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Vitamin D: Time to Get Savvy With Sunshine

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Can there be hotter property in the field of nutrition right now than vitamin D - the 'sunshine vitamin'? There's been an explosion of vitamin D research over the last decade and it's completely revolutionised our view of this previously unremarkable vitamin. We've long since known that vitamin D is important for healthy bones (you need it to absorb calcium for a start), but vitamin D has now burst on to the scene in dramatic fashion, with evidence mounting that it may play an important role in preventing a plethora of modern day afflictions, such as common cancers, heart disease, diabetes, arthritis, multiple sclerosis, and more besides. Recently, researchers found that there was an extensive need for vitamin D in the body, with it significantly effecting the expression of 291 genes - primarily involved in inflammation, autoimmune responses, cardiovascular functioning and cellular growth (1). This is in line with previous analyses which estimated that 0.5-5% of the total human genome is influenced by the actions of vitamin D.

Staggering stuff, to think that one single nutrient affects so much. Findings that resonate all the more loudly with the growing realisation that a large proportion of the UK population (and we're not alone - many other countries are in the same state) have low levels of vitamin D, especially through the winter months (2). It poses a big question; is this putting the health of virtually the whole population in jeopardy?

The problem with vitamin D is that there are very few good dietary sources (oily fish probably being the best) and we simply can't rely on food to meet our needs. We've always - and still do - get the vast majority of our vitamin D from sun exposure. But justified concerns about skin cancer have turned us into a nation of sun dodgers. Fervent public health messages to avoid the midday sun, always cover-up, or ply every last square inch of our skin with copious amounts of sun block (a sun block of SPF15 will reduce vitamin D production by 98%), have played their part in depriving us of our most abundant source of vitamin D.

This begs the big question: have we gone too far? Incredibly, in sun-drenched Australia, more than 80% of dermatologists were found to have low vitamin D levels (3). In fact, their vitamin D levels were even lower than elderly patients in a Melbourne hospital! It's a mad stat, and leads us to ask; have we simply become too 'sun smart' for our own good?

Here's the rub. Key organisations such as the British Association of Dermatologists, Cancer Research UK, Diabetes UK, the Multiple Sclerosis Society, the National Heart Forum, the National Osteoporosis Society and the Primary Care Dermatology Society don't think total sun avoidance is the way to go. Getting out for just a few minutes - without sunscreen - in the middle of the day will enable you to make substantial amounts of vitamin D.

It's important to say that there are a lot of factors that can affect your ability to make vitamin D from sunshine, such as your age (our ability to make vitamin D declines with age), skin colour (melanin absorbs UVB), and even your level of body fat to name but a few. But to offer an example, if we take someone who is young and white, a mere 4 minutes of sun exposure to the arms and legs will produce a satisfying 1,000 IU of vitamin D. So you can begin to see how a 'little and often' approach to sun exposure throughout the summer months can readily bolster your vitamin D levels without undue risk of skin cancer.

But be under absolutely no illusion; more is not better when it comes to sun exposure. That's totally flawed thinking. It's never, ever, a good idea to redden or burn in the sun (like you needed to know that lobster-pink isn't a good look...). Excess sun exposure will readily damage and age your skin and aggressively promote skin cancer. And ironically, the skin will shut down its production of vitamin D anyway to avoid making too much.

With a modicum of common sense, a little and often dose of 'safe sun' is a perfectly plausible proposition to secure your vitamin D levels this summer, and with it enrich your levels of one of the most profoundly important vitamins for health, wellbeing, and disease prevention.

(1) Hossein-nezhad A, Spira A, Holick MF (2013) Influence of Vitamin D Status and Vitamin D3 Supplementation on Genome Wide Expression of White Blood Cells: A Randomized Double-Blind Clinical Trial. PLoS ONE 8(3): e58725

(2) Hyppönen E, Power C (2007) Hypovitaminosis D in British adults at age 45 y: nationwide cohort study of dietary and lifestyle predictors. Am J Clin Nutr 85(3):860-8

(3) Czarnecki D, Meehan CJ, Bruce F (2009) The vitamin D status of Australian dermatologists. Clin Exp Dermatol 34(5):624-5

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