Saturday, July 4, 2009

Vitamin D

It appears that Vitamin D is a surprisingly important vitamin. I'd always thought you just needed a little bit of sun exposure and you'd get enough. But maybe not. Deficiency seems to be surprisingly common. Evolutionarily it makes a certain amount of sense, as we evolved being outside all day wearing not very much. Now we huddle in offices and, particularly in winter, barely get any direct sunlight.

I first came across this idea thanks to a post by Dennis Mangan. Not long after, someone with CFS emailed OzME (an Australian ME/CFS email list) reporting that their doctor had tested their Vitamin D levels and that they were low. They recommended everybody get theirs checked, in case they were deficient, because it is involved in all sorts of body processes, especially immunity. Seems like the sort of thing that you don't want holding your immune system back, when it's got a hard job to do.

A good resource about all of this is the Vitamin D Council. They have some good articles on checking for deficiency, and how Vitamin D could be used to treat swine flu. There is lots more stuff on how Vitamin D is involved in depression, cancer and autism. Dennis Mangan has a bunch of interesting posts on the issue which give a good overview.

And here is an interesting article on how much money could be saved if everyone in Northern Europe got enough Vitamin D (quick answer: about 18% of total health expenditure!).

I saw my doctor the other day and she was quite happy to test my Vitamin D levels. She said she's doing more and more of it, and that a surprising number of young females are deficient. She said it should be up around 80ng/mL, but didn't suggest as big doses as the Vitamin D Council.

So in a few days I'll know if that is a factor in my CFS puzzle!

What I haven't worked out is if animals synthesise Vitamin D from sunlight, and if so, how do they manage it when they are covered in fur?


  1. My mate found the answer for me:

    Animals Form Cholecalciferol In Their Fur

    Fur bearing animals and many birds make cholecalciferol in their fur or feathers since sunlight can not get to their skin. Interestingly, mammals and birds then eat the cholecalciferol by licking their fur (grooming) or rubbing their beaks on their feathers (preening). So, when you take cholecalciferol by mouth, you are doing what a number of other mammals do!

  2. Hey G,

    Also, we humans actually form active vitamin D from a couple of source; diet and UV sunlight. So we can acquire the primordial product (cant remember the chemical name off the top of my head) without sunlight, as long as we have the adequate amounts of the precursor in our diets in the form (i think) of fish and nuts and legumes etc.

    THen, to get active vit D, the 2 precursors require firstly liver enzymes, then kidney enzymes. So if either organ is dysfunctional, you might not have adequate active vitD.

    VitD is important for calcium homeostasis. Perhaps furry animals can produce active vit D through their diet as well...??

    Nic G