Pain and one tiny unscientific conclusion

I just had to respond to Lynne McTaggart's What Doctors Don't Tell you blog on pain: this was the comment I posted.

Was very interested to read this timely posting on an important issue for patients as I agreed with 95 per cent of all you said.....until you made the comment about vitamin D. It is a very fashionable conclusion. But who benefits if everyone (apparently) needs to supplement their vit D intake? The health supplement producers, and particularly a large lobby of vit D producers, that's who.

If vitamins are defined as chemical substances that the body cannot produce itself but which must be ingested for correct functioning of the body, then why is vitamin D produced by the body (in several complex forms) through the action of light on skin and eyes? Maybe because it is not a vitamin and needs detailed investigation?

Many research studies recently have concluded there is a link (or correlation) between low levels of 25-hydroxyvitamin D (the most commonly and simply measured form of vit D) and pain/underlying disease. But note the word 'correlation'. The cause meanwhile could be one of at least two options: pain/underlying disease causes low levels of vit D; or low levels of vit D cause pain/disease. Too often it is claimed that a proven correlation has the latter cause. I am not just unconvinced but find this repeated mistaken conclusion totally unscientific.

Also, how come this study below (and others) showed that people with long-term avoidance of light still maintain normal vit D levels in their bodies?

http://www.ncbi.nlm.nih.gov/pubmed/9418761