脂类.2010预防公共卫生学院营养与食品卫生学系

脂类公共卫生学院营养与食品卫生毛丽1HealthNeedsforWeneedsomefatinourfoodandinourbodiestokeepushealthy.Thisneedisindicatedbythenumberoffunctionsfatperformsinnutrition,bothinourdietsandinouroverallbodymetabolism.2HealthProblemswithOfallthenutrients,fatismostoftenlinkedwithchronicdiseases.Ahighfatdietraisestherisksofheartdisease,diabetes,andobesity.Forthisreason,someconcernaboutlipidsiswarranted.Howmuchfatismoderateinyourown3一、脂类的分类一、脂类的分类甘油三酯脂 磷脂,

99%in 95%in固醇类

1%in

5%in4二、脂类的结构和功能（一）甘油三酯，triglyceridesStructure：1glycerol＋3fatty5 体内甘油triglyceridesinthe 和提Storingandprovidingthebodywithenergy 39.7kJ（9.46kcalB:维持体温正常Thelayeroffatbeneaththeskinhelpskeepthebodywarm(insulatingthebody)C:保护作用Protectingandprop uptheorgansinthebody6D:帮助机体更有效利用碳水化合物和蛋白质 thebodyuseitstwootherenergynutrients—carbohydrateandprotein(sparingprotein)E:机体重要Theveryimportantcompositionofthe7F:内分泌作leptin,TNF-α,IL-6,IL-8,adiponectin,resistin,estrogen(雌激素）,Insulin-likegrowthfactor(IGF),angiotensinogen(血管紧张素),IGFbindingprotein3,plasminogenactivatorinhibitor(PAI,纤维蛋白溶酶原激活因子抑制物)8A:提供能量和必需脂ProvidingbodywithenergyandessentialfattyB:改善食物Improvingthecolor,flavor,tasteandshapeoffoods.9C:增加饱腹Becausedietaryfatcausesthestomachtoemptymoreslowlythaneithercarbohydrateorprotein,itimpartssatietyandsatisfaction.D:提供脂溶性维Tosupplybodywithfat-solublevitaminsandaidintestinalabsorptionofthem.riskofhigh-fat心脏病Heartdisease:Foodsaturatedfat(especially12,14,16carbons)raisesbloodcholesteroldramatically,whichcauses heartattackor肥胖Obesity肥胖:High-fatdiettendtostorebody Cancer:Prostatecancerisastrongassociationwithfat;Breastcancerisalittleornoassociationwithdietfat.反式脂肪酸的危害Riskfromtrans-fattyacids:Theyraise andlowerHDL.分类链长Chainlong-chain(14~24carbonsormore)medium-chain(6~12)short-chain(饱和度saturatedFA(SFA)monounsaturatedFA(MUFA)polyunsaturatedFA(PUFA)双键位置Positionofdouble“n-3orω-“n-6orω-异构体Isomericformscis必需脂肪EssentialfattyacidFattyacidsneededbythebody,butnotmadebyittomeetphysiologicallinoleicacid亚油酸).C18:2,n-αlinolenicacid（α–亚麻酸）C18:3,n-FunctionFunctionofTomaintainthestructuralpartsofcellmembranes.(itisapartofphospholipids)是合 素（prostaglandins）的前Lowerbloodcholesterolandriskofheartattackor（4）参与合成生理活性物质类二十烷（i）tlis(前X，s,yy,dli.Theymodulatecardiovascular,（肺部的）immunereproductive（生殖的）,andsecretoryfunctionsinmanycells.DeficiencyDeficiencyofliver,kidney,nerve,vision,and 花生四烯（arachidicacid，AAC20:4,n-6）二十碳五（eicosapentaenoicacidEPAC20:5,n-3)、（docosahexaenoicacid，DHA；C22:6,n-在体内SynthesizeofMUFAin6去饱碳链延长

linoleicacid(C18:2,n- α-linolenicacid(C18:3,n- 十八碳四烯酸(C18:4,n-5去饱碳链延长

bi-homotypeγ-arachidicacid(AA)

二十碳四烯酸(C20:4,n-eicosapentaenoicacid(EPA)4去饱

二十二碳四烯酸(C22:4,n- 二十二碳五烯酸(C22:5,n- docosahexaenoicacid(C22:6,n-

n-6（1） 少，进而血小板的和黏附能力受到破坏。

n-3（1）（2）降低（3）（4）（5） 氧化产生的较多 是

椰子油的脂肪酸組成成%己酸0.2-辛酸4.5-癸酸4.5-月桂酸45.0-豆蔻酸13.0-棕櫚酸7.0-油酸5.0-亞油酸1.0-硬脂酸1.0- 注 短链脂肪酸（short-chainfatty 生理功提供70.4170.30.6(Trans-fatty使LDLHDL增加冠心病 （三）类脂及其功类脂

分磷酸甘油脑磷脂、肌醇磷脂等。Themostimportantmemberis神经 ）肌醇磷脂（磷脂酰肌醇功能Importantconstituentsofcell Theythusallowfat-solublesubstances,includingvitaminsandhormones,topasseasilyinoroutofcells.作 Asemulsifiersinthebodyorfood 提供能量Tosupplybodywith9kcaloriesper(5)其 功能Health递质乙酰胆碱固醇类 一类含有同样多个环状结构的脂类化合

