Ngokunokwenzeka, ama-nitrate awahlotshaniswa nesidlo sakusihlwa, kodwa avusa imicabango mayelana nezifundo zamakhemikhali esikoleni noma umanyolo. Uma ucabanga nge-nitrate kumongo wokudla, isithombe esibi kakhulu esifika engqondweni ukuthi enyameni egayiwe kanye nemifino emisha, ama-nitrate angama-carcinogenic compounds. Kodwa ziyini ngempela futhi zihlale ziyingozi?
Eqinisweni, ukuxhumana phakathi kwe-nitrites/nitrate nempilo kucashe kakhulu kunokuthi “kubi kithi”. Isibonelo, okuqukethwe okuphezulu kwe-nitrate yemvelo yejusi ye-beetroot kuye kwaxhunyaniswa nokunciphisa umfutho wegazi kanye nokusebenza komzimba okwandisiwe. I-nitrate nayo iyisithako esisebenzayo kweminye imithi ye-angina.
Ingabe ama-nitrate nama-nitrate ayingozi ngempela kithi?
Ama-nitrate nama-nitrites, afana ne-potassium nitrate ne-sodium nitrite, ayenzeka ngokwemvelo amakhemikhali aqukethe i-nitrogen nomoya-mpilo. Kuma-nitrate, i-nitrogen iboshelwa kuma-athomu amathathu omoya-mpilo, kuthi kuma-nitrites, kube amabili. Zombili ziyizilondolozi ezisemthethweni ezivimbela amagciwane ayingozi kubhekeni, i-ham, i-salami, noshizi abathile.
Kodwa empeleni, cishe u-5% kuphela we-nitrate ekudleni okujwayelekile kwaseYurophu avela enyameni, ngaphezu kwama-80% emifino. Imifino ithola ama-nitrate nama-nitrites emhlabathini lapho ikhula khona. Ama-nitrate ayingxenye yediphozithi yemvelo yamaminerali, kuyilapho ama-nitrites akhiwa ama-microorganisms enhlabathini adiliza izinto zezilwane.
Imifino enamahlamvu efana nesipinashi kanye ne-arugula ijwayele ukuba yizitshalo eziphezulu ze-nitrate. Eminye imithombo ecebile isilimo esidliwayo esinamagatsha anamanzi kanye nejusi yebhitrudi, kanye nezaqathi. Imifino etshalwe ngokwemvelo ingase ibe namazinga aphansi e-nitrate ngoba ayisebenzisi umanyolo we-nitrate yokwenziwa.
Kodwa-ke, kunomehluko obalulekile phakathi lapho kutholakala khona ama-nitrate nama-nitrites: inyama noma imifino. Lokhu kuthinta noma ngabe i-carcinogenic.
Ukuhlangana nomdlavuza
Ama-nitrate ngokwawo awasebenzi kahle, okusho ukuthi mancane amathuba okuba ahileleke ekuphenduleni kwamakhemikhali emzimbeni. Kodwa ama-nitrites namakhemikhali abawakhiqizayo asebenza kakhulu.
Ama-nitrites amaningi esihlangana nawo awadliwe ngokuqondile, kodwa aguqulwa ama-nitrate ngamabhaktheriya emlonyeni. Ngokuthakazelisayo, ucwaningo lubonisa ukuthi ukusetshenziswa kwe-mouthwash elwa namagciwane kunganciphisa ukukhiqizwa kwe-nitrite yomlomo.
Lapho ama-nitrites akhiqizwa emlonyeni wethu egwinywa, enza ama-nitrosamine endaweni ene-asidi yesisu, amanye awo anomdlavuza futhi ahlotshaniswa nomdlavuza wamathumbu. Kodwa lokhu kudinga umthombo wama-amine, amakhemikhali atholakala ngobuningi ekudleni kwamaprotheni. Ama-nitrosamine angabuye adalwe ngqo ekudleni ngokupheka emazingeni okushisa aphezulu, njengokuthosa ubhekeni.
“Ama-nitrate/nitrites ane-carcinogenic awabaningi, kodwa indlela alungiswa ngayo nendawo yawo kuyisici esibalulekile. Isibonelo, ama-nitrite enyameni egayiwe asondelene namaprotheni. Ikakhulukazi kuma-amino acid. Lapho ziphekwe emazingeni okushisa aphakeme, lokhu kuzivumela ukuba zenze kalula ama-nitrosamine abangela umdlavuza,” kusho uKeith Allen, umqondisi omkhulu wesayensi nobudlelwane bomphakathi we-World Cancer Research Foundation.
Kodwa u-Allen wengeza ngokuthi ama-nitrites angesinye sezizathu ezenza inyama egayiwe ikhuthaze umdlavuza wamathumbu, futhi ukubaluleka kwawo akuqinisekisiwe. Ezinye izici ezingase zibe nomthelela zihlanganisa okusansimbi, ama-polycyclic anuka kamnandi e-polycyclic akheka enyameni ebhenywayo, nama-heterocyclic amines adaleka lapho inyama iphekwe phezu kwamalangabi avulekile, abuye abe nomthelela emathumbani.
Amakhemikhali amahle
Ama-nitrites awabi kangako. Kunobufakazi obukhulayo bezinzuzo zabo ohlelweni lwenhliziyo nemithambo yegazi nangale kwalokho, ngenxa ye-nitric oxide.
