Vitamin A: Izibonelelo, ukuswela, ukuTyhefu kunye nokunye

Umxholo

• Yintoni ivithamin A?
• Imisebenzi kwiQumrhu lakho
• Izibonelelo zezeMpilo
• I-Antioxidant enamandla
• Ibalulekile kwimpilo yamehlo kwaye ithintela ukuvela kweMacular
• Ngamana unokuzikhusela ngokuchasene noMhlaza othile
• Kubalulekile ekuchumeni nasekukhuleni komntwana
• Ukunyusa inkqubo yakho yokuzikhusela
• Ukusilela
• Imithombo yokutya
• Iingcebiso ngeTyhefu kunye neDosi
• Umgca osezantsi

I-Vitamin A sisakha-mzimba esinyibilikayo esidlala indima ebalulekileyo emzimbeni wakho.

Kukho ngokwendalo ekutyeni okutyayo kwaye kunokugqitywa ngokutya.

Eli nqaku lixoxa ngevithamini A, kubandakanya izibonelelo zayo, imithombo yokutya, kunye nefuthe lokusilela kunye nobutyhefu.

Yintoni ivithamin A?

Nangona ivithamin A ihlala ithathwa njengesicuku sinye, ligama leqela elinemixube enamafutha, kubandakanya i-retinol, i-retinal kunye ne-retinyl esters ().

Zimbini iintlobo zevithamini A ezifumaneka ekutyeni.

I-vitamin A esele yenziwe ngaphambili - i-retinol kunye ne-retinyl esters- yenzeka kuphela kwiimveliso zezilwanyana, ezinje ngobisi, isibindi kunye nentlanzi, ngelixa i-provitamin A carotenoids zininzi kukutya kwezityalo njengeziqhamo, imifuno kunye neoyile ().

Ukuyisebenzisa, umzimba wakho kufuneka uguqule zombini iifom ze-vitamin A kwi-retinal kunye ne-retinoic acid, iifom ze-vitamin.

Ngenxa yokuba ivithamini A inyibilika ngamanqatha, igcinwa kwizicubu zomzimba ukuze zisetyenziswe kamva.

Uninzi lwevithamini A emzimbeni wakho lugcinwa kwisibindi sakho ngohlobo lwe-retinyl esters ().

Ezi esters ziye zaphulwe phantsi kuyo yonke i-trans-retinol, ebophelela kwiprotein yokubopha ye-retinol (RBP). Emva koko ingena kwigazi lakho, apho umzimba wakho unokuyisebenzisa ().

I-Vitamin A ligama elenziwe lafana neliqhelekileyo kwiqela leemveliso ezinyibilikayo ezinamafutha ezifumaneka kwizilwanyana nakwizityalo zokutya.

Imisebenzi kwiQumrhu lakho

I-Vitamin A ibalulekile kwimpilo yakho, ixhasa ukukhula kweseli, ukusebenza komzimba, ukukhula komntwana kunye nombono.

Mhlawumbi omnye wemisebenzi eyaziwayo yivithamini A yindima yayo kumbono nakwimpilo yamehlo.

I-Retinal, uhlobo olusebenzayo lwevithamini A, idityaniswa neprotein opsin ukwenza i-rhodopsin, imolekyuli eyimfuneko kumbono wombala kunye nombono wokukhanya okuncinci ().

Ikwanceda ukukhusela kunye nokugcina i-cornea- ungqimba olungaphandle lweliso lakho- kunye nesihlanganisi - inwebu ecekeceke egubungela umphezulu wamehlo akho nangaphakathi kweenkophe zakho ().

Ukongeza, ivithamini A inceda ukugcina izicwili zomhlaba ezifana nolusu, amathumbu, imiphunga, isinyi kunye nendlebe yangaphakathi.

Ixhasa ukusebenza kwamajoni omzimba ngokuxhasa ukukhula kunye nokusasazwa kweeseli ze-T, uhlobo lweseli emhlophe yegazi ekhusela umzimba wakho kukosuleleka ().

Ngaphezu koko, ivithamini A ixhasa iiseli ezinempilo zolusu, ukuzala kwendoda nebhinqa kunye nokukhula komntwana ().

