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Postoji li naučni dokaz da pušenje kvari kožu lica?

Postoji li naučni dokaz da pušenje kvari kožu lica?


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Vidio sam da pušači cigareta (više od 3 cigarete dnevno) često imaju malo pokvarenu kožu lica.

Postoji li znanstveni dokaz da dim cigarete (ili nikotin u njemu) šteti koži lica?

Ili je to samo zbog interakcije kože i dima uzrokovane dimom koji osoba izdiše na usta?


Ova stranica je prilično puna primjera i referenci.

Ukratko, mnogi dokazi su empirijski – gledate pušače i kvalitet njihove kože i uporedite ih s nepušačima i razlike su statistički značajne i reproducibilne. Čini se kao da je ovo staro djelo, koje datira iz 1970-ih.

Dakle, u mnogim slučajevima to su samo uočene korelacije. Ali se medicinski ljudi prilično slažu s njima. S obzirom na činjenicu da još uvijek ne znamo tačno šta uzrokuje rak, mislim da ovo nije neobičan nivo objašnjenja za medicinska stanja.

Kao što vidite, neke teorije bi uključivale direktne efekte dima i neke indirektne efekte.

Nije sigurno kako tačno pušenje uzrokuje rano starenje kože lica. Teorije uključuju:

  • Toplota iz cigarete direktno gori kožu
  • Promjene u elastičnim vlaknima kože
  • Sužavanje krvnih žila (vazokonstrikcija), što smanjuje dotok krvi u kožu i može uzrokovati promjene u elastičnim vlaknima kože i gubitak kolagena
  • Smanjenje nivoa vitamina A i vlažnosti kože

Kako pušenje uzrokuje rano starenje i preuranjene bore

Sharon Basaraba je nagrađivana novinarka i viša savjetnica za naučne komunikacije za Alberta Health Services u Alberti, Kanada.

Armeen Poor, MD, je certificirani pulmolog i intenzivista. Specijalizirao se za plućno zdravlje, intenzivnu njegu i medicinu spavanja.

Gilbert Laurie / Getty Images

Pušenje negativno utječe na gotovo svaki organ vašeg tijela, a to uključuje i najveći organ: vašu kožu. Dim cigarete sadrži toksine koji utiču na kvalitet vaše kože, što dovodi do bora, preranog starenja i potencijalno čak i stanja kože.

Važno je postati svjestan efekata pušenja na kožu, a može čak i da vas motiviše da prestanete da pušite.


Uobičajene zablude o nauci I: “Naučni dokaz”

Zabluda o prirodi i praksi nauke obiluju i ponekad ih drže i sami inače ugledni naučnici. Neke od njih (zablude, a ne naučnike) sam raspršio u ranijim objavama (na primjer, da je ljepota u oku posmatrača, ljepota je samo do kože, a o knjizi ne možete suditi po koricama).

Nažalost, postoje mnoge druge zablude o nauci. Jedna od najčešćih zabluda odnosi se na takozvane “naučne dokaze”. Suprotno popularnom mišljenju, ne postoji znanstveni dokaz.

Dokazi postoje samo u matematici i logici, ne i u nauci. I matematika i logika su zatvoreni, samostalni sistemi propozicija, dok je nauka empirijska i bavi se prirodom kakva postoji. Primarni kriterijum i standard evaluacije naučne teorije je dokaz, a ne dokaz. Sve ostale jednake (kao što su unutrašnja logička konzistentnost i štedljivost), naučnici preferiraju teorije za koje ima više i boljih dokaza od teorija za koje ima manje i lošijih dokaza. Dokazi nisu valuta nauke.

Dokazi imaju dvije karakteristike koje ne postoje u nauci: jesu final, i jesu binarni. Jednom kada se teorema dokaže, ona će zauvijek biti istinita i neće biti ničega u budućnosti što će ugroziti njen status dokazane teoreme (osim ako se ne otkrije nedostatak u dokazu). Osim otkrivanja greške, dokazana teorema će zauvijek i uvijek biti dokazana teorema.

Nasuprot tome, sva naučna saznanja jeste probno i provizorno, i ništa nije konačno. Ne postoji nešto kao konačno dokazano znanje u nauci. Trenutno prihvaćena teorija fenomena jednostavno je najbolje objašnjenje za to među svim raspoloživim alternativama. Njen status prihvaćene teorije ovisi o tome koje su druge teorije dostupne i može se iznenada promijeniti sutra ako se pojavi bolja teorija ili novi dokazi koji bi mogli osporiti prihvaćenu teoriju. Nijedno znanje ili teorija (koja utjelovljuje naučno znanje) nije konačna. To je, inače, razlog zašto je nauka tako zabavna.

Nadalje, dokazi, kao i trudnoća, su binarni, a matematička tvrdnja je ili dokazana (u tom slučaju postaje teorema) ili ne (u tom slučaju ostaje pretpostavka dok se ne dokaže). Ne postoji ništa između. Teorema ne može biti na neki način dokazana ili gotovo dokazana. Ovo je isto kao i nedokazano.

Nasuprot tome, ne postoji takva binarna evaluacija naučnih teorija. Naučne teorije nisu ni apsolutno lažne ni apsolutno istinite. Oni su uvek negde između. Neke teorije su bolje, vjerodostojnije i prihvaćenije od drugih. Za neke teorije uvijek postoji više, vjerodostojnijih i boljih dokaza od drugih. To je pitanje više ili manje, a ne ili/ili. Na primjer, eksperimentalni dokazi su bolji i vjerodostojniji od korelacijskih dokaza, ali čak ni prvi ne mogu dokazati teoriju, već samo pružaju vrlo jake dokaze za teoriju i protiv njenih alternativa.

Saznanje da ne postoji takva stvar kao što je naučni dokaz trebalo bi da vam pruži veoma lak način da razlikujete prave naučnike od hakera i navijača. Pravi naučnici nikada ne koriste reči „naučni dokazi“, jer znaju da tako nešto ne postoji. Svako ko koristi riječi “dokaz”, “dokaži” i “dokazano” u svojoj raspravi o nauci nije pravi naučnik.

Kreacionisti i drugi kritičari evolucije su potpuno u pravu kada ističu da je evolucija “samo teorija” i da nije “dokazana”. Ono što zanemaruju da spomenu je to sve u nauci je samo teorija i nikada nije dokazana. Za razliku od teoreme o prostim brojevima, koja će apsolutno i zauvijek biti istinita, još uvijek je moguće, iako vrlo, vrlo, vrlo, vrlo, vrlo, vrlo malo vjerovatno da će se teorija evolucije prirodnom i seksualnom selekcijom jednog dana pokazati lažnom. Ali opet, moguće je, iako vrlo, vrlo, vrlo, vrlo, vrlo malo vjerovatno, da će mi majmuni sutra izletjeti iz guzice. Po mom sudu, oba događaja su približno podjednako verovatna.


Kako su države počele legalizirati marihuanu, otvorenije se raspravljalo o njenoj upotrebi. Dok su efekti drugih najčešće korištenih droga, kao što je alkohol, opširno proučavani, efekti marihuane – posebno na bebe u razvoju tokom trudnoće – su mnogo manje proučavani i manje publicirani. Ova relativna šutnja naučne zajednice utjecala je na mišljenje javnosti o sigurnosti marihuane: 70 posto žena u SAD-u misli da postoji "mali ili nikakav rizik od štete" za bebu od upotrebe marihuane tokom trudnoće. Buduće majke mogu koristiti marihuanu umjesto lijekova na recept tokom trudnoće kako bi ublažile bol jer smatraju da su „prirodni“ ili su kućni lijekovi sigurnija opcija od lijekova na recept. Međutim, samo zato što je nešto "prirodno" ne znači da je sigurnije ili bolja alternativa dobro proučenim lijekovima na recept. Čini se da je to slučaj sa marihuanom. S obzirom da je marihuana najčešće korištena zabranjena droga tokom trudnoće, važno je razumjeti njene rizike i utjecaje na fetus u razvoju.

