Yintoni i-vitamin D?
Yivithamini enyibilikayo emafutheni eveliswa ikakhulu lusu xa ivezwa kwimitha ye-ultraviolet B (UVB). Idlala indima ebalulekileyo kwimpilo yamathambo, inkqubo yomzimba yokuzikhusela kunye ne-calcium metabolism.
Ulwalamano phakathi kwemitha ye-UV kunye ne-vitamin D
Imitha ye-UVB yeyona nto iphambili ekuvelisweni kwe-vitamin D.
Xa ulusu luvezwe kwi-UVB, lunokuvelisa i-vitamin D3 (cholecalciferol) ngokusebenzisa izinto ezibangela i-cholesterol.
1. Imitha ye-UVB ibangela ukwenziwa kweVitamin D
Ulusu lune-cholesterol evela kwi-cholesterol ebizwa ngokuba yi-7-dehydrocholesterol.
Xa ujongene nemitha ye-UVB (ubude begagasi 290–315 nm), le khompawundi iguqulwa ibe yi-previtamin D₃, ethi emva koko itshintshe ibe yi-vitamin D ngobushushu₃(i-cholecalciferol).
IVithamin D₃ithuthwa iye esibindini nasezintsoni, apho iguqulwa ibe yimo yayo esebenzayo, i-calcitriol (1,25-dihydroxyvitamin D).
2. Izinto ezichaphazela ukuveliswa kweVithamin D
Umbala wolusu: Ulusu olumnyama (i-melanin ephezulu) lunciphisa ukufunxwa kwe-UVB, nto leyo edinga ixesha elide lokukhanya kwelanga.
Ububanzi kunye nexesha lonyaka: Ubungakanani be-UVB buphantsi ebusika nakwiindawo eziphezulu, nto leyo enciphisa ukwenziwa kwe-vitamin D.
Ixesha lemini: Emini ngelanga (10 AM)–3 PM) inika ukukhanya okunamandla kakhulu kwe-UVB.
Ubudala: Abantu abadala bavelisa i-vitamin D encinci ngenxa yolusu oluncinci.
Ukusetyenziswa kwe-sunscreen: I-SPF engaphezu kwama-30 inokuthintela i-95% ye-UVB, nto leyo enciphisa ukwenziwa kwe-vitamin D.
3. Iingenelo zeVithamin D
Impilo yamathambo: Ikhuthaza ukufunxwa kwekhalsiyam, ithintela i-rickets (ebantwaneni) kunye ne-osteomalacia (kubantu abadala).
umsebenzi we-mmune: Uxhasa ulawulo lomzimba kwaye unokunciphisa iingozi zosulelo.
Ukulawulwa kweemvakalelo: Kunxulunyaniswa nokuveliswa kwe-serotonin, okunokuphucula impilo yengqondo.
4. Iingozi Zokuchatshazelwa Yi-UV Egqithisileyo
Ukonakala kwesikhumba: Imitha ye-UV ibangela ukutsha lilanga, ukwaluphala ngaphambi kwexesha, kunye notshintsho lwe-DNA.
Umhlaza wolusu: Ukuvezwa yi-UV ixesha elide kwandisa umngcipheko we-melanoma kunye nomhlaza wolusu ongengowe-melanoma.
Ubuthi beVithamin D: I-vitamin D egqithisileyo (edla ngokuvela kwizongezo, kungekhona elangeni) inokukhokelela kwi-hypercalcemia.
5. Ukulinganisela Ukukhanya Elangeni Nokhuseleko
Ukuvezwa okufutshane, rhoqo: 10–Imizuzu engama-30 yelanga emini (iingalo/imilenze ivuliwe, akukho sunscreen) 2–Izihlandlo ezi-3 ngeveki zidla ngokwanela ukwenza i-vitamin D (iyahluka ngohlobo lolusu kunye nendawo olukuyo).
Imithombo yokutya: Intlanzi enamafutha (isalmon, i-mackerel), ubisi oluqinisiweyo, kunye nezongezo zinceda ukugcina amanqanaba.
Ukhuseleko: Sebenzisa i-sunscreen emva kokuba sele uyichazile okokuqala ukuze uthintele umonakalo eluswini.
Ngaba oomatshini bokushushuluza isikhumba banalo olu sebenzi?
Uninzi lweemashini zorhwebo zokutshisa i-tan zisebenzisa i-UVA kune-UVB. I-UVA ingena nzulu, kodwa ayinandima ingako ekuvelisweni kwe-vitamin D.
Izifundo zifumanise ukuba, nokuba kukho i-UVB encinci, idosi iphezulu kakhulu kuneyo ifunyanwa lilanga lendalo kwaye ingozi enokubakho kulusu inkulu.
Ezinye iindlela ezikhuselekileyo:
Ukuchatshazelwa lilanga: Ukuchatshazelwa lilanga yimizuzu eli-10–15 ebusweni nasezingalweni yonke imihla.
Ukutya: intlanzi, amaqanda kunye nobisi oluqinisiweyo.
Izongezo: Izongezo zeVithamin D3 kufuneka zithathwe phantsi kweliso likagqirha.