zhì)模式比較，食物蛋白質(zhì)中含量相對較低的必需AA。 The essential amino acid found in the shortest supply relative to the amount

9、 needed for protein synthesis in the body. FourAA are mostlikelytobe limiting: Lysine，Methionine，Threonine，Tryptophan .3.參考蛋白、完全蛋白和蛋白質(zhì)的互補(bǔ)作用參 考 蛋 白用于測定食物蛋白質(zhì)質(zhì)量的標(biāo)準(zhǔn)蛋白。 Reference Protein: A standard against which to measure the quality of other proteins.完 全 蛋 白必需氨基酸模式與人體蛋白質(zhì)相對一致，能滿足機(jī)體蛋白質(zhì)合成需要的食物蛋白質(zhì)。 Comple

10、te Protein: A dietary protein containing all the essential amino acids in relatively the same amounts that human being required. (including animal protein and soy protein ) Incomplete protein蛋 白 質(zhì) 互 補(bǔ) 將兩種或兩種以上的食物蛋白質(zhì)混合事用，使不同食物中必需氨基酸以多補(bǔ)少，從而提高膳食蛋白質(zhì)的營養(yǎng)價(jià)值。 Complementary Protein: Two or more proteins whos

11、e amino acids assortments complement each other in such a way that the essential amino acids missing from one are supplied by the other.幾種食物混合后蛋白質(zhì)的生物價(jià) 食物BV混 合 比 例小米-6737-31大米57324046大豆6416208豌豆4815-玉米60-40-牛肉（干）76-15混合后生物價(jià)-747389Gastric Juice : 1. Acid denaturation 2. Pepsin- not highly specific but

12、 preferential attack on bonds adjacent to aromatic AA and leucine. 3.Carboxypeptidase-terminal aromatic or branch-chained; arginine or lysine; neutral- dietary Protein Panc- elastase(彈性蛋白酶)- arometic AA reatic trypsin(胰蛋白酶)- NH2- juice chymotrypsine(糜蛋白酶) - lysine, arginine dipeptide , tripeptide an

13、d free AA absorbed through the mucosal cells of small intestine peptidase through three active free AA transport systems neutral-,basic- and acidic-. Liver and other organs （二） 代謝與氮平衡(metabolism and nitrogen balance)1.代謝攝入蛋白質(zhì)90克 消 化 道(30%)肌肉(50%)器官體液其它機(jī)體蛋白質(zhì)氨基酸池糞便10g(1.6gN)尿75g(12gN)其它5g(0.8gN)(20%)腸

14、道內(nèi)源性蛋白質(zhì)70g消化、吸收蛋白質(zhì)150g圖1-1 蛋白質(zhì)代謝及氮平衡四、食物蛋白質(zhì)營養(yǎng)學(xué)評價(jià) (1)真消化率（true -）(一)蛋白質(zhì)含量 (content）(2)表觀消化率（apparent -）:(二)蛋白質(zhì)消化率(digestibility)(三)蛋白質(zhì)利用率（utilization）1.Biological value, BV:生物價(jià) The amount of protein nitrogen that is retained for growth and maintenance,expressed as a percentage of the protein nitrogen

15、 that has been digested and absorbed. To determine the actual value of an absorbed protein as it is used by the body. 2.Net Protein Utilization,NPU蛋白質(zhì)凈利用率 The amount of protein nitrogen that is retainedfrom a given amount of protein nitrogen eaten. To determine the amino acid composition anddigestib

16、ility of a test protein. 3.Protein Efficiency Ratio, PER: 蛋白質(zhì)功效比值 A measure of protein quality assessed bydetermining how well a given protein supportsweight gain in growing rats. Used to establish the protein quality for infantformulas and baby foods.4.Amino Acid Score,AAS氨基酸評分 The lowest score is

17、the score of limiting AA which is the AAS of the protein. A method of evaluating protein quality by comparing a test proteins amino acid pattern with that of a reference protein; sometimes called chemical scoring. 表1-4 幾種食物和不同人群需要的氨基酸評分模式氨基酸人群（mg/g 蛋白質(zhì)）1歲以下 25歲 1012歲 成人食物(mg/g蛋白質(zhì))雞蛋 牛奶 牛肉組氨酸26191916

18、222734異亮氨酸46282813544748亮氨酸93664419869581賴氨酸66584416707889蛋氨酸+半胱氨酸42252217573340苯丙氨酸+酪氨酸726322199310280蘇氨酸4334289474446纈氨酸55352513666450色氨酸171195171412總計(jì)460339241127512504479摘自WTO Technical Report Series 724,第12頁,1985年。5.Protein Digestibility corrected AAS, PDCAAS:（經(jīng)消化率校正的氨基酸評分） A measure of protein