Tri velike longitudinalne studije pratile su kako je upotreba kanabisa od strane majki utjecala na razvoj njihovog djeteta, i imale su iznenađujuće konzistentne rezultate. Ottawa prenatalna prospektivna studija ispitala je 700 trudnica koje su koristile marihuanu 1978. godine i pratila je oko 200 te djece u odrasloj dobi. Studija o zdravlju majki i razvoju djeteta sa sjedištem u SAD proučavala je 580 djece korisnika marihuane od trudnoće do 14 godina. Studija generacije R prati skoro 8.000 djece u Holandiji.

Djeca korisnika marihuane bila su impulzivnija i hiperaktivnija, te su pokazivala probleme u ponašanju, niži IQ i probleme s pamćenjem u poređenju s djecom ne-korisnika. Ovi problemi sa mentalnim zdravljem nastavili su se tokom tinejdžerskih godina, kada je bila znatno veća vjerovatnoća da će imati problema sa pažnjom i depresiju. Djeca izložena marihuani također su imala skoro dvostruko veću vjerovatnoću da pokažu delikventno ponašanje, kao što je upotreba droga, do 14. godine i više nego dvostruko češće nego odrasli. Veoma konzistentni rezultati između istraživanja na miševima i ljudima (sažeti u infografici iz Naučnik u nastavku) naglašava sve veće razumijevanje uticaja upotrebe marihuane na razvoj.

Važno je napomenuti da neki ishodi ponašanja možda nisu u potpunosti povezani s izloženošću fetusa marihuani. Djeca korisnika marihuane su možda odrasla u drugačijem društvenom okruženju s opuštenijim pogledima na droge, što je doprinijelo njihovoj povećanoj upotrebi droga.

Kako se marihuana nastavlja legalizirati, trebali bismo očekivati ​​da ćemo vidjeti više studija o njenim zdravstvenim učincima i sigurnosti.


Stručna medicinska tijela, uključujući Američku akademiju za pedijatriju (AAP), pozivaju roditelje da vakcinišu svoju djecu protiv 16 bolesti. CDC raspored vakcinacija u djetinjstvu, koji se oslanja na preporuke Savjetodavnog odbora za praksu imunizacije i koji je odobren od strane AAP-a, sastavljen je na osnovu podataka koji detaljno navode kada će imunološki sistem tijela dati najbolji odgovor na vakcinu i, drugo, uravnotežen protiv potrebe za zaštitom djece u najranijoj dobi. Nema naučnih podataka koji bi ukazivali na medicinsku korist od raspoređivanja vakcina na duži period od zvaničnih preporuka.

Vakcine se također redovno procjenjuju u pogledu sigurnosti. Prije nego što se dodaju preporučenom režimu, moraju se podvrgnuti testiranju kako bi bili sigurni da neće ometati jedni druge. Više studija je takođe procenilo kumulativne efekte vakcina.

Ipak, pedijatri se suočavaju sa stalnim pritiskom nekih zabrinutih roditelja koji možda žele da rašire preporučene vakcinacije ili da odlože određene vakcinacije, odluke koje mogu produžiti period osetljivosti na bolest. Na primjer, nacionalno reprezentativna studija objavljena u aprilu 2015 Pedijatrija otkrili su da je u prosjeku mjesec dana 93 posto anketiranih ljekara primilo barem jedan zahtjev od roditelja da rašire injekcije. I to se dešavalo prilično često: preko petine od 534 ispitana ljekara je izjavilo da je 10 posto roditelja uputilo takve zahtjeve. Želje roditelja su se tada često poštovale i većina ispitanih kliničara je na kraju pristala na to, barem u nekim slučajevima.

Ipak, strahovi da djetetov organizam neće moći podnijeti moćne vakcine su pogrešni. Imuni sistem djece reagira na nekoliko stotina stranih supstanci koje svakodnevno izazivaju imunološki odgovor. Nasuprot tome, kompletan raspored preporučenih vakcinacija u djetinjstvu uključuje manje od 200 antigena.


IV. Ostala laboratorijska ispitivanja

Rak kože kod glodara

Jedna od karika u ukupnom dokazu o uzročno-posledičnoj vezi pušenja cigareta i raka pluća je demonstracija da kondenzati duhanskog dima (koji se obično nazivaju "katrani") imaju biološko svojstvo izazivanja karcinoma kod određenih laboratorijskih životinja, posebno kod miševa. Proizvodnja raka kože kod miševa, nakon ponovljenih, dugotrajnih primjena duhanskog katrana, sada je prijavljena u najmanje šest različitih laboratorija 20, 21, 22, 23, 24, 76 . Neosporno je da neki istraživači nisu dobili pozitivne rezultate, možda zato što su doza i drugi eksperimentalni uslovi bili različiti, ili zato što su složeni duhanski katrani vjerovatno uvelike varirali u svom sastavu. Negativni rezultati Passeya et al. 18 su citirali Hueper 38 i drugi, ali noviji eksperiment Passeya 24 sa miševima švicarskog soja je doveo do pojave najmanje dva karcinoma nakon ponovljenih primjena kondenzata duhanskog dima.

Little 29 je naznačio da je „… ekstrapolacija rezultata dobijenih slikanjem ili ubrizgavanjem u kožu miševa na ljudska pluća krajnje upitna“. Direktna ekstrapolacija s jedne vrste na drugu, naravno, nije opravdana. Ipak, rezultati na životinjama u potpunosti su u skladu s epidemiološkim nalazima kod čovjeka. Prikladan je citat iz Kotina 49: „Kemijska demonstracija kancerogenih agenasa u okolini i njihova uspješna upotreba za proizvodnju tumora kod pokusnih životinja ne dokazuje ili čak posebno snažno ukazuje na sličan odnos kod čovjeka. Međutim, kada postoji uočljiv paralelizam između epidemioloških podataka i laboratorijskih nalaza, veći značaj ima i jedno i drugo. Medicinska historija je prepuna primjera u kojima je dokazano da laboratorijski nalazi imaju svoj pandan u ljudskom iskustvu. Izuzetaka je bilo vrlo malo.”

Greene 37 , dok odbacuje značaj indukcije karcinoma kože kod švicarskih miševa zbog konstitucijske “visoke diferencijalne osjetljivosti” soja, vjeruje da je neuspjeh induciranja neoplazmi u embrionalnim transplantacijama izloženim duhanskom katranu važniji dokaz. Greeneova zanimljiva tehnika daje pozitivne rezultate kada se koriste čiste hemikalije kao što je benzo[α]piren, a ova hemikalija je izvučena iz nekih uzoraka kondenzata duhanskog dima. Nismo upoznati sa izvještajima o novotvorinama koje nastaju u embrionalnom tkivu koje je izloženo in vitro na katran ugljena, još jednu sirovu mješavinu koja sadrži karcinogene.

Visoka učestalost indukcije karcinoma koju je prijavio Wynder et al. 76 nisu postigli drugi istraživači, koji su izvijestili da je ne više od 20 posto životinja, a obično znatno manje, razvilo karcinom kože. Gellhorn 22 i Bock i Moore 20 pokazali su prisutnost kokarcinogenih materijala u kondenzatu duhanskog dima. Podacima o mišu se sada dodaju podaci o indukciji raka kože kod nekih zečeva obojenih kondenzatom duhanskog dima 77 ovaj kondenzat, kada se kombinuje sa ubijenom suspenzijom bacila tuberkuloze, i unese u bronh, stvara karcinom bronha u jednom štakoru 78 .

Budući da su maligne neoplazme dobivene u nekoliko sojeva miševa, a nekoliko neoplazmi je proizvedeno kod zečeva i pacova, pitanje ograničenja soja ili vrste na reakciju je teže održavati. Naravno, činjenica je da mnoga sredstva za koja se pokazalo da su kancerogena za kožu miševa nisu dokazana kao kancerogena za čovjeka. U većini slučajeva jednostavno nema iskustva s takvim agensima kod čovjeka, tako da nedostatak dokaza zaista predstavlja nedostatak podataka, za i protiv.