Asamemultiple–ringwithdifferentsidegroups Cholesterolisthemostimportant. FunctionofCholesterolEssentialtothestructureandfunctionofcells, thecellmembrane(about90%oftotalbody Cholesterolistheoriginalmaterialforsynthesisofmanyvitallyimportantbodycompoundssuchasbile,sexhormones,adrenal（肾上腺）hormone,andvitaminD.HarmfulItformsdeposits(Itformsdeposits(沉积物)inthearterywallswhichleadtoatherosclerosis(动脉粥样硬化adiseasethatcausesheartattacksandstrokes.食物中胆固醇含量(mg,以100g食部计食物含食物含食物含（肥瘦牛鸭（肥猪咸鸭（瘦鸡（均值鲤牛肉（肥瘦鸭（均值青牛肉（瘦鹅海羊肉（肥瘦鸡带羊肉（瘦鸭对猪鹅海牛鸡赤猪鸡蛋乌salivarygland---lipasesalivarygland---lipase（脂肪酶Itplaysasmallroleinfatdigestioninadults,butefficientlydigeststheshort-andmedium-chainfattyacidsofmilkin三、Digestion,absorption,andStomach’sStomach’schurningactionmixesfatwithwaterandacid.Agastriclipasehydrolyzes（水解）averysmallamountoffat.Small ）offatbySmall trappedbyPancreaticlipase（胰脂酶 lipase（肠脂酶

fibersandcarriedoutofthebodywiththefecesReabsorbedintothebloodliverGallbladder（胆囊）Long-chainfattyacids

Glycerol,short-andmedium-chainFattyacidsabsorbeddirectlyintobloodMergeintoMergeintoEasilydiffuse intotheintestinalcellsandreassembled（重新合成）intonewtriglycerides.newtriglycerideswithcholesterol,phospholipids,andproteinarepackedintochylomicrons（乳糜微粒）withintheintestinalcellsAbsorbedintolymph,thenintoblood.Cellsallover bodyremovelipidsfromthechylomicrons astheypassby,andmakethemsmallerandsmaller.Livercellscollectthechylomicronremnantsfromblood,andfirstdismantle（拆除）themthenreassemblethepiecesintonewtriglycerides.(meanwhile,thelivercellaremakingotherlipids)ThelipidsmadeintheliverarepackagedwithproteinsasVLDLandshippedtootherpartsofthebody.BodycellremovetriglyceridesfromVLDL.Aslosetriglycerides,VLDLgathercholesterolfromotherlipoproteinscirculatingthroughthebloodstreamand eLDL.TheLDLcirculatethroughoutthebody,makingtheircontentsavailabletothecellsofallthetissues.ThelivermakesThelivermakesHDLpackagestocarrycholesterolsandphospholipidsfromthecellsbacktotheliverforrecyclingordisposal.HealthBothHDLandLDLcarrycholesterol,butelevatedHDLrepresentcholesterolreturningfromthearteriestotheliverforbreakdownandexcretion.HighLDLcholesterolisassociatedwithahighriskofheartattack,whereashighHDLcholesterolseemstohaveaprotectiveeffect.四、膳食脂肪的营养学1.含不饱和脂肪酸和短链脂肪酸越多的脂肪越容易2.一般植物油中亚油酸和α-亚麻酸含量高于动物3.n-6/n-5.鱼类脂肪，尤其是鱼油中含有丰富的DHA和EPA五、脂类的参考摄入量及食物DRIsandFood1.Food.Animalfatsarethechiefcontributorofsaturatedfattyacids(containabout40%to60%oftotalfatassaturatedfattyacids)2).植物油Plantoilscontainmostlyunsaturatedfattyacids,rangingfrom73%to94%oftotalfat.LinoleicLinoleicAcid(n-leafyvegetablesseedsnutsgrainsvegetableoilcorn玉米,safflower红花soybeancottonseed棉籽sesame芝麻sunflower)meats,orcanbesynthesizedfromlinoleicfats lcanola,soybean,walnut胡桃wheatflxseed亚麻子,NutsandEPA(C20:5)andDHA(n-3)HumanHumanmilk,salmon哈鱼,bluefish,tuna金枪鱼,herring鲱鱼,trout鳟鱼sardines沙丁鱼.ect),orcanbemadefromlinolenic TheCommitteeonDietandHealthofU.S.makesthefollowing Reducetotalfatintaketo30percentorlessofenergyintake.Reducesaturatedfatintaketolessthan10percentofenergyintake.Reducecholesterolintaketolessthan300milligramsdaily.AIsofdietaryfat(percentageoftotaldietaryenergy)%%%%n-6/n-45~8<营养学上重要的脂类主要有甘油三酯、磷脂和固醇是 少必肪P导。磷脂是细胞膜的构成成分，也是体内重要 剂胆固醇是内许多重要活性物质的合成材料。植物固醇VLHH。思考 ：必需脂肪酸n-3和n-6脂肪酸、反式脂肪酸2.3.4.5.简述脂类消化、吸收、转运的过6.7.SaturatedfattyAfattyacidcarryingthe umpossiblenumberofhydrogenatoms—forexample,stearicInasaturatedfattyacideachcarbonisjoinedtothenextbyasinglebond.MonounsaturatedfattyFattyacidsthatwithdoublebonearecalledunsaturatedfattyacids.Withonedoublebonearecalledmonounsaturatedfattyacids.Thesefattyacidsaremostlyfromplantssource--forexample,oleicacid（油酸）,whichisabundantintheoliveoil（橄榄油）.PolyunsaturatedfattyFattyacidsthatwithtwoormoredoublebonearecalledpolyuns