Hauv tib neeg lub cev,vitamin Amuaj nyob rau hauv peb hom: retinol, retinal, thiab retinoic acid. Vitamin A feem ntau tshwm nyob rau hauv daim ntawv ntawm retinol nyob rau hauv daim siab thiab cov ntshav; nyob rau hauv lub qhov muag tsuas yog nyob rau hauv daim ntawv ntawm retinal; Thaum lawv tswj cov noob qhia hauv cov hlwb thiab tswj lub neej voj voog ntawm cov hlwb, lawv feem ntau tshwm sim hauv daim ntawv ntawm retinoic acid. (qhov no yog daim ntawv kawg thiab tsis tuaj yeem hloov rov qab mus rau lwm qhov).
Cov vitamin A uas peb noj (hauv cov khoom noj tsiaj) zoo li yog retinyl esters (kev sib xyaw ntawm fatty acids thiab retinols xws li retinyl palmitate, retinyl acetate), uas hloov mus rau hauv retinol hauv lub cev. Cov zaub mov cog tsis muaj vitamin A kiag li, tab sis muaj lwm qhov sib xyaw: carotenoids. Carotenoids yog ib chav loj ntawm cov tebchaw nrog ntau tshaj 600 cov tswv cuab, xws li alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, canthaxanthin, lutein, zeaxanthin. Peb tuaj yeem tsim cov vitamin A (retinal) hauv lub cev tau zoo nyob rau hauv thawj peb carotenoids, tshwj xeeb tshaj yog beta-carotene.
Peb hom vitamin A | |||
Khoom noj khoom haus | Retinyl esters muaj | Carotenoids | |
(Cov khoom noj tsiaj) | (Cov khoom noj cog) | ||
Lub cev | Retinol | Retinal | Retinoic acid |
Kev khaws cia thiab kev thauj mus los | Kev pom kev ua haujlwm | Gene qhia | |
Qhov chaw ntawm Vitamin A
Vitamin A tsuas muaj nyob rau hauv cov tsiaj, nroj tsuag tsis muaj vitamin A, tab sis muaj pro-vitamin A (precursor) - carotene (C40H56)
Cov zaub ntsuab ntsuab yog nplua nuj nyob rau hauv vitamin A, tab sis yooj yim muaj nyob rau hauv retinol (cov ntaub ntawv nquag ntawm vitamin A) tsuas yog los ntawm cov tsiaj. Qhov chaw nplua nuj ntawm retinol yog: cov nqaij hauv nruab nrog cev; fatty ntses xws li herring thiab salmon thiab ntses roj; butter, mis nyuj thiab cheese; qe. Tib lub sijhawm, cov zaub mov cog kuj muaj carotenoids, uas yog cov tshuaj antioxidant ntawm vitamin A uas hloov mus rau hauv retinol hauv lub cev. Carotenoid-nplua nuj cog zaub mov muaj xws li: squash, carrots, thiab lwm yam txiv kab ntxwv zaub; broccoli, spinach, turnip zaub, thiab lwm yam nplooj ntsuab tsaus; qos yaj ywm qab zib; thiab txiv kab ntxwv txiv hmab txiv ntoo xws li cantaloupe, papaya, thiab txiv nkhaus taw.