Nhang dieu can biet ve kem chdng nang
>fr DS. HUYNH VAN NHIEM
K
em ch6^ng n^ng can thiet de bao ve lan da chong lai nhiJng tkc hai cua^nh sdng mdt trcri.
Trong anh sdng mat trdi co nhi^u loai tia vdi do dai song (biffic song) khac nhau, dang chii y nhat la cdc tia ciJc tim (con goi la tia til ngoai hay UV), mdt thUcmg khflng nhm thay, co tac dung giup da tong hop vitamin D, nhUng vdi mile d6 cao, tia UV Id tdc nhan gay b6ng da, sam da, nhdn da, n6i tan nhang... vd cd ung thif da. Anh sang nhin thay dcroc co do ddi song tren 400nra vd kh6ng gay hai cho da,
Cdc tia UV gay hai nhd't c6 do ddi s6ng til 290nm den 400nm, dUdc chia thdnh 2 mile: Tia UVB c6 d0 ddi s6ng giffa 290 - 320nm, tia UVA c6 dg ddi s6ng til 320 - 400nm.
BiJc xa ciia tia UVB chieu len mdt dd't chi chiem chUa den 57t trong tdt ca cdc bile xa tia UV, nhimg d6 Iai Id nguydn nhdn chinh gdy chdy ndng, bflng da vd ung thir da. Tia UVB c6 cubng dg manh nhat vdo miJa Xudn va miia He, trong ngdy tCr 10 gi6 sdng den 4 gi6 chi4u, hodc d vung c6 cao d§ ldn, vd co the phdn xa manh tren be mdt ciia bdi cdt, nu'dc, tuyet, bdng, kinh,.,
Ta thff&ng tiep xuc nhieu hem vdi tia UVA vi nd xuyen dUdc qua cdc ddm mdy. khi trdi ram va qua cd cufa kinh. Tia UVA phd huy Idp collagen vd elastin sau du'di da, gay ldo hda da, ndm da, nhdn da, dong thdi gdp phdn gdy dpt bien DNA vd ung thff da.
Rifing tia UVC c6 dg ddi sdng ngin htm 290nm, nguy hiem nhat, nhffng rdt may !d tang 6-z6n hd'p
Kem chdng nSng giiip da tranh dugc nhdng tkc hai cua anh nkng mSt trdi thu gdn nhl/ hoan toan, nen it khi tia UVC den be mdt trdi dat.
Car l.».u kvm rhduan^uiii Co nhieu dang kem chong ndng:
kem, nudc, dung dich de phun (xit),, cd tac dung loc hoSc ngan can dnh ndng anh hffdng len da, vdi thdnh phan hoat cha't td hoa chat tong hop hoac chd't khodng.
Do bao v^ dffoc ghi bdng chi so SPF hodc PA. '
- SPF (Sun Protection Factor):
bieu thi khoang thdi gian de mot Ioai kem cho'ng ndng bao ve fan da khdi bi do len dffdi tac dung cua dnh sdng mat trdi so vdi thdi gian khong dffoc bdo ve. Vi du, neu khong dffcfc bdo ve da cua ban bdt dau dd len sau 10 phiit dudi anh mdt trdi, thi khi bdi kem c6 SPF 15, phai lien tuc phoi ndng 150 phiit thi ldn da ciia ban mdi bdt dau chuyen sang mdu dd.
Bg bao v^ cdng ldn, hi^u qua chong ndng cdng cao. Loai SPF 15
Loai tin D^ dAIsdng
UVC
< 290nm UV8 290 - 320nm
UVA 320 - 400nm
Anh sang thay dUOi:
> 400nm
bdo ve da khdi 93% tia ndng mdt trdi, con SPF 30, cd dg bdo v$ I6n den 979!:. Tren thffc td, khdng can diing loai SPF vuot qud 50.
- PA (Protection Factor of UVA) ddnh dd'u tir PA+ de'n PA+++, cd tac dung chong tia UVA tff 4 den 12 gid.
Nhffng kem chong ndng cd dp bao ve SPF tff 15 trd len, hodc cd ghi Broad spectrum. Full spectrum (Phd bdo ve rong), hodc SPF vdl 2 cha sd (vi du SPF 60 A=B, SPF 60-12 ..) cd the ngdn ca tia UVA va UVB, mdi cd hieu qua bao v§
tdt cho da, ke ca ngffa ung thff da.
Khi sff dung kem chd'ng ndng, ban nen boi mpt ldp khd ddy, 15 - 20 phut trffdc khi ra ndng vd ldp Iai khoang 2 gid mpt ldn, Vdi loai binh xit, thi phdi phun nhieu ldp vd chd xdt de kem dfftfc trdi d4u.
