The interview isn’t too long and does not go into great technical depth but is a great listen and I certainly learned a few things from listening to it.  I knew that there are two different sources of vitamin D, diet and production by the body due to exposure to sunlight.  I didn’t realise that animal and sunlight derived vitamin D is Vitamin D3 and invertebrate and plant derived vitamin d is Vitamin D2.

My colleagues have discussed the numerous conditions linked to Vitamin D other than the traditional role in calcium metabolism.  It seems that currently the mechanism of protection provided by Vitamin D is uncertain but there are several possible avenues being investigated.

Discussion touched upon the slightly problematic reference ranges.  The traditional reference range has been defined by analysis of a healthy population for the analyte and find the standard deviation and the mean.  The reference range is from -2 SD below the mean to +2 SD above mean. Or in other words, its the range which covers 95% of the popultation.  With Vitamin D, this produces a  limit of 25 nmol/L.  Recent evidence has suggested that people with a “normal” Vitamin D level are still risk of a variety of conditions.  There is evidence to suggest that limit 75 nmol/L provides protection against the various conditions that Vitamin has been linked with.  Like cholesterol, it seems that the reference range for Vitamin is based on health benefits rather than the traditional route.

One of the problems discussed regarding the analysis of Vitamin D is the link of standardisation and lack of agreed calibration material.  Numerous labs currently measure Vitamin D with an immunassay.  This approach has difficulty is differentiating between Vitamin D2 and Vitamin D3.  Techniques like liquid chromatography linked to a tandem mass spectrometer can provide measurement of Vitamin D2 and D3 but the equipment requires a considerable capital outlay and requires a high level of technical expertise.

As it stands, Vitamin D is being implicated as having a protective role in a considerable number of conditions with more probably yet to be discovered.  There are considerable hurdles to clear in the analysis of Vitamin D but is certain that Vitamin has a considerable role outside of its traditional role in calcium metabolism.

This was a really worth while podcast to listen to.  I have listened to two episodes and I will write these up soon.

Audio: http://media.aacc.org/CCJPodcasts/060309Beastall.mp3

Transcript: http://www.aacc.org/events/podcast/Documents/060309Beastall.pdf