We are living in a time of a vitamin D deficiency epidemic in more northerly climes. Vitamin D is the sunshine vitamin. Cholesterol is converted to vitamin D when sunlight contacts the skin.
Why the epidemic?
Firstly, concern over skin cancer means people are covering up from the sun too much. It is important not to burn, but just as important to get direct sun contact with the skin to make vitamin D. Secondly, people who work inside just don’t get to see the sun enough and then come winter, serious vitamin D deficiencies can show up. Thirdly, children are watching TV and playing computer games rather than playing outside. Fourthly, we eat less of the foods that are naturally rich in vitamin D like wild oily fish and liver. Finally, climate change means more cloud cover in summer months than before.
A hormone not a vitamin
Cholesterol (yes that much maligned substance) is converted into 7-deydrocholesterol, which in our skin cells is converted into the hormone vitamin D. This action is prevented by sunscreens and clothing which block most of the necessary UVB rays necessary for this conversion.
Vitamin D is soluble in lipids, not water. This means it will accumulate in the body. So vitamin D toxicity is possible if you take it as a supplement. However the body’s own production of vitamin D will stop when enough has been made.
This hormone plays a number of roles in the body. Importantly it regulates the function of hundreds of genes. Up to as much as 5% of our genome in fact.
Vitamin D and bones
Rickets, osteomalacia and osteoporosis are caused by a vitamin D deficiency because of the role it plays in regulating the uptake of calcium. When blood serum calcium is low the body will take calcium from bone. This stimulates the action of vitamin D which increases calcium absorption from the gut. If there is a vitamin D deficiency this extra absorption will underperform and the calcium deficiency will result in a fall in bone density.
Cases of Rickets (a childhood disease where bones don’t develop properly), have doubled here in the UK since the 1990’s.
Vitamin D and cancer
Find out about the wide range of other diseases are associated with a lack of vitamin D and our top Wildervore tips get making sure you get enough to avoid them.
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