Week 14 - Vitamin D, cancer and sunshine

One of our local newspapers has picked up on a debate concerning the supposed “magic bullet” of Vitamin D. Oliver Gillie, who runs the non-profit organization Health Research Forum, has been expounding his theory that we have got it all wrong: Sunlight is good for you, and in fact exposure to sunlight is correlated with a reduction in various cancers, and also protects us from upwards of 25 different diseases!

Oliver Gillie is a freelance medical researcher and writer. Formerly he was medical correspondent of The Sunday Times, then medical editor and later special correspondent of The Independent newspaper. He has a BSc and PhD degrees from Edinburgh University where he studied genetics and developmental biology. Gillie says:

Human beings need regular exposure to sunlight on their skin so that they can make vitamin D which is vital for health. Yet the British government advises the public to “cover up, keep in the shade”. This advice is mistakenly modelled on a programme developed in Australia where a tropical to Mediterranean type of climate provides much more vitamin D. Faulty calculations made by the National Radiological Protection Laboratory have misled UK government advisers into thinking that casual exposure of hands and face to the sun in the UK will provide sufficient vitamin D for health.

In fact casual exposure does not provide enough vitamin D in the British Isles and the majority of people in the UK have an insufficient level of vitamin in the blood, particularly in winter.The risk of skin cancer from sun exposure is much smaller than the public has been led to believe while the risks of vitamin D deficiency or insufficiency, which are seldom mentioned, are now known to be very substantial. Insufficient vitamin D at crucial times of life or for prolonged periods appears to increase the risk of several cancers, including breast and bowel cancer, diabetes, high blood pressure, schizophrenia, multiple sclerosis and many other chronic diseases including even tooth decay.

The UK government campaign for prevention of skin cancer, led by Cancer Research UK, has in effect been a campaign against sunbathing. Perhaps its most misleading aspect has been the slogan: “There is no such thing as a healthy tan”. This ignores evidence that people who have a deep tan are less likely to get melanoma, the most serious form of skin cancer. While people who get sunburnt, an indication of extensive exposure to the sun, are less likely to get multiple sclerosis or prostate cancer. Oliver Gillie’s report, Sunlight Robbery, explains how government policy has gone badly wrong and urges people to sunbathe whenever they can, wearing as few clothes as possible, while taking care not to bake or burn.

I have read the documents on his website, and frankly I am not convinced. It is a fact that people living in Europe do not see the sun very much, and it may be that this leads to low vitamin D levels. However, there are quite a few problems with Gillie’s suggestions.

I am always worried by someone who has the answer to everything, more so when he insists that he and a small group are the only people who see the truth, and that the rest of mainstream scientists are consciously ignoring what, to Gillie, are self-evident facts. The document Sunlight Robbery: Health benefits of sunlight are denied by current public health policy in the UK is filled with comments such as “Evidence that these diseases are caused, at least in part, by a deficiency of sunlight and vitamin D has accumulated at an accelerating pace over the last 10 years but is not well known, even to professional scientists,” “Present government policy on sunlight is the product of limited specialist knowledge, particularly of dermatologists.”, and “Sunlight may have other benefits, not at present fully understood.”

Gillie and others make the point that a certain level of exposure to the sun, producing a tan, seems to protect against melanoma and other skin cancers. However, Kaskel et al have this to say (2001) “Sunburn in childhood and increased sun exposure during annual holidays in sunny areas should be avoided. In contrast, outdoor activities in childhood, including soccer and gardening, should be encouraged because they are associated with a lower risk of melanoma formation.”

When I was young (a long time ago…), we did not have television, computers, video games, etc. I grew up in Johannesburg, South Africa, at approximate latitude 26° S. I lived quite far from school, and had to ride a bike to and from school every day .. And most of my friends lived near the school, so I was always out and about on my bike. In summer we spent many happy hours in the sun at swimming pools, and I recall getting seriously burnt on many occasions.

Fast forward a few years, and I graduated to a motor car. One spends quite a lot of time in the car, although this is usually in the early morning and late afternoon traffic, when the sun is less intense, but also at a lower angle. We drive on the left, so I had more exposure on the right hand side of my face … And this is precisely where I have had many skin problems, with two melanomas over the last few years.

The problem I see with Gillie’s recommendations, even if his conclusions are correct, is: How is anyone going to translate this into action, without increasing the incidence of melanoma? Skin types vary widely, so what is acceptable for you may be dangerous for me. The amount of exposure to the sun depends on the latitude, altitude above sea level, angle of the sun, pollutants in the atmosphere, and so on, making it almost impossible to provide people with a rule of thumb.

I see a very real danger that each person will interpret his/her situation subjectively, and run the risk of getting it wrong! As a simple example, when I was young, we would spend hours at the public swimming pool, trying to attract the attention of girls… (We hardly ever succeeded…) But the result was that we got awfully burnt! Although we knew better, this did not stop us – We just ignored the consequences, as kids usually do. And in those days there was no sunscreen, and no awareness of melanoma.

No Mr Gillie, I think you have not thought this through properly. It is dangerous to make recommendations without taking into account human nature. For example, what about the large numbers of Brits who use cut price airlines to spend a week in the Mediterranean sun in mid-summer? None of these boys and girls have built up a tan, and then suddenly expose their skin excessively for 6 days before flying home. Seems to me to be a perfect formula for developing melanoma in 20 years time.

Postscript: Don't get me wrong: I am all in favour of large numbers of young ladies suntanning in the parks at lunchtime, wearing as few clothes as possible...

For anyone interested in reading more:

Health Research Forum: http://www.healthresearchforum.org.uk

CANCERActive article: http://www.canceractive.com/page.php?n=509

Quackwatch: http://www.quackwatch.org
and particularly the page A Special Message for Cancer Patients Seeking "Alternative" Treatments, at http://www.quackwatch.org/00AboutQuackwatch/altseek.html