味精安全問題課件

Umami/MSG:SafetyIssues

味精的安全問題JohnD.Fernstrom,Ph.D.Professor-UniversityofPittsburghSchoolofMedicine匹茲堡大學(xué)醫(yī)學(xué)院教授ScientificAdvisor-IGTCIGTC科學(xué)顧問Outline內(nèi)容綱要Briefreviewoforiginalissuesleadingtoexpressionofconcerninearly1970s

簡要回顧上世紀(jì)70年代初引起關(guān)注的安全問題Briefsummaryofsafetyviewsnow

簡單總結(jié)當(dāng)前關(guān)于味精安全的觀點(diǎn)Examinationoftwogeneralissues兩大類問題Neurotoxicity神經(jīng)毒性GeneralAdverseEffects(e.g.,MSGSymptomComplex)所有不良反應(yīng)（如味精綜合癥）Conclusions

結(jié)論KwokRHM

Chinese-RestaurantSyndrome中國餐館綜合癥

NewEnglJMed

278:796,1968(letter)

1968年新英格蘭醫(yī)學(xué)雜志（通訊）FirstreportofadversesymptomsinhumansassociatedwiththeingestionofChinesefoodthatsuggestedapossiblelinktoMSG(aswellasmanyotheringredients).首例報(bào)道人體攝入中國食品后出現(xiàn)不適癥狀可能與所添加的味精有關(guān)（也可能是其他添加成分）Ananecdotalcase-report.單例報(bào)告（缺乏足夠科學(xué)依據(jù)）SchaumbergHHetal.

MonosodiumL-Glutamate:ItsPharmacology&RoleintheChineseRestaurantSyndrome

Science163:826-828,1969

谷氨酸單鈉的藥理學(xué)及其在中國餐館并發(fā)癥中的角色

《科學(xué)》163期，826-828頁，1969DefinedMSG"SymptomTriad“味精“三種并發(fā)癥狀”表現(xiàn)為Burning灼燒感FacialPressure面部緊張ChestPain胸痛Skeletalstunting骨萎縮Markedobesity明顯肥胖Sterility不育Hypothalamiclesions下丘腦損傷MSGINJECTED注射味精后OlneyJW.

BrainLesions,ObesityandOtherDisturbancesinMiceTreatedwithMonosodiumGlutamate.

SCIENCE164:719-721,1969.

小白鼠注射味精后出現(xiàn)大腦損傷，肥胖以及其他系統(tǒng)紊亂

1969年科學(xué)雜志ConventionalToxicologicdatabaseforreviewbyJECFAwasveryextensive,includingacute,subchronic&chronictoxicitystudiesinrats,mice&dogs,togetherwithstudiesonreproductivetoxicityandteratology供食品添加劑聯(lián)合專家委員會(huì)審查的常規(guī)毒性數(shù)據(jù)資料非常完整，包括大白鼠、小白鼠和狗的急性，亞慢性，慢性毒性研究以及遺傳性毒性和畸形學(xué)研究。TheSafetyEvaluationofMonosodiumGlutamateWalkerR,LupienJRJournalofNutrition130:1049S-1052S,2000.味精的安全評(píng)估2000年?duì)I養(yǎng)學(xué)雜志Neurotoxicity神經(jīng)毒性研究DietaryMSG食用味精

Plasma(GLU)血漿（谷氨酸）上升

Brain(GLU)大腦（谷氨酸）上升

Neuronalexcitation&death神經(jīng)興奮和死亡BarrierstoNeurotoxicity

GastrointestinalTractefficientlyusesingestedGLU(MSG)asE-source(95+%).胃腸道能有效地吸收95%以上的谷氨酸鈉作為能源GutisthusabarriertoGLUentryintoblood.腸道因此能阻止谷氨酸進(jìn)入血液中Blood-BrainBarrierpreventsGLUpenetrationintobrain.血腦屏障阻止谷氨酸滲透到大腦OnlyveryhighoraldosesofMSGbygavagecanraiseplasmaGLUenoughtogetGLUintobrain只有灌喂大劑量的味精，才會(huì)致血漿中的谷氨酸含量升高，而進(jìn)入到大腦MSGinfood

doesnothavethiseffect.食物中添加的味精不會(huì)有這種效果FernstromJDetal.JClinEndocrinolMetab

81:184-191,1996.1996年，臨床內(nèi)分泌代謝雜志Adultmales(80kg)quicklyingestedMSG,12.7g(150mg/kg)

