Nanoparticle sunscreens OK, says ASMI
The Australian Self-Medication Industry (ASMI) has said that concerns being expressed by Friends of the Earth about nanoparticles in some sunscreens aren’t supported by the weight of scientific evidence.
Nano zinc oxide and titanium dioxide have been used in sunscreens for more than a decade, says ASMI executive director Dr Deon Schoombie – and research to date hasn’t demonstrated a link between the nano-sized ingredients in some sunscreens and serious health problems.
ASMI says some comments on the subject seemed to misrepresent findings of research by Professor Brian Gulson, from Macquarie University’s Graduate School of the Environment, by implying that zinc found in blood and urine was proof that zinc oxide, when formulated as nanoparticles, penetrated the skin and could cause harm.
It says Professor Gulson led the research using two sunscreens, one made with nanoparticle zinc oxide and one with larger particles called micronized zinc oxide. Both were labelled with a ‘traceable’ isotope of zinc oxide.
Although Professor Gulson found that a small quantity of the ‘traceable’ zinc was absorbed through the skin and detected in the blood, this happened with subjects treated with nano zinc oxide and micronized zinc oxide, and he concluded that the quantity wasn’t significant and would cause no harm.
When discussing this research in 2010, he clearly stated that his methodology didn’t allow him to determine whether the traceable zinc in the blood was due to nano zinc oxide, or from zinc penetrating the skin as ‘dissolved’ zinc molecules, which are very much smaller than nano particles. He added that he would continue to use sunscreen containing zinc oxide on his grandchildren.
Australia’s Therapeutic Goods Administration (TGA) reviewed the use of nanoparticles in sunscreen in 2009. It found the evidence to date indicates that these nano-sized particles stay on the skin’s outer surface.
There was also no evidence of toxicity to sunscreen users, ASMI points out, despite the known use of zinc oxide in nanoparticle form in sunscreens since 1999.
TGA didn’t identify a requirement for specific safety warnings regarding nanoparticles of zinc oxide and titanium dioxide in sunscreen medicines, and concluded that there was no evidence to date to suggest that the safety profile of sunscreen containing nanoparticles was any different to sunscreen with larger particles.
ASMI’s Dr Schoombie says Australia has one of the highest rates of skin cancer in the world, and using sunscreen remains an important way to reduce the risk of developing skin cancer and premature skin ageing.
‘All sunscreens marketed in Australia are safe when used as directed and should be incorporated as part of a range of sun protection measures to avoid excess sun exposure,’ he says.
‘These include wearing long-sleeved clothing, avoiding sun exposure during the hottest part of the day, staying in the shade and wearing a hat and sunglasses.’