Sun – The Great Cover Up
Panicked into avoiding sunlight by the experts, we are now at unprecedented risk of diseases linked to deficiencies of vitamin D, including cancers, diabetes, multiple sclerosis, depression and high blood pressure. The time has come to let the sunshine in, says Pat Thomas
Slip. Slap. Slop. We all know the drill. Avoid the dangers of sun exposure by slipping into the shade, slapping on a hat and slopping on the sun cream. Only by following this advice can we avoid setting off the ‘skin cancer time bomb’ that threatens to blow up in our faces and destroy the health of the nation.
Conventional thinking says that exposure to UV radiation from the sun is the sole cause of skin cancer. The higher the number of sunshine hours you accumulate in your lifetime, the greater your risk. If you stay in the sun until you burn, especially in childhood, your risk also is greater. In response to this thinking, the UK government has spent more than £3m over the last decade on public health programmes, such as the current SunSmart campaign, that advise sun avoidance. At first glance many of the specifics of SunSmart seem sensible enough. For example:
- stay in the shade between 11am and 3pm;
- make sure you never burn;
- when out in the sun, cover up with a t-shirt, wide-brimmed hat and sunglasses;
- use factor 15-plus sunscreen.
But whatever the good intentions, it is advice that first and foremost takes no account of where we live – in a cloudy northerly country where sun is scarce. Worse, during the last decade masses of data have accumulated confirming that on balance the health risks of avoiding the sun are much more serious than the consequences of exposing ourselves to it. Yet public health advice has never been amended to take these data into account.
SunSmart is lowest common denominator advice doled out to everyone, but appropriate for only the fairest skinned individuals in the UK. We have nevertheless taken it to heart. While a few hard-core sun worshippers remain committed to pursuing the perfect tan, most people have cut down on their sun exposure, and as a nation we are buying more sunscreen each year.
Few parents now allow their children outside without copious and multifaceted sun protection, and media scare stories ensure that this is so. In 2003 Dr Rachael Morris-Jones, a dermatologist at St Thomas’s Hospital, London (and consultant to sun-cream manufacturer Vichy Laboratoires), claimed in The Daily Telegraph that parents who consistently fail to protect their children against sunburn should be prosecuted for ‘physical neglect’.
In some highly publicised cases they have been. In June 2002 Eve Hibbits, a mother from Ohio, was arrested, jailed and charged with three counts of ‘child endangerment’ after her children got badly burned during a visit to a fairground. She spent eight days in jail before the charges were dropped. In May last year a New Jersey man was charged with child abuse when his mentally disabled 12-year-old son was burned during a day at the beach. The indictment contended that he ‘failed to apply enough sunscreen’.
Such is the culture of fear surrounding the sun that proponents of sun exposure are hard to find, especially in dermatology. Nevertheless, there are dissenters who are willing to stick their necks out. Far from being a loony fringe, many are eminent and widely published scientists and academics.
In 1999, Dr Andrew Ness and his colleagues at the University of Bristol suggested in the British Medical Journal (BMJ) that the risks of sun exposure and the benefits of sun avoidance were vastly overstated. They noted that ‘the exact nature of the association between malignant melanoma (see the box ‘The epidemic that isn’t’, over the page) and exposure to sunlight has yet to be determined’ and that ‘even if reducing exposure to sunlight reduced the incidence of melanoma, its effect on overall mortality will be slight… Even the most forceful campaign could be expected to prevent only a few of these deaths’.
The editors of the BMJ went so far as to issue a statement to the press suggesting that regular sun exposure should be considered healthy. It sparked a furious debate in the medical and lay press in which Ness and his team were accused of undermining public health policies and misleading the public. Ironically, 1999 was also the year that the BMJ recorded the first ever case of vitamin-D deficiency in a white infant resulting from the use of high-potency sun cream.
Two years later, when the same authors revisited the topic and suggested that poverty, not sun protection, should receive priority in the government’s public health policies, they were vilified again.
