The recent heat sent many of us reaching for the sunscreen. But now, some experts are warning this may not protect us against a potentially harmful sunray: infrared. Conventional sunscreens are designed to block out ultraviolet light - UVA and UVB - the rays that damage and burn the skin. However, these products do not block out infrared rays. These rays, which were discovered in 1800, transmit heat, raise skin temperature and are responsible for the warmth you feel when sitting in the sun. Infrared rays make up to half of the sun's energy (UVA and UVB combined make up between 5 per cent and 7 per cent) and one type in particular, infrared A, can penetrate the deepest layers of the skin - deeper than ultraviolet. Recent research in animals has suggested infrared A may play a role in skin cancer when combined with exposure to UVB. Infrared A may also contribute to ageing of the skin - scientists suggest it alters some of the biological processes involved in maintaining healthy skin cells, affecting the production of collagen, the protein that acts as scaffolding for the skin. This could ultimately result in wrinkles, sagging and ageing. The possible link between infrared A and cancer was first noted in the Eighties. However, more recent research at the University of Kiel in Germany found that mice exposed to UVB and infrared A rays together developed faster-growing skin cancer tumours than those exposed to UVB light alone, though those exposed to infrared A alone did not. Dr Nick Lowe, a consultant dermatologist at London's Cranley Clinic, says: 'There's no conclusive link between infrared A exposure and skin cancer as there is with UVA and UVB rays, but there is emerging evidence that they may be involved in some way when combined with UVB.' When it comes to skin ageing, the evidence is stronger, according to Professor Jean Krutmann of the Leibniz Research Institute for Environmental Medicine, in Dusseldorf, a world authority on infrared A. 'Infrared A damages the skin deep down by interfering with enzymes that maintain healthy skin renewal,' she says. 'This means more collagen is broken down than is replenished, resulting in premature ageing of the skin and loss of elasticity.' Professor Krutmann recently received a grant from the German Ministry of Science to use a new type of lamp that can mimic the amounts of UVA, UVB and infrared A found in natural sunlight to carry out further investigations in mice. Dr Lowe adds: 'We've known since the Seventies from research on animals that infrared rays, and heat in particular, produce changes in the skin, including increasing the size of blood vessels and permanently affecting the elasticity of tissues. Research suggests repetitive exposure may lead to development of thread veins and wrinkles more common in ageing skin.' Crucially, though sunscreen products usually contain protection against UVA and UVB, there is no ingredient that has been proven to offer the same barrier protection against infrared A. When suncreams were introduced in the Thirties, they only helped protect against UVB rays. It wasn't until the mid-Nineties that UVA rays were recognised as causing skin cancer, too, and filters were added to sunscreens. 'This may be what will happen with infrared A rays, too, but we just don't know yet,' says Dr Lowe. The one major drawback, he says, is that there is no chemical filter that has been proven to block the effects of infrared. 'However, some antioxidants, including vitamins C and E, and chemicals such as coenzyme Q10 may be able to help repair or mop up damage caused by infrared A. 'This is the subject of ongoing research. The main problem is that there's no regulation of ingredients or equivalent to the SPF system of ratings.' So, how can you protect yourself? Dr Lowe takes lycopene (an antioxidant found in tomatoes and red fruit) and co-enzyme Q10 supplements, and wears UVA/ UVB sun protection cream. 'Sun protection clothing is also effective, but often overlooked,' he says. While suncream companies include antioxidants in their creams, in Britain only a few brands offer specific protection against infrared A - these include Ladival and Eriis. Some British dermatologists say more research is needed before it can be said that specific protection against infrared A is needed. A spokesman for the British Association of Dermatologists said more evidence was needed on infrared A before it could consider changing its advice on effective sun protection. Fiona Osgun, health information officer at Cancer Research UK, says: 'There's no good evidence that infrared light causes skin cancer.' Dr Bav Shergill, a consultant dermatologist at Queen Victoria Hospital, East Grinstead, West Sussex, and a member of the British Association of Dermatologists' skin cancer committee, is cautious, too. He says infrared A does appear to be linked to 'a cascade of reactions within the skin', including breakdown of collagen, but adds: 'It's too early to say whether this is clinically relevant. I am open to infrared A having a cosmetic effect on the skin, though.'
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