Problem doze

Little 29 je dalje doveo u pitanje primjenjivost podataka o životinjama na čovjeka, na sljedeći način: “Duvanski dim ili kondenzat dima nisu uspjeli proizvesti rak čak ni na koži osjetljivih sojeva miševa kada se primjenjuju u količini i stopi izlaganja koja bi simulirala uvjete pušenja kod ljudi.”

Razlike u vrstama, tkivima i stanjima između indukcije neoplazmi na koži miševa i u bronhima čovjeka, onemogućuju fina poređenja odnosa doze i vremena.

Bronhogeni karcinom kod životinja

Adenomatozni tumor pluća kod miševa, pacova i zamoraca ne može se porediti sa bronhogenim karcinomom kod ljudi 71 . Do prije nekoliko godina eksperimentalna indukcija epidermoidnog karcinoma bila je postignuta samo kod nekoliko miševa prolaskom niza impregniranih kancerogenim ugljovodonicima kroz pluća. Epidermoidni karcinom pluća konzistentno je nastajao kod pacova berilijumom 79 , kancerogenim ugljovodonicima unešenim kao fiksirane pelete u bronhije pacova 80 i inhalacijom radioaktivnih čestica 81 .

Little 29 je primijetio da “... produženo izlaganje pluća glodara ogromnim dozama dima cigareta nije uspjelo proizvesti bronhogeni rak.” To je i dalje istina u vrijeme ovog izvještaja, iako se može postaviti pitanje prima li bilo koja životinja toliku dozu dima cigarete kroz indirektno izlaganje kao ljudsko biće dobrovoljnim dubokim udisanjem. Stoga kvar može biti tehnički, što se može riješiti daljim eksperimentiranjem. Rani rezultati Leuchtenbergera et al. 19 sugerisao da se to može postići.

Karcinogeni u duvanskom dimu

Izolacija i identifikacija specifičnih hemijskih sastojaka u duvanskom dimu, koji su kancerogeni za plućno tkivo čoveka, važno je područje istraživanja.

Već neko vrijeme je jasno da će sagorijevanje ili piroliza većine organskih materijala, uključujući duhan, formirati više aromatične policiklike utvrđene kancerogene aktivnosti 28 . Određeni broj viših aromatičnih policiklika je identificiran i izoliran (23, 25, 26, 27). Ovi materijali uključuju benzo[e]piren, benzo[a]piren, dibenz[a,h]antracen, krizen i, nedavno, novoustanovljeni kancerogen, 3,4-benz-fluoranten. Da li su ova jedinjenja podjednako uključena u humanu plućnu karcinogenezu je, naravno, pretpostavka.

Little 29 implicira da se mora pronaći specifičan sastojak koji bi objasnio biološku aktivnost duvanskog dima. Ovo nije neophodno. Situacija je slična utvrđivanju kancerogene aktivnosti katrana, što je prihvaćeno prije izolacije benzo[a]pyrene od strane Kennawaya i njegovih saradnika. U ovom slučaju, također, benzo[a]piren najvjerovatnije nije jedini kancerogen u složenoj mješavini zvanoj katran, a postoje jake indicije da neke nekancerogene komponente u katranu mogu imati kokarcinogene efekte.


Boots krema protiv bora zapravo djeluje, kažu istraživači

Kada je dokumentarni film objavio da Boots krema protiv starenja zaista djeluje, zalihe seruma su nestale brže od mrštenja, a cjelogodišnje zalihe losiona nestale su s polica u roku od dvije sedmice. Ali ludnica oko asortimana "No7 Protect and Perfect" možda ipak nije bila tako napola pečena.

Rezultati onoga što se smatra prvim pouzdanim kliničkim ispitivanjem bilo koje kreme protiv bora dostupne na glavnoj ulici sugeriraju da zaista pomaže u smanjenju bora.

U onome što bi moglo izazvati drugi talas histerije oko proizvoda, naučnici sa Univerziteta u Mančesteru zaključili su da je oko petine ljudi koji su koristili kremu šest meseci primetili neka poboljšanja na svojoj koži.

Naučnici su pozdravili ispitivanje, koje je upoređivalo Boots "No.7 Protect and Perfect intense beauty serum" sa hidratantnom kremom, koji su rekli da je "podigao ljestvicu" na vrste testova koje kozmetičke kompanije treba da urade prije nego što podnesu tvrdnje o svojim proizvodima.

Nezavisna istraga BBC-jevog programa Horizon prošle godine dovela je do testiranja proizvoda iz iste palete krema nakon što je utvrđeno da je jedina testirana koja ima ikakav povoljan učinak.

"Vrlo malo kozmetičkih proizvoda protiv starenja bez recepta je podvrgnuto rigoroznom, naučnom ispitivanju kako bi se dokazala njihova efikasnost", rekao je Chris Griffiths, dermatolog i vođa nove studije.

Dokazano je da lijekovi koji se izdaju na recept poznati kao retinoidi popravljaju kožu koja je ostarjela izlaganjem suncu, ali nema dovoljno dokaza da mnoštvo kozmetičkih proizvoda protiv starenja ima sličan učinak, dodao je Griffiths.

U studiji je 49 žena i 11 muškaraca u dobi između 45 i 80 godina koristilo ili proizvod protiv bora ili placebo hidratantnu kremu šest mjeseci. Na kraju perioda, 43% onih koji su koristili kremu protiv bora uočilo je poboljšanje stanja kože, u poređenju sa 22% onih koji su koristili placebo kremu.

Testovi na koži volontera pokazali su da oni koji su koristili kremu protiv starenja proizvode protein nazvan fibrilin-1, koji kožu čini elastičnijom. Istraživanje je objavljeno u British Journal of Dermatology.

Richard Weller, dermatolog sa Univerziteta u Edinburgu, rekao je da je ovo istraživanje prvo ispravno ispitivanje kozmetičkog proizvoda bez recepta. Rekao je da je u izvještaju nejasno koliko krema smanjuje bore kod ljudi i da je malo vjerovatno da će biti tako efikasna kao retinoidi, koji se mogu propisati samo preko ljekara opšte prakse.

Ali ispitivanje pokazuje da bi i drugi proizvodi protiv starenja mogli biti efikasni u smanjenju bora.

"Sastojci u Protect i Perfectu dostupni su i drugim kozmetičkim kompanijama, a mnogi od njih se koriste i u drugim markama kozmetike. Ne bi me iznenadilo da i druga kozmetika pokazuje slične efekte, ali na konkurentskim kozmetičkim kompanijama je da to pokažu, “, rekao je Weller. „Ono što je najvažnije, mislim da će ovo podići ljestvicu za ono što trebamo očekivati ​​od kozmetičkih kompanija u pokazivanju da njihovi proizvodi djeluju.“

Nina Goad, glasnogovornica Britanskog udruženja dermatologa, rekla je: "Približno jedna od pet osoba koje koriste kremu će dobiti nešto dodatno za svoj novac u odnosu na obične hidratantne kreme. To je zanimljiv korak naprijed u istraživanju, iako su dugoročne prednosti nepoznato. Glavni uzroci starenja kože koji se mogu spriječiti su izlaganje suncu i pušenje, pa ako ste zabrinuti zbog bora, razumno je ograničiti ove faktore."


Da li je homoseksualnost izbor?

Postavite ovo pitanje i vjerovatno ćete dobiti jedan od dva odgovora:

Da. Ljudi biraju da budu gej. Oni čine nemoralan izbor, koji vlada treba da obeshrabri.

Ne. Seksualna sklonost je biološki određena. Vlada treba da zaštiti homoseksualce od diskriminacije jer je homoseksualnost nepromjenjiv aspekt njihovog identiteta.

Ova dva odgovora imaju nešto zajedničko: sa oba, nauka pogodno podržava moralnu odluku.

&ldquoBiti gej je loše. Kako je divno što niko ne mora biti gej!&rdquo

&ldquoHomoseksualno ponašanje treba dozvoliti. Nije li&rsquot fantastično da, nevjerovatnom slučajnošću, nema načina da se to zaustavi?&rdquo

Šta ako nijedan odgovor nije tačan?

