Tuesday, August 3, 1999 Published at 22:24 GMT 23:24 UK
Sunscreen 'increases cancer risk'
Wearing sunscreen could increase your cancer risk, say scientists
Wearing sunscreen makes people stay in the sun too long - and could release cancer-causing substances into the body, according to specialists.
And a British biochemist has suggested that the cocktail of chemicals involved in sunscreens could be converted into "free radical" molecules, which could cause cell damage and lead to cancer.
The US study, revealed on the BBC's Newsnight programme, appears to demonstrate why incidence of skin cancer has increased, even though sunscreens have become popular among fair-skinned people.
A spokesman said: "Don't stop using sunscreens but do remember that you shouldn't use them so you can sunbathe longer."
He found children using sunscreen returned from holiday with more skin moles - a possible sign of increased cancer risk.
He set out to see if this was because sunscreens were making sunbathers overconfident.
He said: "Consumers should be warned that using a sunscreen may increase the amount of time spent in the sun.
"Because of that it may increase your risk of sun cancer."
Meanwhile, Dr John Knowland, a biochemist at Oxford University, is looking at another reason why sunscreen may be behind increased skin cancer rates.
He said: "The important thing to remember is that a sunscreen that absorbs energy cannot actually destroy that energy, it has to do something with it.
"The concern that some people have is that they can convert the light energy into chemical energy, which is potentially damaging."
He and his colleagues are trying to model the effects of sunlight on human skin, looking at how the DNA might be changed.
Professor Jack Cuzick, head of the epidemiology unit at the Imperial Cancer Research Fund, said: "Obviously people would be more at risk if they didn't wear any sunscreen but they should not rely solely on sunscreen to protect themselves against the sun.
"If they do use a sunscreen they should make sure it has both UVA and UVB protection.
"This research does not change our advice that the best way to protect against skin cancer is to cover up and moderate your exposure to the sun."