insolution.成年男子（體重約80公斤）能很快吸收溶液中12.7g（約150毫克每公斤）的味精TsaiP-J,HuangP-CMetabolism48:1455-1460,1999.Arrows=mealorsnack箭頭代表攝取的食物或點(diǎn)心Meals:0745,1215,1800h飲食時(shí)間：0745，1215，1800DailyMSGdose=100mg/kg:每日攝入味精量：100mg/kgBreakfast:15mg/kg早餐：15mg/kgLunch:40mg/kg午餐:40mg/kgDinner45mg/kg晚餐：45mg/kgDataaremeans±sem(n=10)數(shù)據(jù)：均值±標(biāo)準(zhǔn)差Blackcircle:noMSG黑圈表示不含味精Whitecircle:MSG.白圈表示含有味精

GLUinjectionipstimulatesPRLsecretioninratsDoesGLU(MSG)ingestionstimulatePRLsecretioninhumans?腹腔注射谷氨酸鈉會(huì)刺激小白鼠催乳素的分泌，它會(huì)對(duì)人體產(chǎn)生同樣的作用嗎？12.7goralloadofMSGinmalesubjects雄性研究對(duì)象12.7克口服PlasmaPRLinratsinjectedwithMSG(1000mg/kgip).From:TerryLCetal.BrainResearch217:129-142,1981.RatsHumansPlacentalBarriertoMaternalGlutamate胎盤屏障母體中的谷氨酸鈉SteginkLDetalAmJObstetGynecol122:70-78(1975)Monkeystudy.猴子實(shí)驗(yàn)Highestdose(400mg/kgiv,opencircles)producedplasmaGLU70-timesnormal.BattagliaFC.JNutrition

130:974S-977S(2000)EffectoforalMSGloadingonbreastmilkfreeGLUconcentrationsinlactatingwomen哺乳婦女食用味精后母乳不會(huì)有谷氨酸鈉Lactatingwomeningested100mg/kgMSGincapsuleswithwater,andmilksamplesweretakenattheindicatedtimesthereafter.ThisdoseraisedplasmaGLUfrom45nmol/mltopeakvaluesofabout300nmol/mlin30-45min.From:BakerGLetal.,Factorsinfluencingdicarboxylicaminoacidcontentofhumanmilk.In:GlutamicAcid:AdvancesinBiochemistry&Physiology,FilerLJetal.,ed.NewYork,RavenPress,1979,pp.111-123.哺乳期女性加水?dāng)z入100mg/kg的膠囊，對(duì)其后特定時(shí)間的母乳樣品進(jìn)行檢驗(yàn)表明：這一劑量使得血液谷氨酸濃度在30-45分鐘內(nèi)從45nmol/ml提高到峰值約300nmol/ml。From:BakerGLetal.,Factorsinfluencingdicarboxylicaminoacidcontentofhumanmilk.In:GlutamicAcid:AdvancesinBiochemistry&Physiology,FilerLJetal.,ed.NewYork,RavenPress,1979,pp.111-123.影響人體母乳二氨基酸濃度的因素谷氨酸：生物化學(xué)和生理學(xué)進(jìn)展BrainIssues大腦問題

RelevancetohumanMSGingestion:有關(guān)人體攝入味精TheplacentablocksGLUtransferfrommaternalintofetalblood:FETALbrainissafe.胎盤會(huì)阻止谷氨酸從母體傳遞給胎兒：胎兒大腦不會(huì)受到影響B(tài)reastmilk(GLU)doesnotrisewhenmotheringestshigh-doseMSG:NEWBORN/INFANTbrainissafe.當(dāng)母體攝入大劑量的味精母乳中的谷氨酸含量不會(huì)上升：新生兒的腦發(fā)育是安全的InfantmetabolizesGLUatsamerateasadult(Steginketal.,PediatricRes20:53-58,1986).嬰幼兒具有和成年人同樣的谷氨酸代謝的能力BrainIssues大腦問題

Thehumanbrainisunaffectedbytheveryhighplasma(GLU)followinghighdoseMSGintake攝入大量的味精導(dǎo)致的血漿中高谷氨酸含量不會(huì)對(duì)人體大腦產(chǎn)生影響NodoseofMSGhasyetbeengiventohumanshighenoughtoinduceCNSeffects.至今亦未發(fā)現(xiàn)食用味精會(huì)影響人體中樞神經(jīng)系統(tǒng)CRS/Allergy

