Sunday, 26 February 2012

Is Vitamin D deficiency the Scurvy of our time?

We're hearing a lot about vitamin D deficiency these days.

Nutritional research is rarely a topic of much interest for the big pharmaceutical companies, but finally there is some research being done that would suggest that vitamin D is a much more important molecule than previously suspected.  A definite association with osteomalacia and rickets, and possibly linked to depression, diabetes, multiple sclerosis and other illnesses, vitamin D research is finally getting the attention it deserves, but at this stage it seems that we are a long way from really understanding what the full effect of vitamin D deficiency is.

Vitamin D is a substance usually made in the skin from the UV light, but there are also dietary sources too, such as eggs and fish, making it quite unlike all the other vitamins.

Unfortunately, this mixture of sources is also affecting scientific research, preventing many studies from having true 'control' groups.
But the biggest problem of all is the lack of consistency when it comes to measuring vitamin D levels in the different laboratories..and we're not talking about the difference between countries.  Unfortunately, even in Australia, there are numerous ways of measuring vitamin D levels from one lab to another. 

 This makes it virtually impossible to compare data or entertain the thought of doing a meta-analysis (where data is pooled from a variety of studies around the world).  And for patients having treatment for Vit D deficiency..let's hope they're not changing labs for their next blood test or the result will be meaningless.
Hard to believe that in this modern age, a lack of consistent analysis and an inability to therefore share information is preventing us from learning about one of the most important vitamins known to mankind.

One hundred years ago, the term 'vitamin' was first coinied by Casimer Funk at the Lister Institute in London.  Vitamins are micronutrients essential for normal cellular function.  They generally fall into 2 groups..the fat soluble (A, D, E and K) and the water soluble (Bgroup, C).  With the exception of vitamin B12, only the fat soluble vitamins can be stored in the body.
Scurvy, due to a severe deficiency of Vitamin C (also known as ascorbic acid), was a common disease affecting the sea-farers of the 16th-19th centuries.  It took more than 300 years for the cure of scurvy to be identified, and even longer for the ultimate cause to be identified (ascorbic acid wasn't isolated until 1932).  In the meantime, countless naval tragedies claimed the lives of millions of men, either directly or indirectly as a consequence of vitamin C deficiency.  Scurvy killed more people than all the storms, shipwrecks, combat and other diseases combined.  Lemon juice rations were used as a means of scurvy prevention by the British during the blockade of Napoleonic France, and thanks to the resultant unusually healthy navy, the British rapidly became the first truly global superpower, able to send large numbers of people to the Antipodes on searoutes that took many months to complete.

How sad then, to discover that the cure for scurvy was actually documented in the early 17th century by a English naval merchant who had grown up in Portugal, recognising the value of lemon juice and going to great lengths to ensure that he always carried it on journeys to the East Indies.  Somehow, this cure was overlooked within 30yrs of its discovery, (perhaps partly because lemon juice was expensive!) and it took another 260years before official instructions re lime juice were issued by the British.

Scurvy is still around today, for it cannot be vaccinated against.  The early signs being that of lethargy and mental more advanced cases dental loss, swollen gums and poor wound healing.  Wherever there is a war, a drought, a famine, a flood, (anything that interferes with normal transport and food distribution networks), the elderly and infirm, or those with imbalanced diets, you can be sure to find scurvy.

The prevalence and incidence of vitamin D deficiency, on the other hand, can only be estimated currently, but it is very likely to be of a much greater magnitude than that of vitamin C deficiency,given our modern lifestyle of working long hours indoors with deliberate avoidance of excessive sun exposure, especially in those trying to limit the cosmetic and medical consequences of a life spent too much in the sun, as our parents often did from the 1950s through to the 1980s.

Let's hope that scientists and governments around the world remember the millions who died unnecessarily from scurvy, and unite in the near future to share data on vitamin D from a universal research method.  For everyone else, please remember that a varied diet, rich in fruit and vegetables, is one of the most important health measures you can do on a daily basis..especially in those over 40!

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