Cosmetic Surgery and Beauty Magazine #66

feature
The current weight
of evidence suggests
nanoparticles such
as titanium dioxide
or zinc dioxide pose
no risk to human
health
The case for
Scientists on the other side of the nanoparticle debate continue to maintain
sunscreen is essential in protecting the skin from UV damage and consider the
SPF rating the most effective indication of sunscreen quality.
An amalgamation of researchers from the German Center of Experimental
and Applied Cutaneous Physiology, various L’Oreal Research and Development
branches and the Department of Medicine at the University of Queensland
simply state there is insufficient evidence to support the idea that nanoparticles
in sunscreen are harmful to the skin and argue that most studies showing
nanoparticle penetration are not based on human skin.
‘Most available theoretical and experimental evidence suggests that insoluble
nanoparticles do not penetrate into or through normal or compromised human
skin,’ the report states. ‘Overall, the current weight of evidence suggests that
nanomaterials such as titanium dioxide or zinc oxide nanoparticles pose no risk
to human skin or human health.’
A study by Cross, Innes, Roberts, Tsuzuki, Robertson and McCormick at the
University of Queensland found less than 0.03% of the topically applied zinc
nanoparticles penetrate the epidermis, while an article published in the Journal
of Nanoparticle Research relentlessly addresses and refutes a smorgasbord of
claims by those parties against nanoparticles in sunscreen.
In tackling the claim that titanium dioxide is a possible carcinogen for humans,
Prof David Berube at North Carolina State University has a body of research
that shows both orally and topically applied titanium dioxide does not induce
any significant increase in tumour frequency. He also contests the notion
that skin-damaging free radical formation is ‘propelled’ by titanium dioxide
nanoparticles in sunscreens. While he concedes there is evidence to suggest
certain nanoparticles can induce free radical formation in the presence of light,
he claims this would only damage human DNA if the nanoparticles penetrated
live skin cells. He says the evidence overwhelmingly suggests this penetration
simply does not occur.
The European Commission Scientific Committee on Consumer Safety (SCCS)
study on nanoparticles of zinc oxide concluded: ‘In summary, it is concluded
on the basis of available evidence that the use of ZnO nanoparticles with the
characteristics as indicated below, at a concentration up to 25 percent as a UVfilter
in sunscreens, can be considered not to pose a risk of adverse effects in
humans after dermal application.’
Consensus is clearly a way off and, until a definitive answer has been found
as to the safety of nanoparticles, with no clear labelling currently demanded
it seems awareness is key. It is also important to note that a nanoparticle is
merely the diameter measurement of any particle (less than 100 nanometers).
It is important to specify the type of nanoparticle as the evidence against one
type of nanoparticle (eg titanium dioxide) may be totally different to the evidence
regarding another (eg zinc oxide).
In the short term, consumers will have to make up their own minds as to the
benefit versus risk of nanoparticles. Yet as the height of summer approaches,
sun protection – nanoparticles or no – should remain at the forefront of every
Australian’s consciousness. csbm
92 www.cosbeauty.com.au