(MSGSymptomComplex)中國餐館綜合癥/過敏癥味精綜合癥StudyingMSGSymptomComplex

味精綜合癥研究Canreproduciblesymptomsbedefined?能定義這些重復(fù)性的癥狀么？Arereproduciblesymptomsdose-related?這些重復(fù)性癥狀與攝入劑量有關(guān)嗎?DoMSG-sensitiveindividualsexist?對(duì)味精敏感的個(gè)體存在嗎？SYMPTOMSATTRIBUTEDTOMSG:味精所致癥狀Burning,tightness,numbnessinupperchest,neckandface.發(fā)燒，身體發(fā)緊，胸腔上部發(fā)悶，脖子、面部發(fā)麻Dizziness,headache眩暈，頭疼Chestpain,palpitation胸口痛，心悸Weakness乏力Nausea,vomiting反胃嘔吐Bronchospasm(asthmatics)哮喘Hives(urticaria)麻疹MECHANISMSUNKNOWN機(jī)制未知Multicenter,double-blind,placebo-controlled,multiple-challengeevaluationofreportedreactionstomonosodiumglutamate.GehaRSetal.JAllergyClinImmunol

106:973-80,2000味精反應(yīng)的多中心、雙盲、安慰劑控制、多重治療評(píng)估報(bào)告2000年過敏與臨床免疫學(xué)雜志ProtocolA:

130self-styledMSG-sensitiveindividuals.Fasted, challengeblindwithplaceboorMSG(5ginliquid).實(shí)驗(yàn)A：130例自認(rèn)為MSG過敏者，禁食，以安慰劑或MSG(5克液體)進(jìn)行盲試。ProtocolB: Subjectshadpositiveresponseof≥2symptomsto

eitherorbothtreatmentsinA(i.e.,placeboresponders too).Fast,blindchallengewith0,1.25,2.5or5g MSG(inliquid).實(shí)驗(yàn)B:對(duì)A中，出現(xiàn)陽性反應(yīng)的實(shí)驗(yàn)對(duì)象，超過2種癥狀（例如：對(duì)安慰劑反應(yīng)也一樣）。禁食，以0，1.25，2.5或5克MSG(液體)進(jìn)行盲試。GehaRSetal.,JAllergyClinImmunol

106:973-80,2000ProtocolC: Subjectshadpositiveresponseof≥2symptomsto5 gMSGbutnotplaceboinAorB.Fast,placebo(suc- rose)orMSG(5g),incapsules(blind).Dotwice.實(shí)驗(yàn)C:對(duì)A和B中陽性反應(yīng)的實(shí)驗(yàn)對(duì)象-對(duì)5克MSG出現(xiàn)超過2種癥狀（對(duì)安慰劑沒有），禁食，以膠囊性的安慰劑（蔗糖）或MSG(5克)，進(jìn)行盲試。重復(fù)實(shí)驗(yàn)。ProtocolD: SubjectshadpositiveresponsetobothMSGchal- lengesinC.Fast,breakfast&placebo(sucrose) orMSG(5g),incapsules(blind).Dothreetimes.實(shí)驗(yàn)D:對(duì)C中MSG治療出現(xiàn)陽性反應(yīng)的實(shí)驗(yàn)對(duì)象，禁食，早餐加膠囊性安慰劑（蔗糖）或MSG(5克)，進(jìn)行盲試。重復(fù)3次實(shí)驗(yàn)GehaRSetal.,JAllergyClinImmunol

106:973-80,2000SYMPTOMSRATED:癥狀表現(xiàn)GeneralWeakness虛弱MuscleTightness肌肉緊張MuscleTwitching肌肉酸痛Flushing臉頰發(fā)紅Sweating盜汗BurningSensation灼感Headache-migraine偏頭痛Chestpain胸悶Palpitations心悸Numbness-Tingling發(fā)麻GehaRSetal.,JAllergyClinImmunol

106:973-80,2000ProtocolAResults:實(shí)驗(yàn)A結(jié)果n=50:≥2symptomswithMSG&0/1withplacebo.