Možda se seksualne preferencije mogu promijeniti &ndash i ljudi imaju pravo na gej seks i homoseksualne odnose ako to žele. (Četvrta opcija, da homoseksualci nemaju izbora osim da budu gej, ali da ih zbog toga ionako treba kazniti, moralno je nezamisliva.)

Šta nam nauka govori o seksualnim preferencijama?

Znamo, iz mnogih studija blizanaca i usvajanja, da seksualna sklonost ima genetsku komponentu.

Veća je vjerovatnoća da će gej muškarac nego strejt muškarac imati (biološkog) gej brata, verovatnije je da će lezbejke nego strejt žene imati gej sestre.

Godine 1993., studija objavljena u časopisu Science pokazala je da porodice sa dva homoseksualna brata vrlo vjerovatno imaju određene genetske markere na području X hromozoma poznatom kao Xq28. To je dovelo do medijskih naslova o mogućnosti postojanja &ldquogay gena&rdquo i diskusija o etici pobačaja &ldquogay&rdquo fetusa.

Pojavili su se i naslovi o &ldquoalkoholnom genu&rdquo, zbog kojeg ljudi postaju alkoholičari, i o &ldquoratnom genu&rdquo, koji ljude čini neobično agresivnim.

Međutim, geni mogu u potpunosti kontrolirati ponašanje. Geni regulišu proizvodnju aminokiselina, koje se kombinuju i formiraju proteine. Postojanje ili odsustvo proteina može uticati na stvari poput tolerancije alkohola ili raspoloženja.

Utjecati na nešto nije isto što i imati potpunu kontrolu nad tim.

Okruženje, kao i genetika, igra važnu ulogu u tome kako se naše ponašanje razvija.

Alkoholizam se javlja u porodicama ne samo zato što postoji genetska komponenta alkoholizma, već i zato što djeca uče kako se nositi sa stresom gledajući kako se njihovi roditelji i njihova starija braća i sestre ponašaju u stresnim situacijama.

Ako dolazite iz kulture u kojoj je konzumacija alkohola zabranjena, teško ćete postati alkoholičar, bez obzira na to kako vaše tijelo metabolizira alkohol.

Postoje faktori osim &ldquoratničkog gena&rdquo koji doprinose agresiji. Djeca uče da se ponašaju agresivno kada budu svjedoci da je agresija nagrađena.

Ako ste odrasli u porodici ili kao dio kulture u kojoj agresija nije bila dobro prihvaćena, manje je vjerovatno da ćete biti agresivni. Od ranog detinjstva naučili biste kako da kontrolišete svoje agresivne sklonosti.

Vaše okruženje utiče na vaše seksualne i romantične odnose.

Kroz istoriju na brakove su uticali porodični odnosi i ekonomske potrebe.

Ljudi se pridržavaju kulturnih ograničenja monogamije uprkos tome što ih privlače ljudi koji nisu njihovi supružnici.

Vaša kultura utiče na vaše poglede na homoseksualnost.

U nekim društvima homoseksualnost je prihvaćena, u drugim se na nju ne gledaju, ali se tolerišu, u trećima je to teško krivično djelo, za koje je moguće da se kažnjava smrću.

Homoseksualno ponašanje muškaraca se očekivalo u staroj Atini. Danas ritualna muška homoseksualnost igra važnu ulogu u nekim kulturama Nove Gvineje.

Vaše vaspitanje može uticati na ono što smatrate poželjnim, a šta odbojnim. Većina Amerikanaca bi vjerovatno imala mučninu kada bi saznala da, kada su mislili da su jeli govedinu, u stvari jedu pseće meso, iako u psećem mesu nema ničeg nezdravog.

Ono što ste naučili o homoseksualnosti dok ste odrastali će uticati na to da li smatrate da je bavljenje homoseksualnim činovima poželjno ili odvratno.

Neki ljudi bi mogli tvrditi da ako ste &ldquogenetski gej&rdquo, ali vas pomisao na homoseksualnost muči, onda jednostavno niste&rsquot prihvatili činjenicu da ste zaista gej. Taj argument se zasniva na pretpostavci da je seksualna preferencija čisto biološka, ​​stoga mu nema mjesta u raspravi o mogućim uzrocima homoseksualnosti.

Struktura mozga može uticati na seksualne preferencije.

1991. godine, studija objavljena u časopisu Science izgleda da je pokazala da se hipotalamus, koji kontroliše oslobađanje polnih hormona iz hipofize, kod homoseksualaca razlikuje od hipotalamusa kod strejt muškaraca. Utvrđeno je da je treće intersticijalno jezgro prednjeg hipotalamusa (INAH3) više nego dvostruko veće kod heteroseksualnih muškaraca nego kod homoseksualnih muškaraca.

Ova studija je kritikovana jer je koristila moždano tkivo dobijeno na obdukcijama, a vjerovalo se da su svi homoseksualni subjekti u studiji umrli od AIDS-a.

Kasnija studija, koja je obavljena 2001. godine, pokazala je da HIV status nema značajan uticaj na INAH3. Ova studija, koja je također koristila moždano tkivo s obdukcija, nije otkrila nikakvu značajnu razliku između veličine INAH3 kod homoseksualaca i strejt muškaraca. Međutim, pokazalo je da su kod gej muškaraca neuroni u INAH3 zbijeniji zajedno nego kod strejt muškaraca.

PET i MRI studije provedene 2008. godine pokazale su da su dvije polovice mozga simetričnije kod homoseksualnih muškaraca i heteroseksualnih žena nego kod heteroseksualnih muškaraca i homoseksualnih žena. Ove studije su takođe otkrile da veze u amigdali gej muškaraca liče na veze strejt žena kod gej žena, veze u amigdali liče na veze strejt muškaraca. Amigdala ima mnogo receptora za polne hormone i povezana je s obradom emocija.

Neka istraživanja su pokazala da corpus callosum – što je glavna veza između dvije polovice mozga – ima drugačiju strukturu kod homoseksualaca nego kod strejt muškaraca. Međutim, druge studije nisu pronašle nikakvu razliku.

Prema brojnim različitim studijama, gej žene i gej muškarci češće će biti ljevoruki ili ambidekstralni od strejt žena i strejt muškaraca. Neki istraživači su sugerirali da se ova razlika u rukovanju &ndash preferencija jedne ruke nad drugom može primijetiti kod fetusa - povezana je s razlikama u corpus callosum.

Studija iz 1992. je pokazala da je prednja komisura, manja veza između mozga i dvije hemisfere, veća kod homoseksualnih muškaraca nego kod strejt muškaraca. Međutim, prema studiji koja je obavljena deset godina kasnije, na veličinu prednje komisure ne utiče seksualna orijentacija.

Iz proučavanja pacova znamo da izlaganje polnim hormonima u maternici tokom kritičnog perioda u razvoju mozga utiče na buduću seksualnu orijentaciju. Manipulišući nivoima hormona tokom ovog perioda, naučnici mogu naterati pacove da se kasnije uključe u homoseksualno ponašanje.

Dakle, vaš mozak je utjecao na vaše seksualne preferencije čak i prije nego što ste rođeni.

Ovo može objasniti zašto mnogi homoseksualci smatraju da su oduvijek bili gej.

Međutim, razvoj mozga ne prestaje rođenjem.

Veliki dio razvoja mozga odvija se tokom djetinjstva, kada učite mnoge nove stvari &ndash uključujući kako vaša porodica i odrasli oko vas vjeruju da biste trebali osjećati stvari i ono što smatraju prihvatljivim ponašanjem.

Obrazovanje koje ste dobili kao dijete snažno utječe na to kako će se vaš mozak razvijati kako rastete. Na primjer, djeca kojima se daje muzička obuka doživljavaju promjene u područjima mozga koja su povezana sa kontrolom sluha i motora.

Uz prava iskustva, vaš mozak se može promijeniti čak i nakon što ste postali odrasli.

