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’).
Resources:
Scotland’s Health Deficit: An Explanation and a Plan by Oliver Gillie
I think you’ll find that people with black hair have more soot – I mean, carbon – in their bodies…
Seriously, while I can’t approve of deep-fried Mars bars, I wonder if that sort of thing is really much worse than supposedly health-giving foods like cereals and pulses. If there was one single dietary factor that would give a bigger health benefit to the Scots than anything else, would Vitamin D supplementation be the one?
Let’s look at another aspect shall we? The Red hair. Did you know that Blondes have more Sulpher in their bodies? Well, red-heads have more copper.
I should think a look into ‘copper’ and it’s roles in the human body may get this line of thought into a deeper understanding here….
How does freckling relate to this? As a red head with Scotch-Irish descent, I’ve got the hair and the freckles to go with it. The freckles increase in pigmentation and density with increased sun exposure, but some skin is always left unpigmented. Maybe this isn’t just some random mutation either.
Also, redheads are supposedly different in their sensitivity to various drugs, presumably through some variant on P450 or some such drug degrading enzyme. I don’t know if anyone has ever studied it though.
SassaFrass88
Do you have a reference regarding the higher levels of copper in red hair?
I recall an old article by Loren Cordain on the issue of “extreme epidermal depigmentation.” The reason for the light skin was, yes, vitamin D metabolism. It was a problem with the phytates in grains, their effects on bone formation, and their resultant selection toward people with lighter skin. I assume darker skinned mothers died in child birth due to smaller birth cannals, or people simply died due to rickets.
You see a lot of red heads in Yorkshire, possibly descended from the Vikings – health in Scandinavia must provide a relevant comparison?
Dr Briffa, I think you have ‘stolen’ my theory that lighter skinned people make more vit D or need less sun for healthy bones. I thought of this when teaching adaptation to science students. As a white (very) skinned person I got badly burnt in light in Scotland when it wasn’t even hot.
However as I Glaswegian myself I know that generally speaking SCotland is more working class, has a high rate of alcoholism and smoking, high rate of drig addiction, poorer diet (in the towns) etc than the South.
We cannot see Vit D as a panacea
Hilda
Susan makes a good point. How does the proportion of redheads in other northern countries compare with that in Scotland?
I thought research of one sort or another explained the Scottish red hair as being a direct result of the invading Vikings, to whom the sun relationship was attributable.
The link between vitamin D status and Scotland’s poor health record is not in dispute but how did this come about? It can’t just be poverty. Growing up in real poverty in the nineteen forties and fifties meant as children we didn’t have many material possessions but we did have nutritious food, which was relatively cheap – oily fish, butter, cream, whole milk, eggs. Sweet rationing did not end til 1953. Certainly the green veg was hated by us kids but we had to eat it before we went off to play outside…..what has happened to all these sources of vitamin D?
The modern “low fat” mantra beloved by governments and medics which does not appear to be working in reducing obesity; the high sugar, high carbodhydrate diet of the many, the misinformation about cholestorol – leading to eggs and butter being rejected, the obsession with keeping out of the sun (what brand of sun block did Stone Age man use? Do kids still play outside in their local area? Have the playing fields of state schools been sold off to buy computers? What would the Vitamin D status be like of elderly residents in so called “Care” Homes?), the politics of food (fishing industry, argricultural practices)….I needn’t go on.
We accept that things have changed but what to do about it? Of the three ways to get Vitamin D – through diet, by conversion from sunlight through the skin or by taking supplements, if you live in Scotland, it looks like supplementation is the only sure way. But at what levels ? Is there any consensus on whether it is a vitamin or should it be reclassified as a hormone, as it seems to govern so many functions? If a vitamin, what are its most important co-factors? Is it magnesium? At what level does Vitamin A become a problem in Vitamin D absorption?
This Viking redhead source is rubbish.There are more redheads in Scotland than Scandinavia .did all the Viking come also the Romans noted the red hair in north Britain well before the Viking.scandinavian red hair comes partly from Britain .Also the Viking took many Irish brides with them to Iceland which is about 50% Irish genes now