Ukutya ebuchotsheni
Daniel Fisher, 01/10/05
Ngaba izinto ezityebileyo, ezineswekile esizinqwenelayo ziyakhobokisa? Nantsi into esixelela uphando lwenzululwazi yamva nje.
Kwilebhu e-Brookhaven National Laboratory e-Long Island, i-Gene-Jack Wang itofa abantu abatya kakhulu ngesisombululo seswekile ye-radioactive kwaye ibafake kumatshini we-positron-emissions tomography ukuze babone indlela ubuchopho babo obusabela ngayo ekutyeni. Ukuba izifundo zangaphambili zikaGqr Wang naziphi na izibonakaliso, Uya kubona ukuba i-striatum yesifundo sovavanyo, uhlobo lwehabhu yonxibelelwano ngaphakathi kwengqondo, ine-dopamine receptors ezimbalwa kune-striatum yomntu onemikhwa eqhelekileyo yokutya. UWang sele ebonisile ukuba ukubona nje kunye nevumba lokutya kunokubangela ukukhutshwa kwe-dopamine, i-neurotransmitter ehambelana nenkuthazo kunye nolonwabo. Ukwabonisiwe ukuba amakhoboka eziyobisi anokunqongophala okufanayo kwe-dopamine receptors.
I-PET scan yomsebenzisi we-methamphetamine ibonisa indawo enciphileyo ye-dopamine receptors efuna amachiza amaninzi ukunika ulonwabo.
http://www.forbes.com/forbes/2005/0110/063.html
Ukuskenwa kwe-PET kwesigulana esityebe kakhulu sibonisa ukunqongophala okufanayo kwee-dopamine receptors. Ngaba ukutya kungadlala indima efana neziyobisi?
Yongeza kwaye kuvela ithiyori: Abatya kakhulu batya ukutya okuninzi kunokulunga kubo ukuba bafumane ukukhaba okuziswa yi-dopamine-eso sizathu sinye sokuba i-cokeheads irhole i-cocaine. "Basebenzisa ukutya njengendlela yokubuyisela," utsho uWang, ugqirha oqeqeshwe nguJohns Hopkins ofunde ukuba likhoboka ngaphezu kweminyaka elishumi. Ithiyori kaWang ayinakuthetha nto ngaphandle kokuba iziyobisi ziphanga iisekethe zobuchopho ezifanayo eziye zavela kwizigidi zeminyaka ukukhuthaza abantu ukuba bafumane kwaye batye ukutya. Oko akuthethi ukuba ukutya sisiyobisi. Akukho mntu wakha warhoxa emva kokuhamba e-turkey ebandayo kwiiMacs ezinkulu, emva kwayo yonke loo nto.
Ukanti uphando lwakhe luneziphumo ezibi kwiinkampani zokutya njengoko zizama ukumangalelana ngendlela yecuba malunga nengxaki yokutyeba kwesizwe. Ukuba amagqwetha angabonisa ukuba ukutya kunempahla ekhobokisayo, banokuxoxa ukuba ukutya ngokugqithiseleyo akukhethi kodwa kukunyanzeliswa. Ukuba banokulandela ukunyanzeliswa kwizithako ezithile ezinje ngamafutha okanye isiraphu yombona ephezulu yefructose, banokuba nobungqina obulingana ne-nicotine-abavelisi bezinto abanokuthi baye benza ubuqhophololo ukuze badibanise abathengi babo ekutyeni.
UGqr. William Jacobs, ongumphandi wokutyeba ngokugqithiseleyo kwiYunivesithi yaseFlorida uthi: “Unokwenza izinto zibe likhoboka lazo. Kanye njengokuba i-cartel yaseColombia yenza i-crack cocaine.