Last year Dr Michael Holick, professor of dermatology at Boston University and author of more than 200 important papers on the subject of vitamin D and health, was forced to resign after publishing his book The UV Advantage, which advised five to 10 minutes a day of deliberate, unprotected sun exposure in order to stimulate adequate vitamin-D production in the skin. Holick’s employers described the ideas expressed in the book as ‘an embarrassment for this institution and an embarrassment for him’. Holick says: ‘[I was] punished for challenging one of the dogmas of dermatology… It’s almost like a religion in the sense that you’re either a believer or you’re not. If your thinking isn’t in line with establishment thinking, they don’t just get upset; they stop thinking clearly. It was the “without sun-block” bit that they didn’t like. Apparently, it’s forbidden to tell people to go out without sun-block.’
Among the most outspoken dissenters, though, is Dr A Bernard Ackerman, founder of the Ackerman Academy of Dermatopathology in New York. A distinguished dermatologist and one of the world’s foremost authorities on skin cancer, Ackerman is adamant that dermatology’s current view of skin cancer is simply ‘replete with nonsense’. He contends that advice to avoid the sun is based on bad science and a dogmatic belief that the sun is the sole cause of skin cancer.
The prevailing belief is that as the body absorbs UV rays, there is a decreased immune response. On the one hand, this reaction is healthy because it prevents excessive swelling and damage to the skin as a result of sun exposure. But in some cases sun exposure may trigger immunosuppression to such a degree that it prevents the immune system from recognising and destroying any potential malignancies. This is not by any means certain, however. The degree of sensitivity to UV radiation varies widely among individuals, and why some of us should be more affected by sun exposure than others is considered a mystery.
In a recent interview with The New York Times, Ackerman said: ‘Taken as a whole, the research [linking sun exposure to melanoma] is inconsistent and fails to make the case.’ He noted research showing that the most common sites for melanoma among white people – the back of legs and arms in women, and the back in men – are places that accumulate the least amount of sun over a lifetime. In black and Asian people, the most common sites for melanoma are the soles of the feet and the palms of the hands: again, areas that are not regularly exposed to the sun.
He also cited studies showing that increased sunlight exposure paradoxically reduces the risk of both developing melanoma and dying from it. For instance, writing in the Journal of Investigative Dermatology in 2003, Dutch scientists reported that they had found that a lifetime of sun exposure was predominantly linked to a higher incidence of squamous-cell carcinoma (see the box ‘The epidemic that isn’t’, right). As expected, sunburn before the age of 20 was associated with an increased risk of malignant melanoma and other non-malignant skin cancers. What wasn’t expected was that while those with the highest cumulative sun exposure over their lifetimes had more moles and warts, they also had a lower risk of malignant melanoma. These results confirmed those of earlier investigations showing that adults who work and children who play outdoors and are regularly exposed to sun are less likely to develop melanoma than those who work or play indoors. The key, it seems is regular moderate exposure, rather than irregular intense exposure that produces burning.
In truth, the factors that can contribute to an individual’s risk of melanoma are diverse. Sitting in the sun until you burn is one accepted factor, but lifestyle is also highly influential.
Smoking, for example, can triple your risk of developing skin cancer. Tobacco smoke contains several carcinogenic and co-carcinogenic compounds that can promote skin cancer, including nitrosamines, polycyclic aromatic hydrocarbons, aromatic amines, unsaturated aldehydes and phenolics. These chemicals also suppress immune functions, which are necessary to combat sun damage. Arsenic-containing pesticides have the same effect.
Exposure to prescription drugs is also a factor. Antibiotics such as tetracyclines and sulfonamides, and drugs such as thiazide diuretics, chlorpromazine, oral contraceptives and anti-depressants can raise the risk of skin cancer by increasing the skin’s sensitivity to UV light, making it more susceptible to sun damage. Alcohol – a common component of the sunshine holiday – can also make skin more UV-sensitive.