I londonski taksisti i profesionalni tjuneri klavira pokazuju povećanje sive tvari u područjima mozga koja su povezana s vještinama potrebnim za njihove profesije. Veličina povećanja sive tvari korelira s brojem godina iskustva.

U jednom eksperimentu, stariji ispitanici su pokazali povećanje sive tvari u određenim dijelovima mozga nakon što su ih naučili žonglirati.

Uz odgovarajuću rehabilitaciju, ljudi koji su pretrpjeli oštećenje mozga od moždanog udara mogu razviti nove neuronske veze i povratiti neke od svojih starih vještina.

Važno je naglasiti da regije mozga za koje se pokazalo da se mijenjaju zbog treninga i iskustva nisu dijelovi mozga koji su povezani sa seksualnim preferencijama.

Međutim, žene doživljavaju promjene u strukturi hipotalamusa &ndash za koje se smatra da su povezane sa seksualnom orijentacijom - tokom menstrualnog ciklusa.

Do sada, pokušaji da se homoseksualnost &ldquoleči&rdquo operacijama na mozgu &ndash homoseksualcima je nekada davana lobotomija - nikada nisu uspjeli.

(Nisu bili efikasni pokušaji da se eliminiše homoseksualnost putem hormonske terapije. Iako promene nivoa hormona u materici tokom veoma određenog vremena mogu uticati na buduće seksualne preferencije, nivoi hormona nemaju uticaja na seksualne preferencije nakon toga. Homoseksualci i strejt muškarci imaju iste nivoe polnih hormona Nivoi polnih hormona su isti kod gej žena i strejt žena.)

Danas, međutim, znamo mnogo više o mozgu nego što smo znali kada se homoseksualnost smatrala bolešću koja zahtijeva liječenje, a količina znanja koja imamo o mozgu raste.

Perhaps one day we will be able to adjust sexual preference via surgery - focusing on the particular regions of the brain that are associated with sexual preference &ndash or via neural implants or training.

If Sexual Preference Can Be Changed

Even if gay people can never stop being attracted to members of the same sex, they can learn not to act on their desires.

People already learn to stop smoking, to give up certain foods, and not cheat on their husbands or wives.

If we define being gay as engaging in homosexual behavior (the concept of &ldquogay&rdquo as an identity is a Western cultural concept &ndash people who have sex with both men and women may call themselves gay, straight or bisexual, depending on the rules of their culture or subculture), then people stop being gay as soon as they stop engaging in this behavior.

If they could, should they change their brains (or have their brains changed) in order to make themselves straight?

I believe that people have the right to engage in any behavior that they choose, as long as their actions do not harm others, and I believe that gay sex and gay relationships do not cause harm to anyone. Therefore, people who are gay by choice have the right to remain that way

(Of course, there are abusive and unhealthy gay relationships that should not be tolerated, just as there are unhealthy heterosexual relationships that should not be tolerated.)

If sexual preference can be altered, then people who support gay rights can&rsquot rely on the argument that gay people should be protected from discrimination because gay people have no choice but to be gay &ndash an argument that seems like an apology for homosexuality, as if homosexuality is a disease for which there is no cure.

There is an element of homophobia in that argument&ndash the implication that gay people would become straight, if only they could. Supporting gay marriage becomes equivalent to supporting the construction of wheelchair ramps. The &ldquogays can&rsquot help being that way&rdquo approach is reminiscent of the old view of homosexuality as a psychiatric illness.

In a blog post for Slate, J. Bryan Lowder comments on Cynthia Nixon&rsquos claim that her lesbianism is a choice. Lowder agrees with Nixon that blaming biology &ldquocedes a great deal of control to bigoted people.&rdquo

You don&rsquot have to defend a controversial action by arguing that you have no control over your behavior. In fact, when we you do so, you reinforce the belief that your behavior is undesirable.

Nobody has to prove that biology forces them to vote for a particular political party, practice a certain religion or follow a particular diet.

Just as gay people who are happy as they are should not be forced to change their sexual orientation, gay people who want to be straight should have the right to change if they can &ndash and the correct word is &ldquochange&rdquo &ndash not &ldquocure&rdquo.

In his blog post, Lowder states, &ldquoMany critics will argue that appealing to biology is the only way to protect against the attacks of the religious right.&rdquo

It might make these critics unhappy to hear this, but that&rsquos not how science works.

Science doesn&rsquot change in order to support political opinions.

Scientific beliefs change as we gain new information, and sometimes science tells us things that we would rather not hear.

Bailey, J.M. & Pillard, R.C. (1991). A genetic study of male sexual orientation. Archives of General Psychiatry, 48(12): 1089&ndash1096.

Balthazart, J. (2012). Brain development and sexual orientation. Colloquium Series on the Developing Brain, Morgan & Claypool Publishers.

Boyke, J., Driemeyer, J., Gaser, C., Büchel, C. & May, A. (2008). Training induced brain structure changes in the elderly. Journal of Neuroscience, 28(28): 7031-7035.

Maguire, E.A. et al. (2000). Navigational-related structural change in the hippocampi of taxi drivers. Proceedings of the National Academy of Sciences USA, 97(8): 4398&ndash4403.

Photo credits: Vancouver Gay Pride Parade 2008 by ecodallaluna on Wikimedia Commons DNA by ynse on Wikimedia Commons Brain fMRI by NASA.

The views expressed are those of the author(s) and are not necessarily those of Scientific American.

O AUTORU(IMA)

Marcia Malory is a writer who mostly writes about science. She graduated Summa Cum Laude from Brooklyn College with a BA in Political Science, and her writing often focuses on how science affects society. She has worked in various industries on both sides of the Atlantic and now lives in York, England. You can find out more about her by visiting her website


How does smoking affect the body?

Smoking cigarettes can have many adverse effects on the body. Some of these can lead to life-threatening complications.

In fact, according to the Centers for Disease Control and Prevention (CDC) , smoking cigarettes increases the risk of dying from all causes, not just those linked to tobacco use.

Smoking cigarettes affects the respiratory system, the circulatory system, the reproductive system, the skin, and the eyes, and it increases the risk of many different cancers.

In this article, we look at 10 possible effects of smoking cigarettes.

Share on Pinterest Image credit: Stephen Kelly, 2019.

Smoking cigarettes affects lung health because a person breathes in not only nicotine but also a variety of additional chemicals.

Cigarettes are responsible for a substantial increase in the risk of developing lung cancer. This risk is 25 times greater for men and 25.7 times greater for women .

The CDC report that roughly 9 out of 10 lung cancer deaths is linked to smoking.

Smoking cigarettes also presents a greater risk of developing and dying from chronic obstructive pulmonary disorder (COPD). In fact, the American Lung Association report that smoking causes 80 percent of COPD deaths.

Cigarettes are also linked to developing emphysema and chronic bronchitis. They can also trigger or exacerbate an asthma attack.

Smoking cigarettes can damage the heart, blood vessels, and blood cells.

The chemicals and tar in cigarettes can increase a person’s risk of atherosclerosis, which is the buildup of plaque in the blood vessels. This buildup limits blood flow and can lead to dangerous blockages.

Smoking also increases the risk of peripheral artery disease (PAD), which occurs when the arteries to the arms and legs start to narrow, restricting blood flow.

Research shows a direct link between smoking and developing PAD. Even those who used to smoke face a higher risk than people who never smoked.

Having PAD increases the risk of experiencing:

Smoking cigarettes can damage a female’s reproductive system and make it more difficult to get pregnant. This may be because tobacco and the other chemicals in cigarettes affect hormone levels.

In males, the more cigarettes a person smokes and the longer they smoke for, the higher the risk of erectile dysfunction. Smoking can also affect the quality of the sperm and therefore reduce fertility.

According to the CDC , smoking can affect pregnancy and the developing fetus in several ways, including:

  • increasing the risk of ectopic pregnancy
  • reducing the baby’s birth weight
  • increasing the risk of preterm delivery
  • damaging the fetus’s lungs, brain, and central nervous system
  • increasing the risk of sudden infant death syndrome
  • contributing to congenital abnormalities, such as cleft lip or cleft palate

The CDC report that people who smoke regularly have a 30–40 percent higher risk of developing type 2 diabetes than those who do not.

