脂類.2010預(yù)防公共衛(wèi)生學(xué)院營(yíng)養(yǎng)與食品衛(wèi)生學(xué)系

脂類公共衛(wèi)生學(xué)院營(yíng)養(yǎng)與食品衛(wèi)生毛麗1HealthNeedsforWeneedsomefatinourfoodandinourbodiestokeepushealthy.Thisneedisindicatedbythenumberoffunctionsfatperformsinnutrition,bothinourdietsandinouroverallbodymetabolism.2HealthProblemswithOfallthenutrients,fatismostoftenlinkedwithchronicdiseases.Ahighfatdietraisestherisksofheartdisease,diabetes,andobesity.Forthisreason,someconcernaboutlipidsiswarranted.Howmuchfatismoderateinyourown3一、脂類的分類一、脂類的分類甘油三酯脂 磷脂,

99%in 95%in固醇類

1%in

5%in4二、脂類的結(jié)構(gòu)和功能（一）甘油三酯，triglyceridesStructure：1glycerol＋3fatty5 體內(nèi)甘油triglyceridesinthe 和提Storingandprovidingthebodywithenergy 39.7kJ（9.46kcalB:維持體溫正常Thelayeroffatbeneaththeskinhelpskeepthebodywarm(insulatingthebody)C:保護(hù)作用Protectingandprop uptheorgansinthebody6D:幫助機(jī)體更有效利用碳水化合物和蛋白質(zhì) thebodyuseitstwootherenergynutrients—carbohydrateandprotein(sparingprotein)E:機(jī)體重要Theveryimportantcompositionofthe7F:內(nèi)分泌作leptin,TNF-α,IL-6,IL-8,adiponectin,resistin,estrogen(雌激素）,Insulin-likegrowthfactor(IGF),angiotensinogen(血管緊張素),IGFbindingprotein3,plasminogenactivatorinhibitor(PAI,纖維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:增加飽腹Becausedietaryfatcausesthestomachtoemptymoreslowlythaneithercarbohydrateorprotein,itimpartssatietyandsatisfaction.D:提供脂溶性維Tosupplybodywithfat-solublevitaminsandaidintestinalabsorptionofthem.riskofhigh-fat心臟病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.分類鏈長(zhǎng)Chainlong-chain(14~24carbonsormore)medium-chain(6~12)short-chain(飽和度saturatedFA(SFA)monounsaturatedFA(MUFA)polyunsaturatedFA(PUFA)雙鍵位置Positionofdouble“n-3orω-“n-6orω-異構(gòu)體Isomericformscis必需脂肪EssentialfattyacidFattyacidsneededbythebody,butnotmadebyittomeetphysiologicallinoleicacid亞油酸).C18:2,n-αlinolenicacid（α–亞麻酸）C18:3,n-FunctionFunctionofTomaintainthestructuralpartsofcellmembranes.(itisapartofphospholipids)是合 素（prostaglandins）的前Lowerbloodcholesterolandriskofheartattackor（4）參與合成生理活性物質(zhì)類二十烷（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-在體內(nèi)SynthesizeofMUFAin6去飽碳鏈延長(zhǎng)

linoleicacid(C18:2,n- α-linolenicacid(C18:3,n- 十八碳四烯酸(C18:4,n-5去飽碳鏈延長(zhǎng)

bi-homotypeγ-arachidicacid(AA)

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

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，進(jìn)而血小板的和黏附能力受到破壞。

n-3（1）（2）降低（3）（4）（5） 氧化產(chǎn)生的較多 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 短鏈脂肪酸（short-chainfatty 生理功提供70.4170.30.6(Trans-fatty使LDLHDL增加冠心病 （三）類脂及其功類脂

分磷酸甘油腦磷脂、肌醇磷脂等。Themostimportantmemberis神經(jīng) ）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遞質(zhì)乙酰膽堿固醇類 一類含有同樣多個(gè)環(huán)狀結(jié)構(gòu)的脂類化合

Asamemultiple–ringwithdifferentsidegroups Cholesterolisthemostimportant. FunctionofCholesterolEssentialtothestructureandfunctionofcells, thecellmembrane(about90%oftotalbody Cholesterolistheoriginalmaterialforsynthesisofmanyvitallyimportantbodycompoundssuchasbile,sexhormones,adrenal（腎上腺）hormone,andvitaminD.HarmfulItformsdeposits(Itformsdeposits(沉積物)inthearterywallswhichleadtoatherosclerosis(動(dòng)脈粥樣硬化adiseasethatcausesheartattacksandstrokes.食物中膽固醇含量(mg,以100g食部計(jì)食物含食物含食物含（肥瘦牛鴨（肥豬咸鴨（瘦雞（均值鯉牛肉（肥瘦鴨（均值青牛肉（瘦鵝海羊肉（肥瘦雞帶羊肉（瘦鴨對(duì)豬鵝海牛雞赤豬雞蛋烏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（腸脂酶

fibersandcarriedoutofthebodywiththefecesReabsorbedintothebloodliverGallbladder（膽囊）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、膳食脂肪的營(yíng)養(yǎng)學(xué)1.含不飽和脂肪酸和短鏈脂肪酸越多的脂肪越容易2.一般植物油中亞油酸和α-亞麻酸含量高于動(dòng)物3.n-6/n-5.魚(yú)類脂肪，尤其是魚(yú)油中含有豐富的DHA和EPA五、脂類的參考攝入量及食物DRIsandFood1.Food.Animalfatsarethechiefcontributorofsaturatedfattyacids(containabout40%to60%oftotalfatassaturatedfattyacids)2).植物油Plantoilscontainmostlyunsaturatedfattyacids,rangingfrom73%to94%oftotalfat.LinoleicLinoleicAcid(n-leafyvegetablesseedsnutsgrainsvegetableoilcorn玉米,safflower紅花soybeancottonseed棉籽sesame芝麻sunflower)meats,orcanbesynthesizedfromlinoleicfats lcanola,soybean,walnut胡桃wheatflxseed亞麻子,NutsandEPA(C20:5)andDHA(n-3)HumanHumanmilk,salmon哈魚(yú),bluefish,tuna金槍魚(yú),herring鯡魚(yú),trout鱒魚(yú)sardines沙丁魚(yú).ect),orcanbemadefromlinolenic TheCommitteeonDietandHealthofU.S.makesthefollowing Reducetotalfatintaketo30percentorlessofenergyintake.Reducesaturatedfatintaketolessthan10percentofenergyintake.Reducecholesterolintaketolessthan300milligramsdaily.AIsofdietaryfat(percentageoftotaldietaryenergy)%%%%n-6/n-45~8<營(yíng)養(yǎng)學(xué)上重要的脂類主要有甘油三酯、磷脂和固醇是 少必肪P導(dǎo)。磷脂是細(xì)胞膜的構(gòu)成成分，也是體內(nèi)重要 劑膽固醇是內(nèi)許多重要活性物質(zhì)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.簡(jiǎn)述脂類消化、吸收、轉(zhuǎn)運(yùn)的過(guò)6.7.SaturatedfattyAfattyacidcarryingthe umpossiblenumberofhydrogenatoms—forexample,stearicInasaturatedfattyacideachcarbonisjoinedtothenextbyasinglebond.MonounsaturatedfattyFattyacidsthatwithdoublebonearecalledunsaturatedfattyacids.Withonedoublebonearecalledmonounsaturatedfattyacids.Thesefattyacidsaremostlyfromplantssource--forexample,oleicacid（油酸）,whichisabundantintheoliveoil（橄欖油）.PolyunsaturatedfattyFattyacidsthatwithtwoormoredoublebonearecalledpolyuns