Ngo-1998, ososayensi abathathu baseMelika bathola uMklomelo KaNobel ngokuthola kwabo mayelana nendima ye-nitric oxide ohlelweni lwenhliziyo nemithambo yegazi. Manje siyazi ukuthi ivula imithambo yegazi, yehlise umfutho wegazi, futhi ilwe nezifo. Ikhono lokukhiqiza i-nitric oxide liye laxhunyaniswa nesifo senhliziyo, isifo sikashukela, kanye nokungasebenzi kahle kwe-erectile.
Enye indlela umzimba okhiqiza ngayo i-nitric oxide ngokusebenzisa i-amino acid ebizwa ngokuthi i-arginine. Kodwa manje sekuyaziwa ukuthi i-nitrate ingaba nomthelela omkhulu ekwakhekeni kwe-nitric oxide. Siyazi futhi ukuthi lokhu kungase kubaluleke kakhulu kubantu abadala, njengoba ukukhiqizwa kwe-nitric oxide yemvelo nge-arginine kuvame ukwehla ngokuguga.
Kodwa-ke, ngenkathi ama-nitrate atholakala ku-ham afana namakhemikhali nalawo ongase uwadle ngesaladi, asekelwe ezitshalweni angcono kakhulu.
"Sibone ukwanda kwezingozi ezihlobene ne-nitrate ne-nitrite evela enyameni kwamanye ama-cancer, kodwa asizange sibone izingozi ezihlobene ne-nitrate noma i-nitrite evela emifino. Okungenani ezifundweni ezinkulu zokubheka lapho ukusetshenziswa kulinganiselwa kuhlu lwemibuzo lokuzibika, "kusho u-Amanda Cross, uthisha wezifo zomdlavuza e-Imperial College London.
U-Cross wengeza ngokuthi "ukucabangela okunengqondo" ukuthi i-nitrate emifino enamaqabunga ayinabungozi kangako. Lokhu kungenxa yokuthi acebile ngamaprotheni futhi aqukethe nezakhi zokuzivikela: uvithamini C, ama-polyphenols kanye nemicu enciphisa ukwakheka kwe-nitrosamine. Ngakho-ke lapho iningi lama-nitrate ekudleni kwethu livela emifino futhi liphinde likhuthaze ukwakheka kwe-nitric oxide, cishe ayasilungele.
Omunye uchwepheshe we-nitric oxide waqhubekela phambili, ephikisa ngokuthi abaningi bethu bashoda ngama-nitrate/nitrites futhi kufanele bahlukaniswe njengezakhi ezibalulekile ezingasiza ekuvimbeleni ukuhlaselwa yinhliziyo nokushaywa unhlangothi.
Inani elilungile
Cishe akunakwenzeka ukulinganisa ngokuthembekile ukudla okudlayo kwe-nitrate ngoba amazinga okudla e-nitrate ayahlukahluka kakhulu. “Amazinga angashintsha izikhathi eziyishumi. Lokhu kusho ukuthi izifundo ezihlola imiphumela yezempilo ye-nitrate kufanele zihunyushwe ngokucophelela, njengoba “i-nitrate” ingase ibe umaka wokusetshenziswa kwemifino,” kusho isazi sezifo ezithinta umsoco uGünther Kulne wase-University of Reading e-UK.
Umbiko wango-2017 we-European Food Safety Authority ugunyaze inani elamukelekayo lansuku zonke elingadliwa impilo yonke ngaphandle kwengozi yezempilo ebabazekayo. Ilingana no-235 mg we-nitrate kumuntu ongu-63,5 kg. Kodwa umbiko uphawula nokuthi abantu bazo zonke ubudala bangakwazi ukweqa leli nani kalula.
Ukuthathwa kwe-nitrite ngokuvamile kuphansi kakhulu (isilinganiso sokuthathwa kwe-UK singu-1,5mg ngosuku) futhi I-European Food Safety Authority ibika ukuthi ukuchayeka kuma-preservatives e-nitrite kungaphakathi kwemikhawulo ephephile yazo zonke izakhamuzi zase-Europe, ngaphandle kokweqisa kancane. ezinganeni ezidla ukudla okunezithako zokudla eziningi.
Abanye ochwepheshe baphikisa ngokuthi isibonelelo sansuku zonke se-nitrate/nitrites siphelelwe yisikhathi noma kunjalo, nokuthi amazinga aphezulu awaphephile nje kuphela, kodwa anenzuzo uma evela emifino kunenyama egayiwe.
Kutholakale ukuthi ukuthathwa kwe-300-400 mg ye-nitrate kuhlotshaniswa nokwehla komfutho wegazi. Lesi silinganiso singatholakala kusaladi eyodwa enkulu ene-arugula nesipinashi, noma kujusi ye-beetroot.
Ekugcineni, ukuthi uphuza ushevu noma umuthi kuncike, njengenjwayelo, esikalini. I-2-9 grams (2000-9000 mg) ye-nitrate ingaba yingozi kakhulu, ithinte i-hemoglobin. Kodwa lelo nani kunzima ukulithola ngesikhathi esisodwa futhi mancane amathuba okuthi liphume ekudleni ngokwako, kunalokho liphuma emanzini anomanyolo.
Ngakho-ke, uma uzithola emifino kanye namakhambi, khona-ke izinzuzo ze-nitrate ne-nitrate cishe zingaphezu kokubi.