Ukuza kuthi ga ngoku izazinzulu zisekude ekutyhileni i-fry yaseFransi etshayayo. Akukho mntu ufumene ubungqina obubambekayo bokuba abavelisi bathatha ithuba lesithako esiyimfihlakalo esogqitha ukhetho abazi, nangona abanye abantu becinga ukuba basondele ekusekeni kanye loo nto. UGqr. Neal Barnard weKomiti yeeGqirha kwi-Responsible Medicine, umbhali we-Breaking the Food Seduction St. Kwaye itshizi, uthi, iyaqhekeka ibe yi-casomorphins enokubakhobokisa kwi-digestive tract. “Kukho abantu abanqwenela isonka samasi,” utsho uBarnard, otya imifuno ekwakhutheleyo kwiphulo lokulwela amalungelo ezilwanyana. "Isebenza njengento ekhobokisayo."
Kodwa akukho bungqina bokuba i-casomorphins ingena egazini labantu abadala, ibaguqule babe yi-Brie-gobbling junkies. Abaphandi baye bafumanisa ubungqina bokuba ukutya okuthile kukhuthaza ukukhutshwa kwe-dopamine ngakumbi kwizilwanyana ezanyisayo kunabanye-okubaluleke kakhulu kwingxoxo esemthethweni yokuba oko kutya kukukhobokisa ngokungekho ngqiqweni kwaye kuyingozi-kodwa oko bakufumanisileyo kukuzama okanye kunzima ukuphinda-phinda ebantwini.
UAnn Kelley weYunivesithi yaseWisconsin, umzekelo, ubonise ukuba ukunika i-calorie-packed chocolate Qinisekisa, isongezelelo sokutya, kwiigundane kunciphisa ngokukhawuleza i-endorphins ebangela ukuzonwabisa, umphumo obonakalayo kwiigundane ezinikwe i-narcotics. Ukutya okuqhelekileyo akunayo impembelelo enjalo. "Intsingiselo yeyokuba ixesha elide lokutya ukutya okuthandwa kakhulu kunokuba nefuthe elinjengeziyobisi kwingqondo," utsho uKelley, omsebenzi wakhe uxhaswa ngemali ngokuyinxenye liziko elifumana imali kwaPepsiCo, iProcter & Gamble kunye nabanye abenzi bokutya.
Abaphandi baye babona iimpawu zokhetho olufanayo lobuchopho bokutya okuswiti nokunamafutha ebantwini. Sekunjalo, ubungqina abukacaci. U-Kelley unqume amanqanaba e-brain-endorphin ngokubulala kunye nokusabalalisa iigundane; I-PET scans nezinye iindlela ezingabulaliyo azichanekanga kangako.
Esinye sezifundo ezicatshulwe kakhulu, ngumphandi weYunivesithi yaseWashington uAdam Drewnowski, wafumanisa ukuba abafazi abanikwe iyeza elithintela i-opioid receptors badla ukutya okuncinci, okunamafutha aphezulu-kodwa kuphela ukuba bane-bulimic. Akanayo ingcaciso yokuba kutheni ichiza lingachaphazeli izidlo ze-12 izifundo zokulawula ubunzima obuqhelekileyo. I-opioid blocker "iyasebenza, siyayibona," utsho. "Kodwa kuphela kumntu ophazamisekileyo inkqubo."
Konke oku kungaqiniseki kuyaqondakala, xa kujongwa iindlela ezintsonkothileyo ezibangela ukutya nokutyeba ngokugqithiseleyo. Abavelisi bamayeza baye bazama ngelize ukufumana iyeza elimangalisayo eliya kwenza abantu banciphise umzimba; uninzi, njenge-fen-phen kunye ne-methamphetamines, zineziphumo ebezingalindelekanga ezibi kunengxaki abazama ukuyisombulula. I-Acomplia evela kwi-Sanofi-Aventis ivimbela i-cannabinoid receptors, i-brain receptors efanayo enika ababhemayo imbiza i-munchies, kodwa ibangela ukudakumba kwezinye izigulane (FORBES, "I-Pill Ultimate?" Dec. 13, 2004, p. 96).