19、 quality assessed bycomparing the amino acid score of a food proteinWith the amino acid requirements of preschool-ageChildren and then correcting for the truedigestibility of the protein; Recommended by the FAO/WHO and used toestablish protein quality of foods for daily valuepercentage on food label

20、s. 表1-6 幾種食物蛋白質(zhì)的PDCAAS食物蛋白PDCAAS食物蛋白PDCAAS酪蛋白1.00斑豆0.63雞蛋1.00燕麥粉0.57大豆分離蛋白0.99花生粉0.52牛肉0.92小扁豆0.52豌豆粉0.69全麥0.40菜豆0.68摘自Understanding Nutrition, 第7版，第215頁，1996年。蛋白質(zhì)營養(yǎng)不良KwashiorkorMarasmusMarasmus Kwashiorkor Infancy(less than 2 yr) older infants and young children(1-3 yr) Develops slowly;chronic PEM

21、rapid onset; acute PEM Severe weight loss some weight loss Severe muscle wasting, with fatSome muscle wasting,with retention of some body fatGrowth:60% weight-for-age growth:60%-80% weight-for-age No detectable edema edemaNo fatty liver enlarged fatty liver Anxiety焦急, apathy淡漠 apathy, misery痛苦, irri

22、tability易怒, sadness Good appetite possible loss of appetite Hair is sparse,thin and dry; Easily pulled out hair is dry and brittle; easily pull out; changes color; becomes straight Skin is dry, thin, and easily wrinkles skin develops lesion3. 高蛋白質(zhì)膳食過多的危害 （problems of excess protein） Adult Bone Loss

23、(Osteoporosis骨質(zhì)疏松): Calcium excretion rises as protein intake increases. Recommen-dation of calcium-to-protein is more than 20(mg) to 1(g). Cancer: population studies suggest a correlation between high intakes of animal protein and some type cancer ( cancer of colon, breast,kidneys, pancreas, and pr

24、ostate) Gain Weight: Protein-rich foods are often fat-rich foods. Others. Heart Disease: Foods rich in animal protein tend tobe rich in saturated fats and cholesterol; homocystei（高半胱氨酸）may be an independent risk factor for heart disease.六、蛋白質(zhì)供給量和食物來源 （DRIs and Food source） RNI: 1) 數(shù)量 2）質(zhì)量 (優(yōu)質(zhì)蛋白質(zhì))Ass

25、essment of protein nutrition in human body (1) Serum albumin: 35-50g/L (2) Serum transferritin: 2.2-4g/L (3) Retinol-binding protein: 26-76mg/L (4) Thyroxine-binding-albumin:280-350mg/L3. Food Source: animal and plant foods. Milk and Soy been中國居民膳食蛋白質(zhì)的推薦攝入量: RNI與RDAAge (year)RNI（2000）RDA（1988）manwom

26、anmanwoman01.53.0g/kg.bw.2.04.0g/kg.bw.0.51353535352404040403454545454505050455555555506555555557606060608656565609656565651070657065RNI與RDA：續(xù)表Age (year)RNI（2000）RDA（1988）manwomanmanwoman11757570807080148580809080輕7565807018中80709080重908010090孕期早+5中+15+15晚+20+25乳 母+20+256075657565Section 2 Lipids (

27、脂類 ) 固醇類,sterols： 脂類甘油三脂,triglycerides：磷脂, phospholipids99% in body, 95% in food99% in body, 95% in food一、脂類的分類 Classification一、脂類的功能 (function) Structure：1 glycerol 3 fatty acids Function （一） triglycerides, 甘油三脂(TG)(1) triglycerides in the body: A: Storing and providing the body with energy: 1g 9.4

28、6kcal (兩個(gè)特點(diǎn)）B: The layer of fat beneath the skin helps keep the body warm ( insulating the body) C: Protecting and propping up the organs in the body D: Helping the body use its two other energy nutrients carbohydrate and protein ( sparing protein )E: The very important composition of the body F: In

29、cretion: leptin, TNF-, IL-6, IL-8, adiponectin, resistin, estrogen, Insulin-like growth factor (IGF), angiotensinogen (血 管緊張素), IGF binding protein 3, plasminogen activator inhibitor (PAI, 纖維蛋白溶酶原激活因子抑制物)(2). Triglycerides in the foods: A: Providing body with energy and essential fatty acid. B: Impr

30、oving the color, flavor, taste and shape of foods. C: Because dietary fat causes the stomach to empty more slowly than either carbohydrate or protein, it imparts satiety and satisfaction.D: To supply body with fat-soluble vitamins and aid intestinal absorption of them. (3). risk of high-fat diet Hea

31、rt disease: Food saturated fat (especially 12, 14, 16 carbons) raises blood cholesterol dramatically, which causes heart attack or stroke. Obesity 肥胖: High-fat diet tend to store body fat efficiently. (3) Cancer: Prostate cancer is a strong association with fat; Breast cancer is a little or no assoc

