News

05-12-2016

Australia has the highest rate of skin cancer int he world, two in every three Australians will be diagnosed with skin cancer by the age of 70 years. Since 1982 we have been advised to Slip, Slop, Slap, Slide and Seek.

To "slop",  there are two types of active ingredient in sunscreen.

The organic filters or "Chemical" sunscreens offer more coverage against UVA and UVB rays, but are more irritating to the skin potentially. The filters act by absorbing either the UVA,  UVB radiation or both. Bisoctrizole absorbs UV radiation and reflects  it. Recently there has been concern that some chemical sunscreens have hormonal effects in humans, these include oxybenzone, octyl methoxycinnamate, homosalate and 4--methyl-benzlidene camphor. This activity has been demonstrated at extremely high doses in animal and tissue testing. The dose is much higher than usual sunscreen application can achieve. These ingredients have been approved for use in sunscreens by the Food and Drug Administration in the US and by the European Union.

Chemical sunscreens can cause irritation and allergy, the most allergenic ingredients are butyl methoxydibenzoylmethane, oxybenzone and 4-methyl-benzylidene camphor ( 4MBC). The chemicals Tinosorb S and Tinosorb M provide UVB and UVA protection, rarely irritate skin and have no known endocrine effects to date.

The metal oxide sunscreens or "Physical" sunscreens are reflectors, providing a protective layer on the skin to reflect the UV rays. Due to their make-up, zinc oxide and titanium oxide produce a ghosting effect and many people dislike their look when using them.  Nanotechnology is used to make the minerals into smaller nanoparticles with the same UV protection, but the products are more aesthetically pleasing.

The Therapeutic Goods Administration ( TGA) released a statement this year after reviewing the safety of nanoparticles, announcing that "The potential for titanium dioxide and zinc oxide nanoparticles in sunscreens to cause adverse effects depends primarily on the ability of the nanoparticles to reach viable skin cells." To date, no research over many years has demonstrated nanoparticles penetrating beyond the surface skin layers.

The recommended sunscreen is SPF 30 or above, all sunscreens must be listed with the TGA and tested and rated. There are many different formulations available to find the one that suits you. The  amount of sunscreen advised to apply is one teaspoon of sunscreen per limb, one each for the front and back of the torso, one for the face, ears and neck. It should be applied at least 20 minutes before going outdoors and re-applied every 2 hours and after swimming or exercising. Those sunscreens with added insect repellent have been found to reduce the sunscreen effectiveness by up to a third.

The SunSmart UV alert is reported daily by the Bureau of Meteorology, and identifies times during the days when the UV level is 3 or above and sun protection is needed. There is an app for smartphones and The Alert is published in the weather section of newspapers.

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