According to the US National Academy of Sciences, the development of skin cancer is also associated with poor dietary habits. For three decades scientifi c studies have linked the over-consumption of polyunsaturated fats, from sunfl ower, saffl ower and other vegetable oils with the increase in malignant melanoma worldwide. Once consumed, these oils work their way to the skin surface, where they are oxidised by sunlight to create free radicals – unstable molecules that damage skin-cell DNA.
In 1987 Australian researchers showed that melanoma patients’ skin contained much higher levels of omegasix polyunsaturated fatty acids than that of healthy individuals. And it’s not just people in sunny climates that are at risk. Ten years later, a study of more than 50,000 Norwegians with malignant melanoma also found that high consumption of polyunsaturated oils significantly increased the risk of melanoma, especially in women.
Rather than think about these variables most of us just follow the SunSmart advice to stay out of the sun and cover up with sun-cream; but this, too, is problematical. For instance, while sunscreen use may reduce the risk of squamous-cell carcinoma, its effect on basal-cell carcinoma (see the box ‘The epidemic that isn’t’, right) and potentially deadly malignant melanoma is much less clear. Recent studies indicate a higher rate of melanoma among men who regularly use sunscreens and a higher rate of basal cell carcinoma among women using sunscreens. The accumulated evidence is now so strong that a June 2004 editorial in the prestigious journal Archives of Dermatology concluded that there was simply no evidence to support the idea that sun creams were effective protection against melanoma. What sunscreens can do, however, is drastically lower production of vitamin D in the skin, and this may be their most damaging consequence.
Up to 90 per cent of the body’s supply of vitamin D is made in the skin as a result of sun exposure. Available scientific evidence suggests that a sun-protection factor (SPF) eight sunscreen prevents 95 per cent of vitamin-D production in the skin. With an SPF 30 sun cream, there is 99-100 per cent blockage.
Dr Ann Webb, reader at the School of Earth Atmospheric and Environmental Sciences at the University of Manchester, believes that SunSmart advice may have a ‘significant negative impact on vitamin D production’. Working with experts at the Norwegian Institute for Air Research, a team led by Webb recently produced important data showing that 10 to 15 minutes of unprotected sun exposure at noon, exposing around a quarter of your total skin surface area (that is, wearing a T-shirt and shorts), is necessary for the average light-skinned person in the UK to ensure adequate vitamin-D production. Most of us, however, live increasingly indoor lifestyles and this, in combination with disproportionate fears about sun exposure and increased sunscreen use, has led to documented increases in vitaminD-deficiency bone disorders such as rickets, osteomalacia and osteoporosis.
But vitamin D and sunlight may be important to human health in ways unrelated to their effects on bone. Throughout the world, vitamin D deficiency has been linked to the development of cancers of the prostate, breast, ovary and colon, and to lymphoma. It is also implicated in a number of immune disorders such as type-one diabetes, rheumatoid arthritis and multiple sclerosis. The stimulation of alpha-melanocyte stimulating hormone (the substance that controls skin pigment) is directly tied to a range of nervous-system functions, including sex drive, appetite-suppression and a sense of wellbeing, and has a role to play in relieving depression and lowering blood pressure.
Although doctors and scientists are supposed to possess the ability to weigh issues from a risk/benefit perspective, no such balance currently exists when it comes to sun exposure. Factor in the benefits of regular sun exposure, and an alarming picture emerges. In the US the number of deaths from skin cancer is believed to be in the region of 10,000 per year. But in 2003, at the US National Institutes of Health’s ‘Vitamin D and Health in the 21st Century’ conference, William B Grant, a solar-radiation expert and former Nasa scientist who is now director of the Sunlight, Nutrition and Health Research Center in California, stated that lack of vitamin D accounts for 45,000 cancer deaths and 165,000 new cancer cases in the US annually. Several published studies suggest his figures are accurate. Speaking in the UK recently, Grant said that while malignant melanoma due to intense sun exposure claims around 1,600 British lives annually, 25,000 lives are being lost due to inadequate sun exposure.