Ukutyeba ngokugqithiseleyo kuqhutywa kwiintsapho-imizila yofuzo yodwa inokuqikelela ukuya kuthi ga kwi-40% yamathuba okuba utyebe kakhulu-kwaye nokutya kakhulu kubonakala kunxibelelene nezinye iingxaki ezinxulumene nosapho ezifana nokukhotyokiswa butywala kunye nokukhotyokiswa ziziyobisi. Zonke zibonakala zibandakanya ukuphazamiseka kwinkqubo yomvuzo wengqondo, ehambisa i-dopamine ebangela ulonwabo ekuphenduleni indlela yokusasaza iintlobo ezinjengokutya, ukusela amanzi okanye ukwabelana ngesondo. Iziyobisi zeCocaine, umzekelo, zinee-receptors ezimbalwa ze-dopamine ngenxa yokukhuthazwa rhoqo lichiza-ithintela abathuthi abaqhele ukubuyisela i-dopamine kwiiseli zobuchopho ukuze ziphinde zisetyenziswe-okanye ngenxa yokuba zazalwa ngolo hlobo.
Ukusuka Aroma ukuya Appetite
1. Isisu esingenanto sikhupha i-ghrelin, into evuselela umdla, kwi-hypo-thalamus, elawula i-metabolism yomzimba.
2. I-hypothalamus ikhupha i-dopamine kwi-nucleus accumbens kunye ne-striatum, ikhuthaza indawo yobuchopho ukuba ifumane ukutya.
3. Iphunga lokutya livuselela i-amygdala, kwakhona iziko leemvakalelo, kwaye kubangela ukukhululwa kwe-dopamine ngakumbi yi-nucleus accumbens.
4. Ukubona, ivumba kunye nencasa yokutya ivuselela ukukhululwa kwee-endorphins (opioids) kunye ne-dopamine nge-orbitofrontal cortex, ngakumbi ukuvuselela inxalenye yengqondo ukuba itye.
5. ILeptin ekhutshwe ziiseli zamafutha ekugqibeleni iyoyisa ighrelin kwaye inike umqondiso kwi-hypothalamus ukuba ivale ukuhamba kwe-dopamine. Ngenxa yoko, umdla uyaphela.
Abatya kakhulu banokunqongophala okufanayo kwe-dopamine receptors, kodwa abaphandi abazi ukuba ngaba ngumahluko ozuzwe njengelifa, omnye ophuhliswe ngokutya kakhulu okanye indibaniselwano yezi zimbini. Iingcali zenzululwazi nazo zikude nokutyhila unxibelelwano phakathi kweendawo ezizimeleyo zobuchopho ezilawula ukusetyenziswa kwamandla emihla ngemihla kunye nenkcitho, kunye nengqondo ephilileyo elawula ukuziphatha okufana nokuhamba ngaphesheya kwesitrato ukufumana i-bacon cheeseburger.
Ubunzima bomzimba bulawulwa kakhulu yi-hypothalamus, isakhiwo esisembindini wengqondo esilungisa i-metabolism ukuya kwinqanaba elingenakulinganiswa nekhalori-counter. Umphandi weYunivesithi yaseRockefeller uJeffrey Friedman ubale ukuba ukungalingani okumbalwa njenge-calories ye-1,700 ngonyaka kuya kukhokelela ekuzuzeni ubunzima okanye ekulahlekeni kwexesha. I-hypothalamus isabela kwi-ghrelin, ihomoni ekhutshwa sisisu esingenanto, ngokukhupha ii-neurotransmitters ezivuselela umdla kwezinye iindawo zobuchopho. Ivala ii-neurotransmitters ekuphenduleni i-leptin, ihomoni ekhutshwa ziiseli ezinamafutha.