Smoking can also make it more difficult for people with diabetes to manage their condition.

Smoking cigarettes can weaken a person’s immune system, making them more susceptible to illness.

It can also cause additional inflammation in the body.

Smoking cigarettes can cause eye problems, including a greater risk of cataracts and age-related macular degeneration.

Other vision problems related to smoking include:

People who smoke have double the risk of gum disease. This risk increases with the number of cigarettes a person smokes.

Symptoms of gum disease include:

  • swollen and tender gums
  • bleeding when brushing
  • loose teeth
  • sensitive teeth

Smoking tobacco can limit a person’s ability to taste and smell things properly. It can also stain the teeth yellow or brown.

Smoking tobacco can affect a person’s skin and hair. A person who smokes may experience prematurely aged, wrinkled skin. They also have a higher risk of skin cancer, “especially on the lips.”

Smoking can cause the hair and skin to smell of tobacco. It can also contribute to hair loss and balding.

In addition to the well-documented link with lung cancer, smoking cigarettes can also contribute to other forms of cancer.

The American Cancer Society report that cigarette smoking causes 20–30 percent of pancreatic cancers.

People who smoke are also three times as likely to develop bladder cancer than people who do not.

Smoking cigarettes can also double a person’s risk of stomach cancer. Tobacco is especially linked to stomach cancers that occur near the esophagus.

Cigarettes can also increase the risk of:

The ill effects of smoking cigarettes do not only affect people who smoke. Secondhand smoke can also have significant health effects on family members, friends, and coworkers.

Effects of exposure to secondhand smoke include:

  • increasing the risk of colds and ear infections
  • making asthma worse
  • raising blood pressure
  • damaging the heart
  • reducing levels of high-density lipoprotein, or “good,” cholesterol

While quitting smoking can be challenging, the CDC report that today, there are more people who used to smoke than people who currently smoke.

Once a person stops smoking, the benefits start accumulating. These include clearer skin, improved oral health, more stable hormones, a stronger immune system, and a reduced risk of many types of cancers.

Some other benefits of quitting smoking include:

  • After 20 minutes–12 hours: Heart rate and carbon monoxide in the blood drop to normal levels.
  • After 1 year: The risk of a heart attack is much lower, as is blood pressure. Coughing and upper respiratory problems begin to improve.
  • After 2–5 years: The risk of stroke drops to that of someone who does not smoke, according to the CDC .
  • After 5–15 years: The risk of mouth, throat, esophagus, and bladder cancer is reduced by half.
  • After 10 years: The risk of lung cancer and bladder cancer is half that of someone who currently smokes.
  • After 15 years: The risk of heart disease is similar to that of someone who never smoked.

Nicotine is an addictive drug and can cause withdrawal symptoms when a person stops using it. These symptoms including cravings, increased appetite, and irritability. Cravings and other effects typically subside over time.

A doctor or other healthcare professional can help a person take positive steps toward quitting smoking.


Toxic myths about vaccines

Antivaccine activists would have you believe that vaccines are loaded with “toxins” and are therefore dangerous. While there are some chemicals that sound scary in some vaccines, they dose makes the poison, and at the tiny amounts used in vaccines none of these “toxins” are harmful.

Ever since there have been vaccines, there has been an antivaccination movement. It began shortly after Edward Jenner discovered how to use the weaker cowpox virus to induce long-lasting immunity to smallpox, there has been resistance to the concept of vaccination, a resistance that continues to this very day. Reasons for this resistance have ranged from religious, to fear of injecting foreign substances, to simple resistance to the government telling people what to do. Some fear even the infitessimally small risk that vaccines pose for the benefit of resistance to disease far more than they fear the diseases themselves, a result of the very success of modern vaccines. Of course, vaccines, like any other medical intervention, are not without risks, making it easy for them to jump on any hint of harm done by vaccines, whether real or imagined, even though vaccines are among the very safest of treatments.

One of the biggest myths that antivaccinationists believe and like to use to stoke the fear of vaccines is the concept that they are full of “toxins.” The myth that mercury in the thimerosal preservative commonly used in vaccines in the U.S. until early 2002 was a major cause of autism is simply the most recent bogeyman used to try to argue that vaccines do more harm than good, as was the scare campaign engineered in response to Andrew Wakefield’s poor science claiming a link between the MMR vaccine and autism. Now that study after study have failed to find or corroborate a link between thimerosal in vaccines or vaccines in general and autism to the point where even the most zealous of zealots are having a hard time defending the claim that mercury in vaccines cause autism any more, predictably the campaign against vaccines has fallen back on the old “toxins” myth. If you peruse antivaccinationist websites, it won’t take long to find articles claiming that vaccines are full of the most terrifying and nasty toxins. Examples in the media abound as well. For example, Jenny McCarthy, comic actress and former Playboy Playmate who has been doing the talk show and publicity circuit lately to plug her book in which she claims that vaccines caused her son’s autism and that she was able to cure it with “biomedical” interventions and diet, recently gave an interview in which she said:

What I really am is “anti-toxins” in the vaccines. I do believe that there is a correlation between vaccinations and autism. I don’t think it’s the sole cause, but I think they’re triggering–it’s triggering–autism in these kids. A really great example is…is, sometimes obesity can trigger diabetes. I do believe that vaccines can trigger autism…It’s so much more than just mercury. That is one ingredient in the recipe of autism…I’m talking about all of them. I’m calling for cleaning out the toxins. People don’t realize that there is aluminum, ether, antifreeze, still mercury, in the shots…People are afraid of secondhand smoke, but they’re OK with injecting the second worst neurotoxin on the planet in newborns.

Another example of what I sometimes call the “toxin gambit” comes from Deirdre Imus, wife of shock jock Don Imus, with both husband and wife being well-known and reliable media boosters of the claim that vaccines somehow cause autism:

So, where are the evidenced based (conflict free) studies that prove the safety of these “trace” amounts and proof that there are “no biological effects” of any amount of mercury being injected into our children and pregnant moms? Also, where are the evidence based studies proving the safety of vaccines given to pregnant moms and our children that contain other toxins such as aluminum and formaldehyde?

The most recent example of this tactic comes from an organization called Generation Rescue, which just last week ran a full-page ad in USA Today, paid for in part by Jenny McCarthy and her present boyfriend Jim Carrey:

Besides being one of the most egregious examples of a post hoc ergo propter hoc fallacy that I’ve ever seen from an antivaccination site, this Generation Rescue ad demonstrates clearly a new strategy (or, more properly, a resurrection of an old technique) now that science is coming down conclusively against mercury in vaccines as a cause of autism, a strategy of propagating fear by linking vaccines with “toxins.” So what’s the real story? Are there really deadly toxins in vaccines that parents should be worried about?

To answer this question, I thought I’d use what to me is arguably the most amazingly over-the-top examples of this strategy of listing “toxins” in vaccines as a jumping off point. This example is embodied in a post by one Kent Heckenlively writing for the Age of Autism blog entitled FDA Says A-OK: Vaccine Ingredients from A to Z. This post examines a list taken straight from the CDC website of ingredients found in vaccines besides the bacterial or viral proteins designed to evoke the protective immune response and tries to scare parents about almost every one. Of course, nearly all of these comparisons fail to acknowledge that time-honored pharmacological principle that “the dose makes the poison” and extrapolate horrible consequences known to occur during prolonged exposure or exposure to large amounts to the tiny amounts in vaccines. That’s exactly what Mr. Heckenlively does to what is, I must say, a truly ridiculous level. However, as patently ridiculous as Mr. Heckenlively’s post is, I believe that it is not a straw man and still worth starting the discussion with because it serves almost as a reductio ad absurdum concentration of actual arguments that antivaccinationists make about “toxins” in vaccines. A few examples, starting with these, will readily show you what I mean:

Neomycin is used as an anti-bacterial. It is also nephrotoxic and can cause kidney damage.