Cancer Research UK might argue that it has never recommended staying out of the sun completely. But this is hard to reconcile with its acquiescence with headlines that shout about ‘deadly epidemics’. Nor does it square with the totality of SunSmart advice, which, followed to the letter, would prevent adequate vitamin-D production. Nowhere in the SunSmart ethos is there acknowledgment of the benefits of regular, deliberate sun exposure, full disclosure of the health risks of avoiding the sun or suggestions on how to make the most of the sun whatever your individual skin type and geographic location.
While the British government and Cancer Research UK continue to plough the same tired old furrow, there is a glimmer of hope elsewhere. Earlier this year, a coalition of organisations in the Antipodes, including the Australian and New Zealand Bone and Mineral Society, Osteoporosis Australia, the Australasian College Of Dermatologists and the Cancer Council Australia, produced a small but important document reviewing the risks and benefits of sun exposure. It concluded that daily sun exposure is both protective and desirable. At the same time, the Australian and New Zealand Bone and Mineral Society, the Endocrine Society of Australia and Osteoporosis Australia issued a remarkable position statement, published in The Medical Journal of Australia, acknowledging the need for deliberate sun exposure to counter the growing problem of vitamin D deficiency among Australians.
These are bold concessions from a region known as the ‘skin-cancer capital of the world’, and they open the door for the UK health authorities to finally admit that a decade-long campaign focusing solely on the ‘dangers’ of sunbathing has caused more harm than good. The collective mea culpa required may leave a bitter taste in the mouths of those concerned, but it is now urgently needed to prevent large numbers of us dying for want of a bit of sun.
Sidebar: The Epidemic That Isn’t
The two most common forms of skin cancer are basal-cell carcinoma and squamous-cell carcinoma. In some cases squamous-cell carcinoma can be disfi guring, but these cancers, which rarely spread to other sites in the body, are common and treatable and are referred to as non-malignant or non-melanoma skin cancers (NMSC).
Malignant melanoma is a rare but aggressive form of skin cancer. It originates in the melanocytes (the cells that produce pigment) and produces characteristic dark, fleshy moles on the skin. Melanoma can spread to the lymph nodes and, from there, to other parts of the body such as the lungs, liver, brain or other organs. As a result, it can be fatal to humans.
Diagnoses of all types of skin cancer, but especially malignant melanoma, have increased in recent years. Dr A Bernard Ackerman says this is in part due to the fact that the criteria for what constitutes a suspicious skin growth ‘clinically and histopathologically, are diametrically different from those 30 years ago’. In fact, medicine appears to have invented a whole new class of suspicious growth – the ‘premalignant’ mole.
Changing the definition of skin cancer means that small, non-symptomatic moles that would never have raised an eyebrow in the doctor’s surgery years ago are now diagnosed as pre-cancerous and treated aggressively. The resulting ‘cures’ are often celebrated as evidence that we are winning the war against skin cancer.
Interestingly, when organisations such as Britain’s Department of Health and the World Health Organization compile their statistics on the incidence of skin cancer, figures for NMSC are excluded. Officially, this is because the figures are unreliable and incomplete. But Cancer Research UK says: ‘NMSC is often excluded from cancer incidence statistics because it is usually much less serious than other types of cancer.’ In fact, more than 95 per cent of victims suffer no lasting health effects from NMSC.
Nevertheless, rates of NMSC are routinely included in statistics released to the media, and doing so swells the fi gures [for skin-cancer incidence] by as much as 1,000 per cent. For instance, while there were 70,038 cases of ‘skin cancer’ in the UK in 2001, only 7,630 of these were malignant melanomas.
