Mark
Henderson, Science Correspondent
The
Sunday Times (London)
The main chemical used in sun lotions to
filter out ultraviolet light may be TOXIC, particularly when exposed
to sunshine.
Octyl methoxycinnamate (OMC), which is present in 90 per cent of
sunscreen brands, was found to kill mouse cells even at low doses
in a study by Norwegian scientists.
It is not certain that the effects on mice are repeated in human
beings, although the findings reported in New Scientist magazine
suggest that human cells could be damaged if a sunscreen containing
OMC penetrates the outer layer of dead skin and comes into contact
with living tissue.
Terje Christensen, a biophysicist from the Norwegian Radiation
Protection Authority, near Oslo, said her research showed that sunscreens
should be treated with caution, and used only when it was impractical
to stay indoors or to shield the skin from the sun with clothes.
The chemical is used as a filter for the more harmful UVB light.
In Dr Christensen's study, mouse tissue grown in culture was treated
with a solution of OMC at five parts per million - a much lower
concentration than in sunscreens. Half the cells treated with OMC
died, compared with fewer than 10 per cent in a control experiment.
When researchers shone a lamp for two hours to simulate midday sunshine,
more cells died. Dr Christensen suggested that the reaction between
OMC and sunlight created an effect that was twice as toxic as the
chemical alone.
The Cosmetic Toiletry and Perfumery Association, which represents
sunscreen manufacturers in Britain, said that OMC "has been
thoroughly tested for safety" and was approved by regulatory
authorities in Europe and the US.