What's the Big D-eal: 9 Things you didn't know about Vitamin D!

It’s that time of year again, the nights have drawn in and the Sun has got his woolly hat on.

As well as helping support better mood, keep the chill from our bones and provide us with a delightful tan (well, unless you are like me who seems to reflect the Sun) those magnificent rays are also essential for the creation of the very important & essential vitamin D.

Vitamin D is often considered as more of a hormone than a vitamin because of the wide-ranging effects it has on many systems in the body. It is unsurprising that low levels of vitamin D can affect everything from mood state, bone health, hormone levels and much more.

Vitamin D is synthesised as a response to sunlight UVB exposure and involves interaction with a type of cholesterol in our skin, this is then converted to ‘pre-vitamin D’ and then transported to the liver for conversion into a storage form of vitamin D. From there it is transported to the kidneys and converted to the active form of Vitamin D called 1, 1,25-dihydroxyvitamin D [1,25(OH)2D], or calcitriol.

9 Interesting things to know about Vitamin D?

  1. Although we know the effects of vitamin D deficiency it is still debated what level deficiency should be determined medically. Common consensus seems to be that around 40% of northern Europeans have sub-optimal levels of Vitamin D with around 10-15% being severely deficient.
  2. Vitamin D in its supplement form (D3) often comes in two measurements, micrograms (mcg or μg) and international units (IU). 25mcg is the equivalent of 1000iu and the suggested amount to supplement is in the region of 20-80iu per kg of bodyweight.
  1. Despite being called a Vitamin, it has been argued that Vitamin D is more or a hormone, or at least a prohormone due to the wide-ranging regulatory effects it has in the body.
  1. Other mammals activate vitamin D in their fur instead of skin. Having ditched (most) of our fuzz for clothes this is what puts us at risk of deficiency due to lower surface area exposure.
  1. The fact that we need to wrap up warm in our beautiful UK winters due to the lack of fur, or fur not doing enough of a good job to adapt to cold climates in our evolutionary ancestors the fact we have big ‘ole brains meant we could overcome this through our use of animal furs to spread our wings across the cold parts of the globe has led to an increased risk of vitamin D deficiency.
  1. In warmer regions, with less need for clothing this puts people at risk of skin cancer, so we can’t blindly burn ourselves to a crisp for the same of vitamin D. The safer bet is to stay covered, use sunscreen and use supplementation to top up our needs.
  1. Having darker skin helps offer some protection against UV rays and skin cancer (there is still a risk to sun exposure to be crystal clear on this point) but reduces vitamin D synthesis. This isn’t usually an issue in sunny climates but those with darker skin pigmentation may be at increased risk of vitamin D deficiency in less sunny parts of the world.
  1. Looking through bone records of our ancestors has shown that vitamin D deficiency has been around for a long time. Some of these effects were mitigated by a diet rich in fish and whale blubber in artic climates and by chance the domestication of animals, particularly fowl, helps with this as eggs and meat do offer at least some protection. However, this was clearly not easily accessible to all during large periods of our history so disease like rickets were very prevalent in large parts of the population.
  1. Although we store vitamin to a certain level. This is not enough to sustain us through winter and compensate for lack of sun exposure. Even with a vitamin D rich diet this is often not enough to keep us at optimal levels, so supplementation is essential for those who want to really optimise their health and performance.