Izazinzulu azikayazi ncam ukuba i-hypothalamus inxibelelana njani ne-cerebral cortex, indawo yokucinga, nangona i-dopamine kukholelwa ukuba idlala indima. Isiyobisi sokutya esingalunganga i-fenfluramine, umzekelo, yavuselela ukukhutshwa kwe-dopamine ngaphakathi kwe-hypothalamus kwaye yaba nefuthe elimangalisayo lokunciphisa umdla wokutya. I-hypothalamus nayo inonxibelelwano kwi-cortex nge-striatum kunye ne-nucleus accumbens, isakhiwo esifihla i-dopamine kunye ne-opioids ekuphenduleni ukutya (jonga umzobo).
Indima echanekileyo ye-nucleus accumbens iyimfihlakalo. Isebenza ngolwazi oluvela emlonyeni nasempumlweni-wow, loo pizza inuka kamnandi!-kwaye ikhupha i-dopamine kunye ne-opioids ekuphenduleni. Abaphandi baye babona i-bias yokutya okunamafutha ngokuchasene ne-carbohydrates, into abangenakuyichaza. Ukuvuselela i-nucleus accumbens kwiigundane kwaye ziyazikhukhumeza kwizinto; lawula i-opioid blocker kwaye bayayeka. Iimpuku ezifuywe ngaphandle kwe-dopamine receptors kwi-nucleus accumbens ngokukhawuleza zibulawa yindlala.
U-Ann Kelley ufumene umaleko onamandla ngakumbi wolawulo kwi-amygdala, iziko leemvakalelo elikwanonxibelelwano lwemithambo-luvo olutyebileyo empumlweni. Xa engathathi hlangothi i-amygdala kwiigundane kunye neyeza elimisa umsebenzi walo, ayisaqhubeki nokuba i-nucleus accumbens yazo ivuselelwe. Intsingiselo, uthi, kukuba impendulo yeemvakalelo ekutyeni kunye namavumba alo-khumbula i-popcorn owawunayo ngomhla wakho wokuqala?-inokuba ibaluleke ngakumbi kunenkqubo yokulawula ubunzima be-hypothalamus. Inye intsingiselo: Amaphulo eNtengiso enza imifanekiso yekhaya kunye neziko anokuthi avuselele i-amygdala.
Inyaniso kukuba, ingqondo yomntu inentaphane yeendlela zokuvuselela umdla wokutya yaye zimbalwa kuphela zokuyicima. Oko kusengqiqweni ngokwembono yendaleko kuba kude kube kutshanje uluntu belukwimeko yokunqongophala kokutya okungapheliyo. “Cinga ngoku: Ubuchopho bakho buhamba kwezi zitolo ezinkulu kwaye uthi, 'Andingomzingeli omkhulu? Ndinokubamba iisalmon zikakumkani okanye inyama yenkomo yeKobe ngaphandle kwamathuba okuhlaselwa lihlosi elinamazinyo amhlophe,” utsho uMark Gold, unjingalwazi obalaseleyo wenzululwazi yemithambo-luvo kwiMcKnight Brain Institute kwiYunivesithi yaseFlorida.
Umbuzo oxabisa izigidi ngezigidi zeedola ngowokuba ingaba izithako ezithile zokutya ezilawulwa ngokulula zinokubangela enye yezo ndlela ithi “yitya,” nokuba amanye amalungu engqondo athi “kwanele.” Igqwetha uChristopher Cole kwiofisi yaseWashington kaPaul, uHastings Janofsky & Walker ucebisa iinkampani zokutya malunga nezicwangciso zokukhusela kufuneka ukuba izimangalo zokutya ziqale. Ukuza kuthi ga ngoku akakaboni nto kuphando anokuzikhathaza ngayo. Kodwa ubeke iliso elibukhali kwiijenali zokutyeba: “Emva kokuba ubonakalise [ukutyeba] njengesigulo kwaye uphikisa ngelithi iinkampani zibongoza abantu ukuba basibambe eso sigulo, unokwakha ityala.”
;