Sun dan­ger over­rides vi­ta­min need

The Weekend Australian - Travel - - Health -

LY­ING in the sun with­out sun­screen in or­der to in­crease vi­ta­min D lev­els nec­es­sary for healthy bones is need­less and in­creases the dan­ger of skin can­cer, ac­cord­ing to new guide­lines is­sued to com­bat pub­lic con­fu­sion over how to bal­ance the risks.

The re­vised guide­lines on how much sun is re­quired to en­sure ad­e­quate vi­ta­min D — which is made in the skin on ex­po­sure to UVB rays in sun­light — give rec­om­mended sun ex­po­sure lim­its for each cap­i­tal in sum­mer and win­ter, and em­pha­sise that sun pro­tec­tion is re­quired when the UV in­dex is 3 or higher.

In sum­mer, most Aus­tralians will get all the sun they need by a few min­utes of nor­mal daily ac­tiv­i­ties, such as walk­ing to the shops in the morn­ing and af­ter­noon when the sun is less in­tense, and that de­lib­er­ate sun ex­po­sure is there­fore un­nec­es­sary.

In win­ter, how­ever, res­i­dents of south­ern states — Vic­to­ria, Tas­ma­nia and South Aus­tralia — don’t need to use sun pro­tec­tion for up to two to three hour stretches, be­cause the UVB rays are not strong enough.

In th­ese cases, peo­ple can en­sure ad­e­quate lev­els of vi­ta­min D— which is made when the skin is ex­posed to sun­light — by spend­ing two to three hours with their face, hands and arms ex­posed to the sun over the course of a week.

Sun pro­tec­tion is still nec­es­sary all year round in the North­ern Ter­ri­tory, Queens­land and parts of West­ern Aus­tralia, where UV lev­els re­main high enough to dam­age skin through win­ter.

More spe­cific ad­vice ap­plies to peo­ple who are ei­ther at higher risk of vi­ta­min D de­fi­ciency — such as dark-skinned peo­ple, Mus­lim women or oth­ers who cover their skin, the el­derly and ba­bies of vi­ta­min D de­fi­cient moth­ers — and those at higher risk of skin can­cer, such as peo­ple who have had skin can­cer be­fore. Th­ese peo­ple should ask their doc­tor whether they need vi­ta­min D sup­ple­ments.

Vi­ta­min D is start­ing to be cred­ited with a larger role in good health than pre­vi­ously thought. Stud­ies pub­lished re­cently have sug­gested it may cut the risk of breast, ovar­ian, colon and other can­cers by up to 50 per cent, al­though too high a dose can also cause the body to ab­sorb too much cal­cium and dam­age liver and kid­neys.

The new guide­lines, en­dorsed by the Can­cer Coun­cil Aus­tralia, Os­teo­poro­sis Aus­tralia, the Aus­tralasian Col­lege of Der­ma­tol­o­gists and the Aus­tralian and New Zealand Bone and Min­eral So­ci­ety, were launched in Melbourne yes­ter­day.

Can­cer Coun­cil CEO Ian Olver said the ‘‘ wrong peo­ple’’ were con­cerned about vi­ta­min D de­fi­ciency and re­search showed 17 per cent of teenagers and 13 per cent of adults mis­tak­enly thought they needed to spend time in the sun with­out sun­screen in or­der to boost vi­ta­min D lev­els.

‘‘ We’re alarmed that a small but sig­nif­i­cant num­ber of Aus­tralians are de­lib­er­ately seek­ing sun ex­po­sure with­out sun pro­tec­tion be­cause they’re con­cerned about vi­ta­min D, and are there­fore more likely to be putting them­selves at risk of skin can­cer,’’ Pro­fes­sor Olver said.

‘‘ The re­al­ity is that too many Aus­tralians get too much sun in sum­mer and in­crease their risk of can­cer, while some peo­ple don’t get enough sun, par­tic­u­larly in win­ter, and risk vi­ta­min D de­fi­ciency with pos­si­ble se­ri­ous health con­se­quences.’’

Pro­fes­sor Peter Ebel­ing, med­i­cal di­rec­tor of Os­teo­poro­sis Aus­tralia, said any­one who thought they were vi­ta­min D de­fi­cient ‘‘ should seek med­i­cal ad­vice, not seek more sun’’.

The new guide­lines also say there is ‘‘ emerg­ing ev­i­dence’’ that the op­ti­mum level of vi­ta­min D to main­tain healthy bones may be 50 per cent higher than the cur­rent rec­om­mended level — 75 nanomoles per litre, in­stead of the cur­rent 50 nmol/L. ‘‘ For the Aus­tralian pop­u­la­tion to achieve this [higher] level with­out putting them­selves at greater risk of skin can­cer through in­creased sun ex­po­sure, there would have to be an in­creased re­quire­ment for di­etary sources of vi­ta­min D,’’ the guide­lines say.

‘‘ Given foods with nat­u­rally oc­cur­ring vi­ta­min D cur­rently con­trib­ute very lit­tle to daily in­take for Aus­tralians, the for­ti­fi­ca­tion of core foods should be con­sid­ered.’’

Soak­ing it up: To main­tain vi­ta­min D lev­els, get some sun on about 15 per cent of the body – in­clud­ing face, arms and hands, for the rec­om­mended time

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