Thursday, 29 July 2010

Vitamin D

Another episode from BBC Radio 4's Case Notes, this time on Vitamin D:
  • After a cold winter with little sunlight lack of vitamin D is common, but how do you know if your levels are too low? Traditionally lack of Vitamin D is linked with poor bone health, but new studies suggest that milder deficiency may also be linked to asthma, some cancers and diabetes. Dr Mark Porter investigates and hears from a night shift worker who had such excruciating pain in her hands she thought that she had arthritis - when her doctor checked for vitamin D levels, 3 weeks of supplements cured the pain.
They discuss the role of vitamin D in diabetes, cancer (of the colon), colds, flu, TB and the immune system in general (including allergic disorders like hayfever, exzma and asthma).

With TB, it is suggested that in immigrants to the UK from the African continent, TB is dormant, but once their vitamin D levels fall, it activates.

The bit about hayfever is quite interesting.  I have not had hayfever this year and I used to get it sporadically throughout summer.  I had put it down to my paleo diet rather than supplementation with vitamin D - but this last year I have supplemented with 2500 IU over autumn and spring and 10000IU most days over winter.

This also raises a point I have been meaning to blog about for a few weeks.  Historically when I have been bitten by mosquitos, the bitten area has ballooned up.  But whilst on holiday in France earlier this year, I got bitten a few times and although the bite itched for a day or two, there was no gross inflammation unlike previously.  So what is the cause?  Vitamin D supplementation?  The paleo diet leading to a refined immune response?


Neonomide said...

I think Vitamin D is simply a "piece in a puzzle".

I have Crohn's Disease and got it 90%+ remission with Vitamin D only. I even had a break of it for many months and just now sun is my only source. Getting more "paleo" has been even better.

What I think is that inflammatory symptoms in for example arthitis are part because impaired Vitamin D, Omega 3/6 thing and grain intolerance + some less known reasons. Epigenetics are almost certainly involved too.

You have a great blog, just figured it out from Grace. ^^

Asclepius said...

I think Vitamin D is simply a "piece in a puzzle".

I am with you on this. Modern medicine treats 'numbers' which in and of themselves, are limited in what they indicate about the health of the system as a whole.

For example, only today it has been announced that taking calcium supplements increases heart attacks!

A 'paleo life' simplifies the whole process - weight bearing activity and dietary calcium are optimal to improve bone density and has myriad other benefits (exercise = endorphin release etc...). No need to pop a pill.

I am glad 'paleo' is working for you!

Ken said...

Yes that sounds plausible - but it's wrong. The huge state of the art July 2010 study Common genetic determinants of vitamin D insufficiency: a genome-wide association study found that none of the genes they identified are linked with skin pigmentation.

Confirmation of that interpretation in an article Here :- ” the accompanying (Lancet) editorial points out, it is somewhat surprising that none of the genes identified are linked with skin pigmentation”

A systematic review of the association between common single nucleotide polymorphisms and 25-hydroxyvitamin D concentrations
"We speculate that recently identified U-shaped relationships between 25OHD concentrations and disease outcomes (i.e. increased risk at both high and low concentrations) may reflect a mixture of genotype-defined subgroups."

'Genetics to Blame for Vitamin D Deficiency?'
"Researchers conducted a genome-wide association study (Common genetic determinants of vitamin D insufficiency: a genome-wide association study) that involved almost 34,000 people of European descent from 15 different studies. They used radioimmunoassay and mass spectrometry to determine vitamin D concentrations and found that variants at three genetic sites, or "loci," were significantly associated with vitamin D concentrations. The presence of harmful alleles at three "loci" more than doubled the risk of Vitamin D insufficiency."

Maybe non-whites are the ones who benefit from doubling their vitamin D levels ? Nope - Vitamin D, Adiposity, and Calcified Atherosclerotic Plaque in African-Americans "positive associations exist between 25-hydroxyvitamin D and aorta and carotid artery CP in African-Americans"

Many people are naturally low in vitamin D, forcing vitamin D levels up by taking supplements can only do harm. If you think you can improve yor health by conforming to the advice of Holick or - God forbid - that of Hollis, Cannel & Co at the vitamin D 'Council' who recommend (>50ng/ml) then you are in for an unpleasant surprise.

Vitamin D and homeostasis

Mad dogs and ....

Asclepius said...

Hi Ken, thanks for posting. I will have to take a look through those links....

Methuselah said...

Wow, the comments in that Mad Dogs... post are rich with information sources and expert opinion. My conclusion is that this is far from clear cut. It's easy to throw studies around saying supporting one side or the other but there are invariably factors that could render them impotent, as the comments show. Tow that caught my eye were the increased cereal consumption affecting D absorbtion and the effects of industrial farming on the content of D in animal products. All I know is that since my wife started supplementing she's not been ill. And that's saying something. As far as I can tell, it's the only significant variable over that time. Anecdotal, yes, but in the absence of a degree in enterpretting scientific papers, it's my best source of evidence.

Methuselah said...

...and washing with soap...

Asclepius said...

You know I have not washed my hair with shampoo for over ten years - it was a tip I got from Take That in about 1994!

As for soap, yep, even that was dispensed with several years ago - apart from discreet use under the armpits and around the groin.

As for Ken's comments and links - there is much to explore. I have a post in gestation about the body's 'gates' and how we over ride them, and how, in fact, to some extent paleo re-enactment can be optimal as it allows these 'evolved gates' to do their job.

Methuselah said...

Ditto on the shampoo. I had a spell of using it again earlier in the year, but I am now shampoo-less and just soap for the 'special' places ;-)