I-Vitamin A iyafuneka kwimpilo yamehlo, umbono, ukusebenza komzimba, ukukhula kweeseli, ukuzala kunye nokukhula komntwana.

Izibonelelo zezeMpilo

Vitamin A sisondlo esibalulekileyo esixhamla impilo ngeendlela ezininzi.

I-Antioxidant enamandla

I-Provitamin A carotenoids enjenge-beta-carotene, i-alpha-carotene kunye ne-beta-cryptoxanthin zingaphambi kwe-vitamin A kwaye zineempawu zokulwa ne-antioxidant.

IiCarotenoids zilwa nee-radicals zasimahla- iimolekyuli ezisebenzayo ezinokuthi zonakalise umzimba wakho ngokwenza uxinzelelo lwe-oxidative ().

Uxinzelelo lwe-oxidative lunxulunyaniswe nezifo ezingapheliyo ezinje ngesifo seswekile, umhlaza, isifo sentliziyo kunye nokwehla kwengqondo ().

Ukutya okuphezulu kwii-carotenoids kunxulunyaniswa nomngcipheko ophantsi uninzi lwezi meko, ezinjengesifo sentliziyo, umhlaza wemiphunga nesifo seswekile (,,).

Ibalulekile kwimpilo yamehlo kwaye ithintela ukuvela kweMacular

Njengoko sele kukhankanyiwe apha ngasentla, ivithamin A ibalulekile kumbono nakwimpilo yamehlo.

Ukutya okwaneleyo ukutya i-vitamin A kunceda ukukhusela kwizifo ezithile zamehlo, ezinje ngokuhla kwe-macular degeneration (AMD).

Izifundo zibonisa ukuba amanqanaba aphezulu egazi e-beta-carotene, i-alpha-carotene kunye ne-beta-cryptoxanthin inokuwunciphisa umngcipheko we-AMD ukuya kuthi ga kwi-25% ().

Oku kuncitshiswa komngcipheko kunxulunyaniswa nokukhuselwa kwezakha mzimba ze-carotenoid ngokunciphisa amanqanaba oxinzelelo lwe-oxidative.

Ngamana unokuzikhusela ngokuchasene noMhlaza othile

Ngenxa yeempawu zabo zokulwa ne-antioxidant, iziqhamo kunye nemifuno enotye kakhulu ye-carotenoid inokukhusela kwiintlobo ezithile zomhlaza.

Umzekelo, uphononongo kubantu abadala abangaphezulu kwe-10 000 bagqiba kwelokuba abantu abatshayayo abanamanqanaba aphezulu egazi e-alpha-carotene kunye ne-beta-cryptoxanthin babenomngcipheko ophantsi wama-46% kunye nama-61% wokufa ngenxa yomhlaza wemiphunga, ngokwahlukeneyo, kunabo bangatshayiyo kwezi zondlo ().

Ngaphezulu, izifundo zetyhubhu yovavanyo zibonisa ukuba i-retinoids inokuthintela ukukhula kweeseli ezithile zomhlaza, ezinje ngesinyi, umhlaza webele kunye nomhlaza we-ovari ().

Kubalulekile ekuchumeni nasekukhuleni komntwana

I-Vitamin A ibalulekile ekuveliseni kwabesilisa nabasetyhini kuba idlala indima ekukhuleni kwesidoda kunye neqanda.

Kukwabalulekile kwimpilo yomntwana, ukukhula kwezicubu zomntwana kunye nokuzigcina, kunye nokukhula komntwana ().

Ke ngoko, ivithamini A iyadibana nakwimpilo yoomama neyomntwana nakwabo bazama ukukhulelwa.

Ukunyusa inkqubo yakho yokuzikhusela

I-Vitamin A ichaphazela impilo yomzimba ngokukhuthaza iimpendulo ezikhusela umzimba wakho kwizifo nakwizifo.

I-Vitamin A iyabandakanyeka ekwenziweni kweeseli ezithile, kubandakanya i-B kunye ne-T-seli, ezidlala indima ephambili kwiimpendulo zomzimba ezikhusela izifo.

Ukusilela kwesi sondlo kukhokelela kumanqanaba anyukayo eemolekyuli ezichasayo ezinciphisa impendulo yomzimba kunye nomsebenzi ().

