30/06/2010
Suncream potentially toxic if eaten
Nanoparticles present in suncreams could prove toxic if accidently consumed orally, according to new 
research.
A study at the Department of Pharmacology and Toxicology at University of Utah has shown that direct nanoparticle to living cell contact causes cell death and that this direct contact with colon cells is achieved by a small oral consumption.
Leader of the study Philip Moos said: “There is ongoing concern about the potential toxicity of nanoparticles of various materials, which may have different physical and chemical properties than larger particles. Barely 1/50,000 the width of a human hair, nanoparticles are used in foods, cosmetics and other products.”
The team of six researchers compared the effect of conventional zinc oxide powder on a culture of colon cells to the effect of zinc oxide nanoparticles.
They found that the nanoparticles were twice as toxic to the colon cells than the larger particles.
Independent health consultant Helen Lynn said: “I’m not surprised by this study; I have been thinking for some time that more research should be done into nanoparticles. However, given that they may also pass through the skin I am concerned that the amount of zinc oxide inside the body could be more than this study estimates.”
The concentration of nanoparticles found to be toxic to the colon cells in the study was the equivalent of eating 2 grams of sunscreen, which could put children in danger.
Mr Moos said: “Unintended exposure to nano-sized zinc oxide from children accidently eating sunscreen products is a typical public concern, motivating the study of the effects of nanoparticles in the colon.”
The study, published in ACS’ Chemical Research in Toxicolgy, concluded that particle size affects the toxicity of zinc oxide, which is added to suncream to offer protection from UV rays.
The scientists will now experiment with zinc nanoparticles on laboratory animals and humans.