32、iation with diet fat. (4) Risk from trans-fatty acids: They raise LDL and lower HDL. (二) fatty acids , 脂肪酸 (FA) chain length: long-chain (1014 carbons or more) medium-chain (6 or 8 -) short-chain ( 24 or 26) Saturation（飽和度）: saturated FA (SFA) monounsaturated FA (MUFA) polyunsaturated FA (PUFA) posi

33、tion of double bond: “n” or “” “n-3”: the initial double bond situated between the third and 4th carbon atoms from the methyl end. “n-6”: the initial double bond is between the 6 and 7 isomeric forms 異構(gòu)體: cis 順式 ； trans 反式(1) Classification(2). Essential fatty acid, 必需脂肪酸 (EFA) Definition:Classifica

34、tion: (1) linoleic acid (亞油酸). C 18:2, n-6 (2)- linolenic acid（ 亞麻酸）. C 18:3, n-3 Fatty acids needed by the body , but not made by it to meet physiological needs.Synthesize of MUFA in body linoleic acid (C18:2,n-6) -linolenic acid (C18:3,n-3) 6去飽和酶 -linolenic acid (C18:3,n-6) 十八碳四烯酸 (C18:4,n-3) 碳鏈延長

35、酶 bi-homotype -linolenic 二十碳四烯酸 (C20:4,n-3) acid (C18:3,n-6) 5去飽和酶 arachidic acid (AA) timnodonic acid (EPA) (C20:4,n-6) (C20:5,n-3) 碳鏈延長酶 二十二碳四烯酸 (C22:4,n-6) clupanodonic acid (C22:5,n-3) 4去飽和酶 二十二碳五烯酸 (C22:5,n-6) docosahexenoic acid (DHA) (C22:5,n-3)Function of EFATo maintain the structural parts

36、of cell membranes. (it is a part of phospholipids) Used to synthesize many hormone like substances- eicosanoids（二十烷） : prostaglandins (PG,前列腺 素)，Thromboxane(TXA,凝血惡烷)，leukotrienes (LT, 白三烯 ),hydroxy fatty acids, and lipoxins(脂素). (3) Lower blood cholesterol and risk of heart attack or stroke, especi

37、ally EPA (eicosapentaenoic acid) and DHA (docosahaxaenoic acid). They modulate cardiovascular, pulmonary, immune, reproductive, and secretory functions in many cells.Deficiency of EFAAffect development, production, liver, kidney, nerve, vision, and skin. (三) 磷脂 (phospholipid)1. Structure： It consist

38、 of a glycerol backbone with one or two attached fatty acids, plus a different structure that includes a phosphate group attached to the other hydroxyl group(s).The most important member is lecithins（卵磷脂）. 2. Function (1) Important constituents of cell membranes. They thus allow fat-soluble substanc

39、es, including vitamins and hormones, to pass easily in or out of cells. (3) As emulsifiers （乳化劑）in the body or food manufacturers.(4) To supply body with 9 kcalories per gram. (5) Health function: different points. (四) 固醇 (Sterols) 1. Structure: A same multiple ring with different side groups attach

40、ed. Cholesterol is the most important. 2. Function: Essential to the structure and function of cells, especially the cell membrane (about 90% of total body cholesterol ). Cholesterol is the original material for synthesis of many vitally important body compounds such as bile, sex hormones, adrenal h

41、ormone, and vitamin D.3. Harmful effects: It forms deposits (沉積物) in the artery walls which lead to atherosclerosis (動(dòng)脈粥樣硬化)- a disease that causes heart attacks and strokes. 二、脂類代謝（metabolism） mouth salivary gland（唾液腺）-lipase（脂肪酶）: It plays a small role in digestion in adults, but efficiently diges

42、ts the short- and medium-chain fatty acids of milk in infants. Stomach Stomachs churning 攪拌 action mixes fat with water and acid . A gastric lipase hydrolyzes a very small amount of fat. Small intestine emulsification of fat by bile Pancreatic lipase Intestinal lipase bile trapped by dietary fibers

43、and carried out of the body with the feces Reabsorbed into the blood liver Gallbladder(膽囊) Monoglyceride, fatty acids and glycerol Long-chain fatty acids Monoglycerides Glycerol, short- and medium-chain Fatty acids absorbed directly into blood Merge （結(jié)合）into micelles (微膠粒) Merge （結(jié)合）into micelles (微

44、膠粒) Easily diffuse (擴(kuò)散) into the intestinal cells and reassembled (重新合成) into new triglycerides. With cholesterol and phospholipids, Chylomicrons within the intestinal cells Absorbed into lymph,then into blood Cells all over the body remove lipids from the chylomicrons（乳糜微粒） as they pass by, and mak