I-Vitamin A ichaphazela impilo ngokugcina uxinzelelo lwe-oxidative, ukonyusa amajoni akho omzimba kunye nokukhusela kwizifo ezithile.

Ukusilela

Nangona ukunqongophala kukavithamini A kunqabile kumazwe ahambele phambili njenge-US, kuqhelekile kumazwe asaphuhlayo, njengoko aba bantu banokuba nokufikelela okulinganiselweyo kwimithombo yokutya ye-vitamin A esele yenziwe kunye ne-provitamin A carotenoids.

Ukunqongophala kukaVitamin A kungakhokelela kubunzima bempilo.

Ngokwe-WHO, ukunqongophala kukavithamini A ngoyena nobangela uphambili wokungathintelwa kwabantwana kwihlabathi liphela.

Ukunqongophala kukaVitamin A kukonyusa ubuzaza kunye nomngcipheko wokufa usulelo olufana nemasisi kunye norhudo (,).

Ukongeza, ukuswela i-vitamin A kuphakamisa umngcipheko we-anemia kunye nokufa kwabafazi abakhulelweyo kunye nefuthe elibi kwimveku ngokunciphisa ukukhula kunye nophuhliso ().

Iimpawu ezinqabileyo zokunqongophala kukavithamini A zibandakanya imiba yolusu efana ne-hyperkeratosis kunye ne-acne (,).

Amaqela athile anjengeentsana ezizelwe ngaphambi kwexesha, abantu abane-cystic fibrosis kunye nabasetyhini abakhulelweyo okanye abancancisayo kumazwe asaphuhlayo basemngciphekweni wokuswela i-vitamin A ().

Ukusilela kweVitamin A kunokukhokelela kubumfama, ukwanda kwengozi yosulelo, iingxaki zokukhulelwa kunye nemicimbi yolusu.

Imithombo yokutya

Kukho imithombo emininzi yokutya zombini ivithamin A esele yenziwe kunye neprovitamin A carotenoids.

I-vitamin A eyenziwe kwangaphambili ifunxwa ngokulula kwaye isetyenziswe ngumzimba wakho kunemithombo esekwe kwisityalo se-provitamin A carotenoids.

Amandla omzimba wakho okuguqula ngokufanelekileyo i-carotenoids, njenge-beta-carotene, kwi-vitamin A esebenzayo kuxhomekeke kwizinto ezininzi-kubandakanya i-genetics, ukutya, impilo yonke kunye namayeza ().

Ngesi sizathu, abo balandela ukutya okusekwe kwizityalo-ngakumbi ii-vegans- kufuneka baphaphe malunga nokufumana ukutya okwaneleyo okunotye kwe-carotenoid.

Ukutya okuphezulu kwi-vitamin A esele yenziwe:

• Izikhupha zamaqanda
• Isibindi senkomo
• Isibindi
• Ibhotolo
• Ikhowudi yeoyile yesibindi
• Inkukhu yesibindi
• Islamoni
• I-Cheddar ushizi
• Isoseji yesibindi
• Kumkani mackerel
• Umqala

Ukutya okuphezulu kwipritamin I-carotenoids enjenge-beta-carotene ibandakanya (25, 26):

• Iibhatata
• Ithanga
• Iminqathe
• Kale
• Ispinatshi
• Imifuno yeDandelion
• Ikhaphetshu
• I-chard yaseSwitzerland
• Ipelepele ebomvu
• Imifuno yeCollard
• Kancinci
• Ithanga leskwashi

I-vitamin A eyenziwe kwangaphambili ikhona kukutya kwezilwanyana okufana nesibindi, isalmon kunye neeqanda, ngelixa i-provitamin A carotenoids ifumaneka kukutya kwezityalo, kubandakanya ibhatata, i-kale kunye nekhaphetshu.

Iingcebiso ngeTyhefu kunye neDosi

Njengokuba ukunqongophala kukavithamini A kunokuba nefuthe elibi kwimpilo, ukufumana okuninzi kunokuba yingozi.

Isibonelelo semihla ngemihla esicetyiswayo (i-RDA) se-vitamin A yi-900 mcg kunye ne-700 mcg ngemini yamadoda nabasetyhini, ngokulandelelana-enokuthi ifikeleleke ngokulula ngokutya ukutya okupheleleyo (27).