On a global scale, when you compare the incidence of different types of cancer, the ‘epidemic’ of skin cancer is hard to take seriously:
- Lung – 1.2 million
- Breast – 1 million
- Colorectal – 940,000
- Stomach – 870,000
- Liver – 560,000
- Cervical – 470,000
- Oesophageal – 410,000
- Head and neck – 390,000
- Bladder – 330,000
- Malignant non-Hodgkin’s lymphoma – 290,000
- Leukaemia – 250,000
- Prostate and testicular – 250,000
- Pancreatic – 216,000
- Ovarian – 190,000
- Kidney – 190,000
- Endometrial – 188,000
- Nervous system -175,000
- MELANOMA – 133,000
- Thyroid – 123,000
- Pharynx – 65,000
- Hodgkin’s disease – 62,000
Sidebar: What You Can Do
In Britain, in particular, it pays to be opportunistic about sun exposure. Frequent short exposures are better than prolonged exposure. Consider these points:
- In the UK in the summer, 15 minutes of unprotected sun exposure on arms, legs, hands and face each day can promote optimal vitamin-D synthesis. In the winter, you may need to accumulate as much as two to three hours per week of exposure.
- Use the UV index positively. The index uses a global scale of one (low) to 11 and higher (extreme) to illustrate the amount of UV radiation at ground level when the sun is at its peak. Commonly, it is used to calculate how much harm the sun will cause in a specific amount of time. In the UK, the UV index rarely goes above a moderate six. According to the Health Protection Agency, this means the risk of burning during less than one hour of unprotected exposure is generally low for all but the most fair-skinned people (see ‘Solar Index’ information at www.hpa.org.uk).
- If you are going to be out in the sun for a long time, get at least 15 minutes of unprotected exposure first; then put your sunscreen on.
- Clothing also provides useful protection, and most summer clothes provide an SPF of more than 10. Specially designed clothing (reputed to block UV rays) is not only expensive; it’s unnecessary. The average T-shirt provides an SPF of seven. Fabrics dyed black, navy-blue, white, green or beige provide the highest SPF.
- Diet can be protective. Last year, the US National Institutes of Health concluded that people whose diets feature foods rich in vitamin D and carotenoids (vitamin A-like substances found in deeply coloured fruits and vegetables) also have a low risk of developing melanoma.
- Get informed: Michael Holick’s book The UV Advantage provides useful, accessible information on the benefits of sun exposure.
- If you must use a sun cream (for instance, if you need to be outdoors for prolonged periods of time) choose one that contains a physical sun block such as zinc oxide or titanium oxide, which works by reflecting UV radiation away from the skin. On current evidence, these are safer than chemical sunscreens, which absorb UV, thus keeping it nearer the skin.
- Mineral-based sun blocks are also less easily absorbed into the skin and are not associated with oestrogenic effects in the way that sunscreening chemicals such as benzophenone-3, homosalate, octyl methoxycinnamate and octyl dimethyl-PABA are. Other sunscreening chemicals to avoid include isotridecyl salicylate, octyl salicylate and octocrylene.
- Don’t equate high SPF with high quality. Some chemical sunscreens can be harsh on the skin, breaking down its natural protective barrier and leaving it more vulnerable to sun damage over the longer term. The higher the SPF, the more chemicals the product will have in it. Provided you don’t skimp when applying cream, and reapply often, few of us need an SPF higher than 15; for most of us SPF eight is adequate. Look for sunscreens that make use of vegetable-oil bases (rather than those that use mineral oils or silicones) and those that avoid using preservative such as parabens, which are also oestrogenic. There is some evidence that natural ingredients, such as plant oils and vitamins E and C, may enhance the ability of skin cells to repair cellular and DNA damage caused by UV exposure. Consider those made by:
- Green People: www.greenpeople.co.uk
- Weleda: www.weleda.co.uk
- Dr Hauschka: www.drhauschka.com
- Yaoh: www.yaoh.co.uk
- Neal’s Yard: www.nealsyardremedies.com
- Aubrey Organics: www.aubrey-organics.com
- Ecolani: www.ecolani.com
This article first appeared in the July/August edition of the Ecologist
