William Li Can we eat to starve cancer.docx
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William Li Can we eat to starve cancer.docx
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WilliamLiCanweeattostarvecancer
Goodafternoon.There'samedicalrevolutionhappeningallaroundus,andit'sonethat'sgoingtohelpusconquersomeofsociety'smostdreadedconditions,includingcancer.Therevolutioniscalledangiogenesis,andit'sbasedontheprocessthatourbodiesusetogrowbloodvessels.
Sowhyshouldwecareaboutbloodvessels?
Well,thehumanbodyisliterallypackedwiththem:
60,000milesworthinatypicaladult.Endtoend,thatwouldformalinethatwouldcircletheearthtwice.Thesmallestbloodvesselsarecalledcapillaries;we'vegot19billionoftheminourbodies.Andthesearethevesselsoflife,and,asI'llshowyou,theycanalsobethevesselsofdeath.Nowtheremarkablethingaboutbloodvesselsisthattheyhavethisabilitytoadapttowhateverenvironmentthey'regrowingin.Forexample,inthelivertheyformchannelstodetoxifytheblood;inthelungtheylineairsacsforgasexchange;inmuscletheycorkscrewsothatmusclescancontractwithoutcuttingoffcirculation;andinnervestheycoursealonglikepowerlines,keepingthosenervesalive.Wegetmostofthesebloodvesselswhenwe'reactuallystillinthewomb,Andwhatthatmeansisthatasadults,bloodvesselsdon'tnormallygrow.Exceptinafewspecialcircumstances:
Inwomen,bloodvesselsgroweverymonthtobuildtheliningoftheuterus;duringpregnancy,theyformtheplacenta,whichconnectsmomandbaby.Andafterinjury,bloodvesselsactuallyhavetogrowunderthescabinordertohealawound.Andthisisactuallywhatitlookslike,hundredsofbloodvesselsallgrowingtowardthecenterofthewound.
Sothebodyhastheabilitytoregulatetheamountofbloodvesselsthatarepresentatanygiventime.Itdoesthisthroughanelaborateandelegantsystemofchecksandbalances,stimulatorsandinhibitorsofangiogenesis,suchthat,whenweneedabriefburstofbloodvessels,thebodycandothisbyreleasingstimulators,proteinscalledangiogenicfactorsthatactasnaturalfertilizerandstimulatenewbloodvesselstosprout.Andwhenthoseexcessvesselsarenolongerneeded,thebodyprunesthembacktobaselineusingnaturallyoccurringinhibitorsofangiogenesis.Nowthereareothersituationswherewestartbeneaththebaselineandweneedtogrowmorebloodvesselsjusttogetbacktonormallevels--forexample,afteraninjury--andabodycandothattoo,butonlytothatnormallevel,thatsetpoint.
Butwhatwenowknowisthatforanumberofdiseases,therearedefectsinthesystemwherethebodycan'tprunebackextrabloodvesselsorcan'tgrowenoughnewonesintherightplaceattherighttime.Andinthesesituations,angiogenesisisoutofbalance.Andwhenangiogenesisisoutofbalance,amyriadofdiseasesresult.Forexample,insufficientangiogenesis--notenoughbloodvessels--leadstowoundsthatdon'theal,heartattacks,legswithoutcirculation,deathfromstroke,nervedamage.Andontheotherend,excessiveangiogenesis--toomanybloodvessels--drivesdisease,andweseethisincancer,blindness,arthritis,obesity,Alzheimer'sdisease.Intotal,therearemorethan70majordiseasesaffectingmorethanabillionpeopleworldwide,thatalllookonthesurfacetobedifferentfromoneanother,butallactuallyshareabnormalangiogenesisastheircommondenominator.Andthisrealizationisallowingustoreconceptualizethewaythatweactuallyapproachthesediseasesbycontrollingangiogenesis.
NowI'mgoingtofocusoncancerbecauseangiogenesisisahallmarkofcancer,everytypeofcancer.Soherewego.Thisisatumor:
dark,gray,ominousmassgrowinginsideabrain.Andunderthemicroscope,youcanseehundredsofthesebrownstainingbloodvessels,capillariesthatarefeedingcancercells,bringingoxygenandnutrients.Butcancersdon'tstartoutlikethis.And,infact,cancersdon'tstartoutwithabloodsupply.Theystartoutassmall,microscopicnestsofcellsthatcanonlygrowtoonehalfacubicmillimeterinsize;that'sthetipofaballpointpen.Thentheycan'tgetanylargerbecausetheydon'thaveabloodsupply,sotheydon'thaveenoughoxygenornutrients.
Infact,we'reprobablyformingthesemicroscopiccancersallthetimeinourbody.Autopsystudiesfrompeoplewhodiedincaraccidentshaveshownthatabout40percentofwomenbetweentheagesof40and50actuallyhavemicroscopiccancersintheirbreasts,about50percentofmenintheir50sand60shavemicroscopicprostatecancers,andvirtually100percentofus,bythetimewereachour70s,willhavemicroscopiccancersgrowinginourthyroid.Yet,withoutabloodsupply,mostofthesecancerswillneverbecomedangerous.Dr.JudahFolkman,whowasmymentorandwhowasthepioneeroftheangiogenesisfield,oncecalledthis"cancerwithoutdisease."
Sothebody'sabilitytobalanceangiogenesis,whenit'sworki
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