45、e them smaller and smaller. protein Liver cells collect the chylomicron remnants（殘?bào)w）, and pack them with lipids , cholesterol and proteins as VLDL which will travel through the body in the blood. HDL made in the liver carry cholesterols and phospholipids from the cells back to the liver. They lose t

46、riglycerides and gather cholesterol fromOther lipoproteins circulating through the bloodstreamAnd become LDLMetabolism of cholesterol三、 Food source and RDA 脂類的食物來源及供給量 1. Food source: 1). Animal fat: plenty of SFA 2). Vegetable oil: plenty of MUFA Linoleic Acid (n-6) leafy vegetables, seeds, nuts, g

47、rains, vegetable oil(corn,safflower 紅花, soybean, cottonseed, sesame芝麻, sunflower) Arachidonic Acid (n-6) meats, can be synthesized from linoleic acid linolenic acid（n-3） fats and oil ( soybean, walnut胡桃, wheat germ) EPA and DHA (n-3) Human milk, shellfish and fish (mackerel 鮐魚, tuna 金槍魚, salmon大麻哈魚,

48、 sturgeon鱘魚, herring鯡魚, trout鱒魚, sardines沙丁魚), can be made from linolenic acid. 2. DRIs: basic principle percentage of total dietary energy ：20%-30% SFA / total dietary energy 10%n-6 / total dietary energy 3%, n-6n-341 Cholesterol 300mg/d3. Substitute of fat 蔗糖聚酯 sucrose polyester, Olestra燕麥素 Ostrim

49、 AIs of dietary fat (percentage of total dietary energy )注1：SFA為飽和脂肪酸；MUFA為單不飽和脂肪酸；PUFA為多不飽和脂肪酸注2：n-6/n-3表示n-6系列不飽和脂肪酸與n-3系列不飽和脂肪酸的比例AgeyearFat%SFA%MUFA%PUFA%n-6/n-3Cholesterolmg045 50410.5354041230354617253046114253010810461182030101010461 30060203068108104160(13.5 W)+487(10.5 W)+596注:W為體重(kg)。摘自Te

50、chnical Report Series724,Geneva,WHO,1985。表1-12 人體24小時(shí)靜息代謝參值(Kcal)年齡(y)40 50 57 64 70 77 84 91 100體重（kg） 男性101813511526164817711876199821212243240118301291144415511658175018571964207122093060134314591540162116911772185319352039 60102711621256135114231526162117161837女性101812341356144115271600168517711

51、85619661830108412311334143715251628173118331966306011771264132513861438149915601621169960101611211195126813311404147815521646摘自Nutrition Science and Application,第二版，第190頁,1997。4. The factors affecting BMR (1) Body surface area: (or lean mass fatty tissue)(2) Gender: male female (3) Age: 2% of declin

52、e per 10 years after age 30 5% of decline per 10 years after age 60 (4) Nutrition state: Low energy intake decreases BMR about 10%-20% (5) Physiological status: Pregnancy increases BMR (6) Body temperature: Fever increases BMR (7) High or low air temperature, hormone system activity, nerve and eatin

53、g too much increase BMR (Adaptive Thermogenesis , 適應(yīng)性生熱作用) (8) Caffeine and tobacco increase BMR (二) Physical Activity The energy needed during physical activity depends on body lean mass, intensity (強(qiáng)度) and time of activity. The energy is about 15%-30% of total energy use in sedentary(久坐的) people.

54、(三) Specific dynamic action (or Thermic Effect of Food, TEF)食物特殊動(dòng)力作用或食物熱效應(yīng) 1. Definition The amount of extra energy used by body during digestion, absorption, metabolism, and storage of energy-yielding nutrients. 2. Energy expenditure 5%-6% of total calorie produced by carbohydrates carbohydrateslip

55、ids 4%-5% of that protein 30% of that mixed food 10% 0f total energy consumed（消耗） 3. The mechanism Energy storage: ATP and fat (2) Sympathetic nervous system activity (交感神經(jīng)系統(tǒng)活動(dòng)) 4. Affecting factors (1) protein-rich food is much higher then others(2) large meals show higher values than normal meals(

56、3) TEF decreases with advancing age. (4) Meal frequency. (一) calculation 三、熱能需要量的確定 Estimating energy requirements 1. calculating the total energy expenditure basal metabolism physical activities specific dynamic action 2. Nutritional survey (or Dietary survey) (二) measuring energy use by body（測量法)1. Direct calorimetry A method of determining a bodys energy use by measuring heat that emanates（散發(fā)） from the body, usually using an Insulated chamber（絕熱倉）2. Indirect calorimetry A method of measuring a bodys energy use by measuring its oxygen uptake (and often carbon dioxide