讲授临床营养学第一次课课件.ppt

1、主页目录-Home主页目录-Home主页目录-Home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 that h

2、uman 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 missing from on

3、e are supplied by the other.主页目录-Home 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-Home主页目录-Home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Modern Nutrition in H

4、ealth and Disease,第9版,第14页,1999。主页目录-Home主页目录-Home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主页目录-Home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

5、 mucosal cells of small intestine 肽酶peptidase through three active free AA transport systems neutral-,basic-and acidic-.Liver and other organs 主页目录-Home1.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-HomePositive nitrogen balanceN in N outN in =N ou

6、tNitrogen equillibriumNegativenitrogen balanceN in N out主页目录-Home(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)100%N FoodN)MetabolicN(FecalN FoodTD%100N FoodN FecalN FoodAD(1)真消化率（真消化率（true-）主页目录-Home100N absorbedretained NBV The amount of protein nitrogen that is r

7、etained for growth and maintenance,expressed as a percentage of the protein nitrogen that has been digested and absorbed.To determine the actual value of an absorbed protein as it is used by the body.主页目录-Home100protein referrence in theEAA ofcontent protein test in theEAA theofContent AAS The lowes

8、t 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 pattern with that of a reference protein;sometimes called chemical scoring.主页目录-Home摘自WTO Technical Report Series 724,第12页,1985年。主页目录-Home摘自“营养与食品卫生学”，第3

9、版，第11页。主页目录-Home摘自Understanding Nutrition,第7版，第215页，1996年。主页目录-Home 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 suggest a correlation between high intakes of animal pr

10、otein 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-Home主页目录-Home