Nangona kunjalo, kubalulekile ukuba ungagqithi kumda ongaphezulu onokunyamezeleka (UL) we-10,000 IU (3,000 mcg) yabantu abadala ukuthintela ityhefu (27).

Nangona kunokwenzeka ukuba utye u-vitamin A ogqityiweyo ngaphambili kwimithombo esekwe kwizilwanyana ezinjengesibindi, ityhefu ixhaphake kakhulu kukutya ukutya okuninzi kunye nokunyanga ngamayeza athile, afana ne-Isotretinoin (,).

Kuba i-vitamin A inyibilika ngamanqatha, igcinwe emzimbeni wakho kwaye inokufikelela kumanqanaba angenampilo ekuhambeni kwexesha.

Ukuthatha ivithamin A kakhulu kunokukhokelela kwiziphumo ebezingalindelekanga ezibi kwaye kunokuba nokubulala xa kufakwe idosi ephezulu kakhulu.

I-Vitamin A enetyhefu enobuthi yenzeka ngaphezulu kwexesha elifutshane xa idosi enye, ephezulu kakhulu ivithamin A isetyenziswa, ngelixa ityhefu engapheliyo yenzeka xa idosi ngaphezulu kwamaxesha e-10 i-RDA ifakwa ixesha elide ().

Iziphumo zixhaphakileyo zevithamini A enetyhefu- edla ngokubizwa ngokuba yihypervitaminosis A- ibandakanya:

• Ukuphazamiseka kombono
• Intlungu edibeneyo kunye nethambo
• Ukutya okungafanelekanga
• Isicaphucaphu nokugabha
• Ukuziva kwelanga
• Ukulahleka kweenwele
• Intloko ebuhlungu
• Ulusu olomileyo
• Umonakalo wesibindi
• I-jaundice
• Ukukhula okulibazisekileyo
• Ukunciphisa ukutya
• Ukudideka
• Ulusu olurhawuzayo

Nangona ingaqhelekanga kunetyhefu enganyangekiyo yevithamini A, ivithamini A enetyhefu enxulunyaniswa nokunxulumana neempawu ezibi, kubandakanya ukonakala kwesibindi, ukonyuka koxinzelelo lwe-cranial kunye nokufa ().

Ngaphezu koko, ivithamin A yetyhefu inokuba nefuthe elibi kwimpilo yoomama neyomntwana kwaye inokukhokelela kwiziphene zokuzalwa ().

Ukuthintela ityhefu, cima isongezelelo sedosi ephezulu yevithamini A.

I-UL ye-vitamin A isebenza kwimithombo yokutya esekwe kwizilwanyana kwi-vitamin A, kunye ne-vitamin A.

Ukutya kakhulu i-carotenoids yokutya ayinxulunyaniswa nobutyhefu, nangona izifundo zidibanisa izongezo ze-beta-carotene ngomngcipheko okhulayo womhlaza wemiphunga kunye nesifo sentliziyo kubantu abatshayayo ().

Kuba i-vitamin A eninzi kunokuba yingozi, qhagamshelana nogqirha wakho ngaphambi kokuba uthathe izongezo ze-vitamin A.

I-Vitamin A ityhefu inokubangela iimpawu, ezinjengokonakala kwesibindi, ukuphazamiseka kombono, isicaphucaphu kunye nokufa. Umthamo ophezulu wevithamini A kufuneka uthintelwe ngaphandle kokuba ugqirha ugqirha.

Umgca osezantsi

I-Vitamin A sisondlo esinyibilikayo esinamafutha esibalulekile ekusebenzeni kwamajoni omzimba, impilo yamehlo, ukuzala kwakhona kunye nokukhula komntwana.

Zombini ukunqongophala kunye nentsalela yokutya kunokubangela iziphumo ebezingalindelekanga ezibi, ke ngelixa kubalulekile ukudibana ne-RDA ye-700-900 mcg mihla le yabantu abadala, ungagqithi kumda ophezulu wemihla ngemihla we-3,000 mcg.

Ukutya okunempilo, okunezakha-mzimba ezifanelekileyo yindlela yokubonelela umzimba wakho ngenani elikhuselekileyo lale nto ibalulekileyo.