(1) ultraviolet hluav taws xob yog qhov naj npawb ib tus neeg tua ntawm pob. Feem ntau, cov tso nyiaj melanin tshwm sim los ntawm lub hnub raug tshem tawm nrog lub cev' s metabolism, tab sis qee tus neeg yuav muaj cov metabolism qeeb qeeb los yog hnub nyoog laus dua, tawm ntawm melanin thiab ua rau tsaus nti. Cov.
(2) Cov tshuaj lom hlau yog tshwm sim los ntawm kev siv cov tshuaj pleev ib ce tas sij hawm lossis qis tshaj, xws li cov hlau lead, mercury, thiab arsenic lom.
(3) Thaum cev nqaij daim tawv raug mob, txawv teb chaws lub cev xws li cov plua plav thiab kua mem hauv lub qhov txhab; kev siv ntawm iodine, ntshav kua txiv; lossis noj cov khoom noj uas muaj cov xim, xws li cov kua ntses, taum pauv dub, thiab lwm yam, yuav ua rau muaj xim thiab ua rau tsaus nti.
(4) Cov teeb meem ua neej nyob. Cov kev ua neej tsis zoo xws li kev ntxhov siab, ib nrab ntawm dab noj hnub, pw tsis txaus yuav ua rau muaj melanin ntau ntxiv. Yog li, cov neeg muaj lub sijhawm pw tsaug zog tsis ruaj khov muaj cov tawv nqaij tsis ua haujlwm, uas yuav cuam tshuam rau cov khoom lag luam melanin tuaj.