The Sunday Times 27 July 2014
Skin cancer is on the rise, as doubts increase about the efficacy of sunscreens. We report on the latest research
Lethal skin-cancer rates have quadrupled in a generation, as increasingly we don’t seem to be getting the best from our sunscreen. And this is a deadly serious matter: malignant melanoma causes more than 2,200 deaths a year in the UK, and it is the second most common form of cancer in the 15-34 age group. Current estimates indicate 1 in 50 of us will get malignant melanoma, and even if it doesn’t prove fatal, surgical removal of the tumours can cause permanent scars. Even more worrying is the fact that most skin-cancer victims claim that they used sunscreen regularly. So what does the science have to say on the matter, and what are the best products?
Consumer research has claimed that the SPF values declared on products often only have a passing connection with their real performance. In recent tests by the consumer organisation Which?, products by Piz Buin, Malibu and Hawaiian Tropic all failed to provide the UV protection they claimed on the bottle. Currently, sunscreens are tested by applying them thickly, like patches of lard, onto the skin of volunteers, who are then exposed to artificial sunlight. The burn time with and without the protection of the product is translated into the sun protection factor, or SPF. An SPF of 30 means that if unprotected skin burns in three minutes, it would take 90 minutes to burn with the protection.
However, much of this protection is a myth, because the manufacturers privately acknowledge that nobody in their right mind would slather on the large quantities that are used for testing, so in reality there is a wide variation in the levels of protection people get. And now it seems this variation might be much more serious than previously believed.
Research by a group of pharmaceutical chemists from the University of Nantes, in France, has shown that the anti-inflammatory ingredients routinely added to sunscreen as UV filters may dramatically skew SPF readings, because they can delay the rate at which the skin turns red when exposed to UV light, therefore allowing the product to be given a higher SPF. Meanwhile, the UV light may be doing serious damage to the skin. Some of these anti-inflammatory chemicals become more powerful in the sun and some become weaker. One of them, homosalate, which is related to aspirin, was remarkably effective in reducing skin reddening in tests, meaning users of products containing it could be blissfully unaware of the risks.
“The majority of sunscreens contain anti-inflammatory ingredients, and many don’t achieve the level of protection they claim,” says Laurence Coiffard, professor of industrial pharmacology at Nantes, who has published more than 30 studies on sunscreen efficacy. “The SPF test currently in use is based purely on whether a product prevents redness in the skin of volunteers. If it contains anti-inflammatory chemicals, it will prevent redness. Under the current system, it would even be possible to have a sunscreen with no UV filters that simply stopped redness.”
Last year, the French National Institute for Consumer Affairs checked 10 baby sunscreens using Coiffard’s method. Products produced by Clarins, Klorane, Mustela, Nivea Baby, Bioregena and Natessance did not reach the level of protection they claimed. Those that passed were Avène, Mixa Solaire, Vichy and Alga Maris. These products all contain dozens of ingredients, and it is impossible to prove or disprove what most of them do. However, it is reasonable to question whether anti-inflammatories will skew the results, and Coiffard’s research indicates they do. She has now turned her efforts to searching for better types of UV filter in compounds found in salt-loving coastal plants.
Screen test: these are the products we can trust
British experts think she may have a point with her argument about anti-inflammatories. John Hawk, emeritus professor of photodermatology at King’s College London, says more research is needed, but he added: “If a sunscreen contains anti-inflammatories, it reduces sunburn without necessarily protecting against DNA damage, which is potentially worrying.”
Sunscreen products are regulated and classed as over-the-counter medicines in America. Coiffard thinks such regulation should be extended to Europe, a prospect that would mean all products would have to undergo the rigorous testing for safety and efficacy that is applied to medicines — something that manufacturers would not necessarily welcome. All the companies that have been criticised in recent research have insisted their products do perform to the SPF standards claimed and adhere to European ingredient regulations. However, they are unwilling to list which products contain identified anti-inflammatories, but Dr Mike Bell, scientific skincare adviser to Boots, says Coiffard has suggested nothing more than an interesting hypothesis. “I do not believe there is any effect relevant to consumers,” he said.
For holidaymakers, Coiffard’s research and 30 published papers certainly sound plausible; however, unless you are prepared to go shopping armed with a checklist of complex chemical compounds, the best hope may be to stick to products that use traditional sunblocks, zinc oxide and titanium dioxide, that have not been modified to be absorbed by the skin.
“I think part of the problem is that these are relatively expensive ingredients, so the big manufacturers are looking for alternatives,” said Amanda McGillivray of the Natural Skincare Company. She sells a zinc oxide-based product called Caribbean Blue (£15) that is imported from St Lucia. BareMinerals SPF 30 Natural Sunscreen powder (£25) is based on mica and titanium dioxide, and is similarly free of manufactured chemicals, preservatives, fragrances or oils. It sits firmly on top of the skin without penetrating or rubbing off.
Dr Marko Lens, a London-based dermatologist, has just launched Zelens Daily Defence sunscreen SPF 30 (£55). It contains an enzyme called endonuclease, which aids DNA repair, and organic UV filters that sit in silica-based capsules that are not in direct contact with the skin. Lens points out that there are a number of sunscreen products on the market that openly flout regulations by claiming to be SPF 70, when the maximum permitted by EU labelling restrictions is 50+, and that certain “boil on the beach” formulas on the market would actually be damaged by exposure to the sun. “Some of them contain alcohol, which not only dries out the skin, but would also evaporate and alter the photostability of the product,” he says. “It’s ridiculous. Why aren’t Trading Standards doing something about this? People’s health is at risk.”
Meanwhile, other researchers in Marseilles have been investigating the possibility of measuring reduction in DNA damage as a means of assessing sunscreen efficacy. Once they get this right, CPC — or skin cancer protection codes — may replace SPF values. In the meantime, however, the argument about what works and what doesn’t is set to run and run.