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1、 忠告:忠告:食物是最好的医药!食物是最好的医药!第二节第二节 宏量营养素宏量营养素 一、蛋白质一、蛋白质Protein谢惠波谢惠波2014年秋年秋主页目录-Homen n含量:体重含量:体重 16%19%n n更新:更新: 动态平衡,不断更新,每天约动态平衡,不断更新,每天约3%,肠和骨髓最快。,肠和骨髓最快。n n功能:功能: 1. 1.机体构成成分机体构成成分机体构成成分机体构成成分 2. 2.构成各种生理活性物质和重要的生理功能构成各种生理活性物质和重要的生理功能构成各种生理活性物质和重要的生理功能构成各种生理活性物质和重要的生理功能 3. 3.提供热能提供热能提供热能提供热能 人体中
2、蛋白质人体中蛋白质主页目录-Homen n人体组织的构成成分人体组织的构成成分人体组织的构成成分人体组织的构成成分 Required for building and repair of body Required for building and repair of body tissues tissues n n构成各种生理活性物质和重要的生理功能构成各种生理活性物质和重要的生理功能构成各种生理活性物质和重要的生理功能构成各种生理活性物质和重要的生理功能 Enzymes, hormones, and many immune Enzymes, hormones, and many immun
3、e molecules are proteins. Essential body molecules are proteins. Essential body processes such as water balancing, processes such as water balancing, nutrient transport, and muscle nutrient transport, and muscle contractions require protein to function. contractions require protein to function. n n提
4、供热能提供热能提供热能提供热能 Protein is a source of energyProtein is a source of energy。n n肽、氨基酸特有的生理功能肽、氨基酸特有的生理功能肽、氨基酸特有的生理功能肽、氨基酸特有的生理功能 1、 蛋白质功能蛋白质功能Section 1 Functions of protein主页目录-Home2、蛋白质的组成n n主要由碳、氢、氧、硫、氮等。n n有些还有磷、铁、锰、碘、锌等。n n蛋白质是人体中氮的唯一来源。n n大多数蛋白质的含氮量在16%,因此每克n n氮换算成蛋白质是6.25克。3、蛋白质的分类、蛋白质的分类参考蛋白、完全
5、蛋白和蛋白质的互补作用参考蛋白、完全蛋白和蛋白质的互补作用参参 考考 蛋蛋 白白用于测定食物蛋白质质量的标准蛋白。 Reference Protein: A standard against which to measure the quality of other proteins.完完 全全 蛋蛋 白白必需氨基酸模式与人体蛋白质相对一致,能满足机体蛋白质合成需要的食物蛋白质。 Complete Protein: A dietary protein containing all the essential amino acids in relatively the same amounts
6、that human being required. (including animal protein and soy protein ) Incomplete protein蛋蛋 白白 质质 互互 补补 将两种或两种以上的食物蛋白质混合事用,使不同食物中必需氨基酸以多补少,从而提高膳食蛋白质的营养价值。 Complementary Protein: Two or more proteins whose amino acids assortments complement each other in such a way that the essential amino acids miss
7、ing from one are supplied by the other.主页目录-HomeThe first structure 蛋白质(protein) 氨基酸(Amino acid, AA) 非必需AA(nonessential-):9种 半必需AA(条件必需AA):2种 (semi-,or conditionally-)必需AA(essentional-):9种 多肽(poly-)10 AA以上寡肽(oligo-)410 AA以下 3肽(tri-)3AA 2肽(di-)2AA 肽(peptide) 主页目录-Home1. 1. 种类:种类:种类:种类:2020种种种种 (1) (1
8、) 必需必需AAAA(EAAEAA) (2) (2) 非必需氨基酸非必需氨基酸(NEAANEAA) (3) (3) 半必需氨基酸半必需氨基酸 ( semi-EAA or conditional EAA)( semi-EAA or conditional EAA) 半胱酸(半胱酸(CysteineCysteine)蛋氨酸(蛋氨酸(MethionineMethionine) 酪氨酸(酪氨酸(TyrosineTyrosine)苯丙氨酸苯丙氨酸(PhenylalaninePhenylalanine)2. 2. 必需氨基酸:必需氨基酸:必需氨基酸:必需氨基酸: 人体人体不能合成不能合成或或合成速度不能满
9、足机体需要合成速度不能满足机体需要,必需必需从食物中直接获得的从食物中直接获得的AAAA。 Amino acids that the body cannot synthesize in Amino acids that the body cannot synthesize in amount sufficient to meet physiological needs and has amount sufficient to meet physiological needs and has to obtain them from foods. to obtain them from foods