Polymyxin B is used as an anti-bacterial. It binds to the cell membrane and alters its structure, making it more permeable. The resulting water uptake leads to cell death. Side effects include neurotoxicity and acute renal tubular necrosis.

Streptomycin is used as an anti-bacterial. Streptomycin stops bacterial growth by damaging cell membranes and inhibiting protein synthesis. Specifically, it binds to the 16S rRNA of the bacterial ribosome, interfering with the binding of formyl-methionyl-tRNA to the 30S subunit. This prevents initiation of protein synthesis. Humans have structurally different ribosomes from bacteria, thereby allowing the selectivity of this antibiotic for bacteria. Streptomycin cannot be given orally, but must be administered by regular intramuscular injection. An adverse effect of this medicine is oto-toxicity. It can result in permanent hearing loss.

All of this is true but highly deceptive. Zašto? The recommended dosage of streptomycin for the treatment of various infections is 20-40 mg/kg per day, for a maximum of 1 g per day! Why is this relevant? Because every vaccine given to a child during his entire life probably doesn’t even come anywhere near 1 mg, that’s why. Antibiotics like streptomycin and neomycin are used in cell culture medium at low concentrations to suppress the growth of bacteria. The reason that these antibiotics are listed is because they’re used in culturing the cells necessary to grow the viruses used in making vaccines. By the time the vaccine is made, these antibiotics are only present in trace amounts, nowhere near enough to cause renal toxicity or ototoxicity, which only occurs with use at or above the range of the doses listed above. I suspect that Mr. Heckenlively knows this too but only mentions it because he knows it will scare parents. Indeed, he takes this sort of distortion to a truly comical extreme with this example:

Sucrose is used as a stabilizer. Over-consumption of sucrose has been linked with some adverse health effects. The most common is dental caries or tooth decay, in which oral bacteria convert sugars (including sucrose) from food into acids that attack tooth enamel. When a large amount of foods that contain a high percentage of sucrose is consumed, beneficial nutrients can be displaced from the diet, which can contribute to an increased risk for chronic disease. It has been suggested that sucrose-containing drinks may be linked to the development of obesity and insulin resistance.

Does Heckenlively honestly think that the baby is eating the vaccine or that there’s kilogram upon kilogram of sucrose in vaccines? Using Mr. Heckenlively’s logic, I could say that because there’s the chelation agent EDTA used in some vaccines as a preservative babies could use it as a treatment for heavy metal poisoning. Sadly, Mr. Heckenlively is not alone in using such distortions to attack vaccines. For example, here are some even more deceptive statements on other such antivaccinationist lists as well about other vaccine ingredients:

Sodium Hydroxide (also known as lye, caustic soda, soda lye.) Is corrosive and is an Eye, skin and respiratory irritant. Can burn eyes, skin and internal organs. Can cause lung and tissue damage, blindness and can be fatal if swallowed. Found in oven cleaners, tub and tile cleaners, toilet bowl cleaners and drain openers.

Hydrochloric acid: CAN DISTROY TISSUE UPON DIRECT CONTACT! Found in aluminum cleaners and rust removers.

Neglected is the simple chemical observation that these effects depend upon the pH of these acids and bases. The reason they’re used in vaccines is to adjust the pH of the vaccine to neutral. The person who wrote these things clearly doesn’t understand the basic concept of pH. Does she honestly think that the pH of vaccines is either 0 (very acid) or 14 (very basic)? Moreover, sodium hydroxide, when it neutralizes an aqueous acid solution will simply form the sodium salt of whatever the anion was in the acid. Hydrochloric acid will form the chloride salt with whatever cation was in the base. When sodium hydroxide or hydrochloric acid are used, one to neutralize the other, the result is an NaCl solution of neutral pH: common table salt.

Of course, this list does contain a number of chemicals that do sound really scary. However, if you remember the pharmacological principle that “the dose makes the poison,” they are much less so. These chemicals are all present at extremely low concentrations in vaccines, certainly not at any dangerous levels. Moreover, some of the fearmongering about such seemingly scary toxins betrays a serious lack of understanding of basic chemistry.

Here’s one example. The aforementioned Jenny McCarthy has been repeating that there is “antifreeze” in vaccines, as she did in the interview linked to earlier. That line is straight off of a number of antivaccination websites. (Amazingly Mr. Heckenlively managed to restrain himself from repeating “the “antifreeze in vaccines” gambit. I can only hope that it is due to intellectual honesty, although I can’t rule out the possibility that he just didn’t know about it.) One website in particular links to an MSDS about Quaker State Antifreeze/Coolant, the principal ingredients of which are ethylene glycol and diethylene glycol. Guess what? There’s no ethylene or diethylene glycol in vaccines. Accurate chemistry or pharmacology never was a major concern among antivaccinationists. After all, Jenny McCarthy also says that there’s “ether” in vaccines, too. The only “ether” I could find in the CDC’s list is polyethylene glycol pisooctylphenyl ether (Triton X-100), a common detergent agent used to make cell membranes permeable. In the past, a compound called Tween-Ether was sometimes used instead of Triton X-100 it’s the same sort of thing, a fairly large organic molecule with an ether chemical group hooked on. I suspect that Jenny and most antivaccinationists are too chemistry-challenged to realize that this is not the same thing as diethyl ether, which was used as an anaesthetic agent before safer volatile agents were developed and is often commonly referred to as just “ether.” Jenny also apparently doesn’t realize that ether is not very soluble in aqueous solution. The only way I could even conceive ether being used in the vaccine manufacturing process is if it’s used for a chemical extraction, in which case, it too would be present in at best trace amounts. Moreover, this may even be one source of the claim that antifreeze is in vaccines as well. Note the first part of the chemical name: “polyethylene glycol.” It just so turns out that a major component of many antifreezes is the chemical ethylene glycol.

I also suspect that the whole “antifreeze in vaccines” canard may have derived from a claim that ethylene glycol is used in the synthesis of thimerosal. In actuality, it’s synthesized using ethyl mercuric chloride, thiosalicylic acid, sodium hydroxide and ethanol, although I don’t know if there are other methods of synthesis that do involve ethylene glycol. The origin of this claim could also come from other trace chemicals in vaccines as well, such as propylene glycol. Either way, even if there were ethylene glycol in vaccines, it would not be at a concentration anywhere near high enough to be toxic or dangerous.

Because mercury hasn’t been in most childhood vaccines for six years, one of the two most favored ingredients that antivaccinationists now like to cite is formaldehyde. Yes, that is indeed the same chemical that’s used to fix tissue for pathology (usually as a 10% solution known as formalin that contains 10 g/100 ml of formaldehyde and is buffered to a neutral pH) and the same chemical used in the embalming fluid for the cadavers we dissected as medical students. (Indeed, I still remember that smell, which was impossible to get rid of entirely during the months I took gross anatomy.) During the vaccine manufacturing process, it’s used to inactivate live virus, and traces do remain after manufacturing. Why on earth would those traces be allowed to remain? Remember again: The dose makes the poison. In trace amounts, formaldehyde is not dangerous. Also, it doesn’t last long in aqueous solution, such as vaccines. It breaks down to formic acid and carbon monoxide. Moreover, exposure to far more formaldehyde than any vaccine contains is ubiquitous in modern life. It’s in auto exhaust, and various substances found in virtually every household emit it:

Latex paint, fingernail hardener, and fingernail polish release a large amount of formaldehyde to the air. Plywood and particle board, as well as furniture and cabinets made from them, fiberglass products, new carpets, decorative laminates, and some permanent press fabrics give off a moderate amount of formaldehyde. Some paper products, such as grocery bags and paper towels, give off small amounts of formaldehyde. Because these products contain formaldehyde, you may also be exposed on the skin by touching or coming in direct contact with them. You may also be exposed to small amounts of formaldehyde in the food you eat. You are not likely to be exposed to formaldehyde in the water you drink because it does not last a long time in water.