Nhffng loai kem cd ghi nhilTng ehff Wa(crproo/; Sweatproof. Water-VS' THu6c;^^UCKHQfc.'.d5U4il3.7.20l4l
^resistant, Sweat-resistant (Khong bi dnh hudng cua nudc hoac mo hdi) thdt sff tdc dung cung chi han che trong thdi gian ngan, cho nen muon CO hi^u qua, ban phai bdi lai kem chong nang sau m6i lan tam, hodc sau khi lau m6 hdi.
Hang ngay, khi ra nang, td^t nhat la c ^ trang bi ndn, kinh ram can tia UV, cung vdi trang phuc bang vai day, due... hcfn la chi dffa vao kem chong nang.
Kem chd'ng n d n g CO g a y n g u y h i e m ?
Cac loai kem chd'ng nang cd chila khoang chd't d l ngan tia sang mat trdi nhff oxid kem hode dioxid titan, cd tdc dung bao ve tdt, it gdy kich uiig, nhimg khi bdi len da se de lai mdt ldp mau trang bac tr^n da. De khac phue nhffcfc diem nay, g^n ddy, nhieu nhd san xudt kem chd'ng nang bang nhiftig hat kim loai nano (cd kich thffdc nanomet), khdng mdu. Nhffng cd y kid'n quan ngai nhiing vi hat kim loai nay se th^m thd'u qua da, vao mdu vd gan, CO the gay nguy hiem. Cho den nay, dilu nay van chffa dffpc cac co quan CO tham quyen xae nhdn.
Mot so' kem cho'ng nang cd chffa hda chat lpc tia cffc tim nhff avobemon (Parsol 1789), oxybenzon, benzophenon, hodc octylcrylen, co the gdy kich tifng cho da vd niem mac, tranh d^ eham vao mat va khdng n§n dung cho tre em.
Mot so'kem chong nang cd chffa chdt retinyl palmitat - mpt dan xuat cua vitamin A - giup chd'ng lao hoa da. Vdi liiu cao, chat ndy cd t i l m nang gay ung thff tren dong vdt thi nghiem, nhffng vdi lieu binh thffdng trong kem chd'ng nang thi khdng nguy hiem; chi can han ch§' sff dung cho tre em va phu nff mang thai.
Mpt so' ngffdi co the bi di iing vdi mpt so' thanh phan ciia kem chd'ng ndng hodc noi mun khi bdi kem nay, cho nen can Iffa chpn va thff trffdc de chpn loai kem phu hpp.
Ldu y: Khong dung binh xit trffc tiep len mat, ma ehi xit nd trong ban tay roi cha xdt len mat, d l cdc chd't trong kem cho'ng ndng khong gdy hai cho dffdng thd hay niem mac mieng, mat . ^
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Duoig chef
L
ong Iffn, tiet canh trffdc nay ludn la mdn khoai khau cua cac de tff Iffu linh. Theo thdi gian, mdn nay ngdy cang dffdc bien tau tff Ign cho de'n cac loai gia sue, gia cam khac nhff gd, vit, thd, d§, ngan, ngdng, k l ca... ran. Ngay nay, vdi ddn nhau, tie't canh cua bat ky loai dpng vat nao len ban nhau cung deu dffcfc "thdng qua", vd tuy theo dd quy hilm cua con vdt do ndi ldn tinh chiu ehdi va dang cap trong ban nhau, ba't cha'p nhiJng thdng tin vl dich cum gia cdm dang lan rong hodc nhiJng trffdng hdp bdnh cd'p cffu do nhiem trung huye't dang sd ma nguydn nhdn chinh la bat tiet canh.Ngffdi ta thich an tie't canh.
Trffdc het, phai khang dinh la dd'i vdi nhieu ngffdi, dac bidt la dan nhdu, tiet canh va long (ndi tang ddng vat, trff ccf bdp va xffpng) ludn Id mdn ngon khd chd'i tff, dung kem vdi rffpu thi dung Id "trSn ca tuyet vdi", Mdn an nay ngon ngay tff cai nhin dau tidn: bat tiet dd tffffi sdng sanh nhff mdi Idy ra khdi
eon vdt so'ng, tren mat rac d^u d|
phdng rang, kfem vai la rau hiiii qud* xanh tffcfi va vai miing gai thit nac lan ldn. Khi an, cac bdr nhd ta cam nhan mpt vi bdo nga;
cua tie't va dau phong, cdng vd mieng dai, gidn san sat cua sui va thit nac, kem vi cay n6ng cu(
hdp rffpu ndn qu§n het sff ddi vaJ qudn ludn nhffng h i l m nguy danii rinh rap. Cting phdi ke de'n mSl quan diem p h i bid'n theo kieu "at gi bo na'y": dn dc {heo, bd...) thi thdng minh (!}, an tim b l tim, as thdn bo than, an tie't b l mdu.. ds giup cde qudn ban mdn tilt canli dn nen lam ra.
Mdn an nay tuy ed "ngon" nhiflifl chffa ehae da "lanh". Thdt v^yi
THUOC & s a c KHOE so'504 (15.7.2014)