MSG組超過2種癥狀出現(xiàn)+安慰劑組1個(gè)n=19:≥2symptomswithMSG&

placebo.超過2種癥狀出現(xiàn)，味精和安慰劑n=17:≥2symptomswithplacebo&0/1withMSG.安慰劑組超過2種癥狀出現(xiàn)+MSG組1個(gè)n=44:0or1symptomswithMSG&placebo.

沒有或1種癥狀出現(xiàn)：MSG+安慰劑GehaRSetal.,JAllergyClinImmunol

106:973-80,2000ProtocolBResults:實(shí)驗(yàn)B結(jié)果n=86fromAhad≥2symptomswithatreatment(blinded:placeboorMSG),andincludedinB.69completed.對(duì)2種癥狀進(jìn)行治療（雙盲：安慰劑或MSG）Overnightfast,challengewith0,1.25,2.5or5gMSG.禁食過夜，按0，1.25，2.5或5克MSG看結(jié)果GehaRSetal.,JAllergyClinImmunol

106:973-80,2000n=19/69reported≥2symptomsto5gMSGbutnotplacebo.19/69例報(bào)道，5克MSG下有超過2種癥狀出現(xiàn)，沒有安慰劑n=14/19thesamesymptomsoccurredinBasinA.14/19例中同樣癥狀出現(xiàn)，類似于A實(shí)驗(yàn)Hence,14/130showedreproducibleresponseto5gMSG.因此，14/130表現(xiàn)出對(duì)5克MSG的可重復(fù)性反應(yīng)ProtocolCResults:實(shí)驗(yàn)C結(jié)果GehaRSetal.,JAllergyClinImmunol

106:973-80,20001995FASEBMSGPanel:

3placebo-MSGchallengesmustgivesamepositiveresponsetoMSG,noresponsetoplacebo.GiveMSGincapsules.1995年美國實(shí)驗(yàn)生物學(xué)聯(lián)合會(huì)味精組：3種安慰劑-味精治療必須引起同樣的對(duì)味精的陽性反應(yīng)，對(duì)安慰劑沒有反應(yīng)，味精應(yīng)該以膠囊的形式給予。n=19had≥2symptomsin

A&B

withMSG&nosymptomswithplacebo.n=12agreedtobestudied.N=19時(shí)，實(shí)驗(yàn)A和B的味精組都有超過2種癥狀出現(xiàn)，安慰劑組沒有癥狀出現(xiàn)，n=12時(shí)，實(shí)驗(yàn)一致。ProtocolCResults:實(shí)驗(yàn)C結(jié)果GehaRSetal.,JAllergyClinImmunol

106:973-80,2000TwoseparatetestsofMSG(5g)vsplacebo.分開測試味精（5克）和安慰劑n=2/12had≥2symptomswithMSG&nonewithplacebo;butsymptomswerenotthesame.n=2/12，味精組超過2種癥狀出現(xiàn)，安慰劑組沒有癥狀出現(xiàn)，但癥狀不同。n=0/130metFASEBcriteriaforMSGsensitivityn=0/130時(shí)符合FASEB的MSG過敏性實(shí)驗(yàn)標(biāo)準(zhǔn)GehaRSetal.,JAllergyClinImmunol

106:973-80,2000CONCLUSION:

Usingcriteriaestablishedbythe1995FASEBpanel,

none

oftheindividualswhoclaimedasensitivitytoMSGactuallyshowedthissensitivitywhentestedunderblindedconditions.結(jié)論：根據(jù)1995年美國實(shí)驗(yàn)生物學(xué)聯(lián)合會(huì)（FASEB）制定的標(biāo)準(zhǔn)，對(duì)那些聲稱味精過敏的個(gè)體進(jìn)行雙盲試驗(yàn)表明他們未表現(xiàn)出敏感性。CRSSymptomsinHumans

人體的MSG癥狀A(yù)sthma:EarlystudiesclaimingthatMSGinducesasthmainasthmapatientshavenotbeenconfirmedinrecentstudiesinvolvinggreaternumbersofpatients.哮喘：早期研究聲稱味精會(huì)導(dǎo)致哮喘病人病情發(fā)作，但近期眾多數(shù)量病人的研究中未得到證實(shí)StevensonDD.Monosodiumglutamateandasthma.JNutr

130:1067S-1073S,2000味精和哮喘2000年?duì)I養(yǎng)學(xué)雜志.MSGSymptomsinHumans

人體的MSG癥狀Urticaria:65subjectswi