Monday, December 22, 2008

Vitamin D

Some of the blogs I read have been paying a great deal of attention recently to Vitamin D. (UPDATE e.g. Matt here)

Stephan had a great post - Vitamin D: It's Not Just Another Vitamin

If I described a substance with the following properties, what would you guess it was?

-It's synthesized by the body from cholesterol
-It crosses cell membranes freely
-It has its own nuclear receptor
-It causes broad changes in gene transcription
-It acts in nearly every tissue
-It's essential for health

There's no way for you to know, because those statements all apply to activated vitamin D, estrogen, testosterone and a number of other hormones. Vitamin D, as opposed to all other vitamins, is a steroid hormone precursor (technically it's a secosteroid but it's close enough for our purposes). The main difference between vitamin D and other steroid hormones is that it requires a photon of UVB light for its synthesis in the skin. If it didn't require UVB, it would be called a hormone rather than a vitamin. Just like estrogen and testosterone, it's involved in many processes, and it's important to have the right amount.

I was reminded of this by a BBC Story today: Poor health 'due to wet climate'

Scotland's poor health record could be directly linked to a lack of sunshine, a scientist has said. Dr Oliver Gillie linked the "extreme" weather to vitamin D deficiency, which is caused by low exposure to sunlight. He has called for "urgent" government action to encourage people to take a daily dose of vitamin D to help tackle diseases such as cancer and MS.
I live in Scotland and - particularly at this time of year - there is little sunlight to be found!

Then I came across this:

What Does Vitamin D Have To Do With Your Back Pain?

There are a number of reasons for why vitamin D deficiency can cause chronic pain.
1. Vitamin D deficiency causes a reduction in calcium absorption.
2. Production of parathyroid hormone is increased to maintain blood calcium levels
3. Parathyroid hormone results in increased urinary excretion of phosphorus, which leads to hypophosphatemia.
4. Insufficient calcium phosphate results in deposition of unmineralized collagen matrix on the endosteum (inside) and periosteum (outside) of bones.
5. When the collagen matrix hydrates and swells, it compresses the sensory-innervated periosteum, resulting in pain.


Nathan said...

The previous two winters I had developed an inexplicable pain going up the left side of my neck that really made sleeping uncomfortable. Each year the pain started around Thanksgiving, peaked in January, and went away gradually as spring came (I live in Colorado). A few weeks ago, on Nov 8, I woke up with the same pain again. It was only then, the third time around, that I was struck by the seasonality of the pain and made the leap to it possibly being a sign of sunlight and vitamin d deficiency.

I haven't taken any kind of a vitamin for years, and gave up drinking (fortified) milk 18 years ago (I'm 36 now), so I probably have had little intake of D except for that synthesized from sun exposure during the brighter months.

I did some quick research on Vitamin D at the health/fitness sites I usually read (Conditioning Research, Mark Sisson, Gabe Mirkin, etc), I found the Vitamin D Council site -- and was supplementing with 2000 IU/day of Vitamin D within a couple of days.

The worst of the neck pain went away within a couple of weeks -- it had been difficult just to roll to a new position in bed and that was gone. Six weeks later now, and the residual stiffness is now totally gone, at the time in previous years when it had been the worst.

I'm really looking forward to spring when I can start getting some natural D again!

Chris said...

That is interesting Nathan. Thanks. I suppose the climate in Colorado - at least in terms of sunshine - is similar to Scotland. In the deepest winter here it gets light at about 830 and almost dark at about 3:30...which is depressing!

Methuselah - Pay Now Live Later said...

Chris - I've been chewing over the Vit D issue myself in recent weeks. Dr Eades has a fairly thorough chapter in The Protein Power Life Plan, but unfortunately this is mainly around the importance of sunbathing. I have made an effort to go out in a t-shirt when there has been some sun, but it's not always practical. I don't think Birmingham scores much better than Edinburgh in the sunshine stakes! One thing I did pick up on from the Eades book is that sardines are one of the few good dietary sources of vit D. I prefer not to take supplements, so I have been making an effort to have at least a few tins a week as well as a bit of sun where I can get it. Will be really interested to know whether any efforts you make in this regard improve your back pain.

Marc said...

Having grown up in Amsterdam I feel your pain ;-)
I used to bike to school in the dark and came home in the dark....usually in the rain.

Now that I have lived in the sunshine for about 8 years I can attest that the vitamin D issue is REAL. The older population thrives here (they are more active then other parts of the country, so that might be part of the equation) as they spend lots of time outside in the sun. Their skin might be a little more wrinkly and they have a sun spot or too, but to be playing tennis and sprinting when you're 78 (I'm good and this gent could still hold is own just fine) has to be an indication how important the sun actually is for us.
Thanks once again for the quality links.


Chris said...

Thanks guys

I do think that there is more to Scotland's poor health than the climate. The diet here is pretty poor in many areas, stress is high, often little exercise.....

Nathan said...


I'm in the Denver area and we are actually much sunnier and drier in the winter than people suppose. The mountains rise just to the west and are cloudier. However, we're at a high enough latitude (about 39.5 deg, just south of Madrid's latitude) that supposedly even noon time winter sun doesn't generate significant vitamin D. From what I've been reading you need to go down to 30 deg (about where New Orleans and Cairo are) for sunlight to generate vitamin D in midwinter.