Earlier today, I came across this story in the on-line version of the Daily Mail (UK) which reports on a theory relating to why the Scotland enjoys a preponderance of redheads. The theory, which the originator herself describes as ‘speculation’, is that a combination of the ‘bad weather’ in Scotland, coupled with a genetic mutation, led to burgeoning in the numbers of those with red hair. What the piece does not mention, however, is why such a mutation should exist and then persist.
When a genetic mutation occurs there is sometimes a good reason for it: some benefit may be had from that mutation. So, what benefit might there to be had from having red hair? There probably isn’t one. But there probably is a significant advantage to be had from having the pale skin tone that invariably goes with red hair.
The action of sunlight on the skin can lead to the making of vitamin D – a nutrient which is linked with an ever-growing list of benefits for health including a reduced risk of multiple sclerosis, heart disease, diabetes, and several forms of cancer. Generally speaking, the lighter the skin tone, the more vitamin D is made for a given amount of sunlight. In other words, having pale skin is potentially advantageous, particularly in locations where sunlight tends to be in short supply (like Scotland).
And all this reminds me of a conversation I had recently with Oliver Gillie, a writer and research based in the UK who has a keen interest in vitamin D.
During our conversation, Scotland came up. Here in the UK, the Scots have a famously poor health record. This is very often put down to factors such as lack of exercise, alcohol excess and a generally poor diet including ‘deep-fried Mars bars’, as well as a certain social and class-related factors. However, according to Gillie, social and lifestyle factors such as these do not fully account for the health disparities that exist between the Scotland and more southerly parts of the UK.
It occurred to Gillie that at least one ‘missing’ factor might be vitamin D. Could the relative paucity of sunlight in Scotland lead to generally levels of vitamin D, in turn putting the Scottish at heightened risk of chronic disease?
Gillie then undertook an extensive review of the literature to see what evidence there is to support this theory. He distilled his extensive research into a book, which is available for free download here. In this book Gillie, in my view, makes a hugely compelling case for both the link between low vitamin D status and disease in Scotland. He supports his case with over 500 scientific references.
Among other things, Gillie draws our attention to the apparent folly of Cancer Research UK’s SunSmart campaign, which generally urges people to be wary of the sun. As Gillie points out, this advice may well be adding to the seemingly vast numbers of people who have suboptimal levels of vitamin D.
While too much sunlight can burn the skin and increase the risk of skin cancer, shying away from it has other hazards. Gillie promotes safe sunbathing and sun exposure (and so do I). While burning is to be avoided, he advocates that individuals generally get as much sun exposure as they can. His specific tips about how safe and effective sun exposure can be found in the book (see page 56 under ‘Sunbathing – the SunSafe advice’).
Scotland’s Health Deficit: An Explanation and a Plan by Oliver Gillie