10、. 二、二、 氨基酸和必需氨基酸氨基酸和必需氨基酸 Section 2 Amino acid and EAA主页目录-Home氨基酸氨基酸英文英文氨基酸氨基酸英文英文必需氨基酸必需氨基酸非必需氨基酸非必需氨基酸异亮氨酸异亮氨酸IsoleucineIsoleucine (Ile) (Ile)丙氨酸丙氨酸AlanineAlanine (Ala) (Ala)亮氨酸亮氨酸LeucineLeucine ( (LeuLeu) )精氨酸精氨酸ArginineArginine ( (ArgArg) )赖氨酸赖氨酸Lysine (Lys)Lysine (Lys)天门冬氨酸天门冬氨酸Aspartic acid (
11、ASP)Aspartic acid (ASP)蛋氨酸蛋氨酸MethionineMethionine (Met) (Met)谷氨酸谷氨酸AsparagineAsparagine ( (AsnAsn) )苯丙氨酸苯丙氨酸Phenylalanine (Phenylalanine (PhePhe) )谷氨酰胺谷氨酰胺GlutamicGlutamic acid ( acid (GluGlu) )苏氨酸苏氨酸ThreonineThreonine ( (ThrThr) )甘氨酸甘氨酸GlycineGlycine ( (GlyGly) )色氨酸色氨酸Tryptophan (Tryptophan (TrpTrp
12、) )脯氨酸脯氨酸ProlineProline (Pro) (Pro)缬氨酸缬氨酸ValineValine (Val) (Val)丝氨酸丝氨酸Serine (Ser)Serine (Ser)组氨酸组氨酸* *HistidineHistidine (His) (His)天冬酰胺天冬酰胺AsparagineAsparagine (ASN) (ASN)条件必需氨基酸条件必需氨基酸半胱氨酸半胱氨酸CysteineCysteine ( (CysCys) )酪氨酸酪氨酸Tyrosine (Tyr)Tyrosine (Tyr)表 1-1 人体内的氨基酸*组氨酸为婴儿必需氨基酸,成人需要量可能较少。 摘自Mo
13、dern Nutrition in Health and Disease,第9版,第14页,1999。主页目录-Home氨基酸模式氨基酸模式(AA Pattern)和限制氨基酸和限制氨基酸 (limiting AA)1. 1. 氨基酸模式氨基酸模式氨基酸模式氨基酸模式 (AA Pattern) : 蛋白质中各种必需氨基酸的构成比例。蛋白质中各种必需氨基酸的构成比例。主页目录-Home氨基酸氨基酸人体人体全全鸡蛋鸡蛋牛奶牛奶牛肉牛肉大豆大豆面粉面粉大米大米异亮氨酸异亮氨酸4.04.03.23.23.43.44.44.44.34.33.83.84.04.0亮亮氨酸氨酸7.07.05.15.16.8
14、6.86.86.85.75.76.46.46.36.3赖氨酸赖氨酸5.55.54.14.15.65.67.27.24.94.91.81.82.32.3蛋蛋氨酸氨酸+ +半胱氨酸半胱氨酸3.53.53.43.42.42.43.23.21.21.22.82.82.32.3苯丙氨酸苯丙氨酸+ +酪氨酸酪氨酸6.06.05.55.57.37.36.26.23.23.27.27.23.83.8苏苏氨酸氨酸4.04.02.82.83.13.13.63.62.82.82.52.52.92.9缬氨酸缬氨酸5.05.03.93.94.64.64.64.63.23.23.83.84.84.8色氨酸色氨酸1.01.
15、01.01.01.01.01.01.01.01.01.01.01.01.0表1-2 几种食物和人体蛋白质氨基酸模式数据摘自营养与食品卫生学,第3版,第9页。主页目录-Home限制氨基酸限制氨基酸 (limiting amino acid) 与人体蛋白质模式比较,食物蛋白质中含量相对较与人体蛋白质模式比较,食物蛋白质中含量相对较低的必需低的必需AAAA。 The The essential essential amino amino acid acid found found in in the the shortest shortest supply supply relative relat
16、ive to to the the amount amount needed needed for for protein protein synthesis synthesis in in the the body.body. FourFourAA AA are are mostmostlikelylikelytotobe be limiting: limiting: Lysine Lysine(赖),(赖),MethionineMethionine(蛋),(蛋),ThreonineThreonine(苏),(苏),TryptophanTryptophan(色)(色) . .主页目录-Hom
17、e三、三、 蛋白质的消化、吸收和代谢蛋白质的消化、吸收和代谢 消化和吸收(digestion and absorption) 主页目录-HomeGastric Juice : 1. Acid denaturation 2. 胃蛋白酶Pepsin在小肠进行吸收dietary Protein dipeptide , tripeptide and free AA absorbed through the mucosal cells of small intestine 肽酶peptidase through three active free AA transport systems neutral
18、-,basic- and acidic-. Liver and other organs 主页目录-Home代谢与氮平衡代谢与氮平衡 (metabolism and nitrogen balance)1.代谢代谢摄入蛋白质90克 消 化 道(30%)肌肉(50%)器官体液其它机体蛋白质氨基酸池粪便尿其它(20%)肠道内源性蛋白质70g消化、吸收蛋白质150g图1-1 蛋白质代谢及氮平衡主页目录-Home氮平衡(氮平衡(Nitrogen balance)(1)(1)必要的氮损失(必要的氮损失(必要的氮损失(必要的氮损失(obligatory nitrogen obligatory nitroge