Of course, given my background, it’s hard not to mention that every generation of medical students since time immemorial has been exposed to large amounts of formaldehyde. I’m not saying this is a good thing personally I wish I could have avoided it, and it would be a good thing if we could decrease the average exposure to it while going about our activities of life. However, it’s a matter of perspective. Antivaccinationists rant about formaldehyde in vaccines and ignore a source that is orders of magnitude greater over the lifetimes of each and every one of us from childhood to old age: the environment.

Finally, now that thimerosal has been removed from nearly all childhood vaccines, the antivaccinationists needed to find another bogeyman in vaccines to demonize, and, given their fear of heavy metals and belief that chelation therapy to remove them can cure autism, the most obvious candidate was aluminum, which has been used as an adjuvant in many vaccines for over 80 years to increase the ability of antigens to provoke the desired immune response. It has become other of the top two chemicals that antivaccinationists like to cite to demonize vaccines. True, aluminum is not nearly as scary-sounding as mercury, but with mercury falling by the wayside, antivaccinationists are certainly trying very hard to make it so, which brings us back to Mr. Heckenlively’s post:

Aluminum hydroxide, aluminum phosphate, and aluminum potassium sulfate are all used as adjuvants to stimulate the immune system. Aluminum products found in commercial antiperspirants have been linked with breast cancer. A recent article published in the Journal of Inorganic Chemistry based on research from Keele University in England was trying to explain the “known, but unaccounted for, higher incidence of tumors in the upper outer quadrant of the breast.” They found that aluminum content was higher in the outer regions where there would be the highest density of antiperspirant. In discussing aluminum’s potential danger the report stated, “Aluminum is a metalloestrogen, it is genotoxic, is bound by DNA and has been shown to be carcinogenic. It is also a pro-oxidant and this unusual property might provide a mechanistic basis for any putative carcinogenicity. The confirmed presence of aluminum in breast tissue biopsies highlights its potential as a possible factor in the etiology of breast cancer.”

I can’t help but ask here: Applying an aluminum-based compound to one’s skin over the course of many, many years is related to some injections of aluminum-based adjuvants in vaccines exactly…how? Of course, the above claim is a total nonsequitur, but what about the frequent confident claims on antivaccination websites that aluminum causes Alzheimer’s disease and that by implication vaccines cause Alzheimer’s? This is a claim by well-known antivaccinationist Hugh Fudenberg, who is often quoted thusly:

According to Hugh Fudenberg, MD (http://members.aol.com/nitrf), the world’s leading immunogeneticist and 13th most quoted biologist of our times (nearly 850 papers in peer review journals), if an individual has had five consecutive flu shots between 1970 and 1980 (the years studied) his/her chances of getting Alzheimer’s Disease is ten times higher than if they had one, two or no shots. I asked Dr. Fudenberg why this was so and he said it was due to the mercury and aluminum that is in every flu shot (and most childhood shots). The gradual mercury and aluminum buildup in the brain causes cognitive dysfunction. Is that why Alzheimer’s is expected to quadruple? Notes: Recorded from Dr. Fudenberg’s speech at the NVIC International Vaccine Conference, Arlington, VA September, 1997. Quoted with permission. Alzheimer’s to quadruple statement is from John’s Hopkins Newsletter Nov 1998.

Not surprisingly, this claim is not supported by science. There’s no good evidence that the flu vaccine is associated with an increased incidence of Alzheimer’s. Indeed, on his personal blog, my co-blogger Steve Novella has nicely summarized the evidence regarding whether or not aluminum is involved in the pathogenesis of Alzheimer’s disease, concluding:

The evidence of aluminum and AD is mixed, without a clear direction. At present the best answer we have is that aluminum probably does not cause AD but appears to be playing some role, perhaps influencing severity. But even after 42 years, there remains a question mark next to these conclusions. We can rule out that aluminum is the single cause of AD, but whether or not it is an independent risk factor is a qualified “probably not.”

And, most importantly, Steve said this about how the science looking at whether aluminum causes Alzheimer’s disease or not is abused:

The mainstream scientific and patient or disease-oriented groups accurately reflect the above interpretation of the research. But the complexity of the results make it very easy to exploit for the purpose of fear-mongering. The notorious crank website, Rense.com, for example, cherry picks the evidence that suggests there is a correlation and piles it up to present a very distorted view of the issue. There will likely persist rumors, scare e-mails, and conspiracy websites promoting the idea that aluminum causes AD regardless of how the research progresses.

Now the antivaccinationists are climbing aboard the aluminum scare train as well because the scientific evidence is becoming so clear that their previous favorite bogeyman vaccine ingredient, thimerosal, is not associated with autism that even the die-hards are having a hard time arguing that it is anymore, particularly now that thimerosal is no longer present above trace amounts in most childhood vaccines. Consequently, they have no choice but to branch out to other scary-sounding ingredients in vaccines and invoking vague (and, conveniently enough, almost impossible to demonstrate) “environmental toxins” or risk becoming irrelevant.

One thing that you have to remember about resistance to vaccines by groups like Generation Rescue, SafeMinds, and others is that it is not scientific in nature. It is either due to an excessive reliance on anecdotes or confusing correlation with causation (usually with a distrust of science and medicine), or it is ideological in nature. No matter how many of the “toxins” scientists remove from vaccines, it will never be enough for Generation Rescue, Jenny McCarthy, or other antivaccinationists, because it’s all about the vaccines and the very concept of vaccination itself, not any individual ingredients in the vaccines. Antivaccinationists will never come to a point where they say, “OK, now I believe that all the toxins are gone and vaccines are safe.” They’ll either fixate on the viruses or the viral or bacterial antigens themselves, or they’ll make the claim that vaccines are made using “aborted fetuses” because some cell lines used to grow up virus stocks were derived from aborted fetuses 40 or more years ago. If every trace of formaldehyde, aluminum, or any other chemical with more than two syllables in its name were somehow to be removed from all vaccines, they would still be saying things like this:

It is the toxin, or germ, contained in the shot itself that causes the adverse affects on the immune system.

Dead-virus, or live-virus vaccine etc…who cares? The cultures for polio vaccines are grown in the kidney tissue of dead monkeys in third-world countries with little or no controls and the virulent pustule toxin is put in vaccines to be shot into you little kid’s arm. I wouldn’t go into a room where that putrid stuff is, let alone inject it into my blood stream! Would you?

This DNA is from such organisms as various animals, animal/human viruses, fungi and bacteria. It has been documented that the injecting foreign DNA can cause it or some of it to be incorporated into the recipient’s DNA (see ‘Immunisation’ Against Diseases for Children). Remember, nature has not experienced such a direct invasion as this before, so can you be sure that it would have developed a way to protect your body against it?

That pretty much rules out any live attenuated virus vaccine for such an antivaccinationist, doesn’t it? Even worse is this:

The human blood is supposed to be, and traditionally was, sterile – no bacteria (or other organisms) present in it. That is not the case any more. Naturally this has a weakening effect on the immune system, apart from sometimes leading to severe bacterial infections.

No live bacteria is in a vaccine. It is possible, as with any injection, for vaccines to become contaminated with bacteria (which is one reason why preservatives like thimerosal were used for multidose vials, where reuse increases the risk of bacterial contamination), but that is not the intent. What is in vaccines are bacterial proteins, which contain the antigens necessary to provoke the desired immune response.

It would be fascinating to engage an antivaccinationist who makes the claim that he is not “antivaccine” but “antitoxin” or “pro-vaccine safety” in a discussion and ask him this hypothetical question: If formaldehyde, “antifreeze,” aluminum, thimerosal, and every chemical in vaccines circulating in all those lists on antivaccination websites that so frighten you were somehow absolutely removed from the standard childhood vaccines so that not a single molecular remained, would you then vaccinate your child? The only thing that would remain is buffered salt water and the necessary antigens, be they killed virus or bacterial proteins, or whatever.

My guess is that nearly all antivaccinationists would say no, because it’s the “toxin” that makes vaccines work that really disturbs them, as the quotes above clearly demonstrate. Remember that when you see these lists circulating on antivaccinist websites. Remember, too, the principle that the dose makes the poison. Only then will you understand how toxic the myths about vaccines being peddled by antivaccinationists are.


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