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Nanosunscreens deemed safe


People concerned that tiny nanoparticles used in many sunscreens pose a health risk have been reassured that they are safe to use.

Nanoparticles such as zinc oxide and titanium oxide are included in many sunscreens to broaden the range of UV light they block, but there has been ongoing public debate about their safety.

However, researchers from the Royal Melbourne Institute of Technology  found that nanoparticles used in sunscreens do not increase levels of reactive oxygen – damaging free radicals – in human cells exposed to UVA light, and that the UV in sunlight itself represents a far bigger risk when it comes to skin damage and cancer.

The researchers found that in stressed skin exposed to harmful UV light, reactive oxygen species such as peroxide and superoxide increase dramatically, causing damage to cells and tissues. This type of damage has been implicated in both skin ageing and cancer, and is the target of antioxidant products.

Lead researcher Associate Professor Paul Wright and his team exposed human immune cells to both UVA light alone and to UVA combined with sunscreen nanoparticles to see if the particles increased the generation of reactive oxygen species.

They found that the UVA light itself caused a large increase in reactive oxygen species, and that the zinc oxide and titanium oxide did not lead to further increases.

Professor Wright said that excessive UV light is far more likely to damage the skin and cause cancer than nanoparticle sunscreens, and that people should use the most effective broad spectrum sunscreens as part of their sun protection strategy.

Kirsty Waterford