19、n losses losses) (2) (2) 氮平衡:氮平衡:氮平衡:氮平衡: B BI I(U UF FS S)Positive nitrogen balanceN in N outN in = N outNitrogen equillibriumNegativenitrogen balanceN in N out主页目录-Home四、四、 食物蛋白质营养学评价食物蛋白质营养学评价 (一一)蛋白质含量蛋白质含量 (content)(2)表观消化率(表观消化率(apparent -):(二二)蛋白质消化率蛋白质消化率(digestibility)(1)真消化率(真消化率(true -)主页
20、目录-Home( (三三三三) )蛋白质利用率(蛋白质利用率(蛋白质利用率(蛋白质利用率(utilizationutilization)1.Biological value, BV:1.Biological value, BV:生物价生物价生物价生物价 The amount of protein nitrogen that is retained for growth and maintenance,expressed as a percentage of the protein nitrogen that has been digested and absorbed. To determin
21、e the actual value of an absorbed protein as it is used by the body. 主页目录-Home2.2.Amino Acid Score,Amino Acid Score,AASAAS氨基酸评分氨基酸评分氨基酸评分氨基酸评分 The lowest score is 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
22、pattern with that of a reference protein; sometimes called chemical scoring. 主页目录-Home表表1-4 1-4 几种食物和不同人群需要的氨基酸评分模式几种食物和不同人群需要的氨基酸评分模式氨基酸氨基酸人群(人群(mg/g mg/g 蛋白质)蛋白质)1 1岁以下岁以下 2525岁岁 10121012岁岁 成人成人食物食物(mg/g(mg/g蛋白质蛋白质) )鸡蛋鸡蛋 牛奶牛奶 牛肉牛肉组组氨酸氨酸2626191919191616222227273434异亮氨酸异亮氨酸4646282828281313545447474
23、848亮亮氨酸氨酸9393666644441919868695958181赖氨酸赖氨酸6666585844441616707078788989蛋蛋氨酸氨酸+ +半胱氨酸半胱氨酸4242252522221717575733334040苯丙氨酸苯丙氨酸+ +酪氨酸酪氨酸727263632222191993931021028080苏苏氨酸氨酸4343343428289 9474744444646缬氨酸缬氨酸5555353525251313666664645050色氨酸色氨酸171711119 95 5171714141212总计总计4604603393392412411271275125125045
24、04479479摘自WTO Technical Report Series 724,第12页,1985年。主页目录-Home表表1-5 1-5 常见几种食物蛋白质质量常见几种食物蛋白质质量食物食物BVBVUPN(%)UPN(%)PERPERAASAAS全鸡蛋全鸡蛋949484843.923.921.061.06全牛奶全牛奶878782823.093.090.980.98鱼鱼838381814.554.551.001.00牛肉牛肉747473732.302.301.001.00大豆大豆737366662.322.320.630.63精制面粉精制面粉525251510.600.600.340.34
25、大米大米636363632.162.160.590.59土豆土豆676760600.480.48摘自“营养与食品卫生学”,第3版,第11页。主页目录-Home表表1-6 1-6 几种食物蛋白质的几种食物蛋白质的PDCAASPDCAAS食物蛋白食物蛋白PDCAASPDCAAS食物蛋白食物蛋白PDCAASPDCAAS酪蛋白酪蛋白1.001.00斑豆斑豆0.630.63鸡蛋鸡蛋1.001.00燕麦粉燕麦粉0.570.57大豆分离蛋白大豆分离蛋白0.990.99花生粉花生粉0.520.52牛肉牛肉0.920.92小小扁豆扁豆0.520.52豌豆粉豌豆粉0.690.69全麦全麦0.400.40菜豆菜豆0
26、.680.68摘自Understanding Nutrition, 第7版,第215页,1996年。主页目录-Home5、 高蛋白质膳食过多的危害高蛋白质膳食过多的危害problems of excess protein) Adult Bone Loss (Osteoporosis骨质疏松): Calcium excretion rises as protein intake increases. Recommen-dation of calcium-to-protein is more than 20(mg) to 1(g). Cancer: population studies sugge
27、st a correlation between high intakes of animal protein and some type cancer ( cancer of colon, breast,kidneys, pancreas, and prostate) 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.主页目录-Home6、蛋白质供给量和食物来源、蛋白质供给量和食物来源 (DRIs and Food source) 1. 1.RNI: RNI: 1) 1) 数量数量 2 2)质量)质量 ( (优质蛋白质优质蛋白质) )2. 2.Food Source: animal and plant foods. Food Source: animal and plant foods. Milk and Soy beenMilk and Soy been主页目录-Home