Saturday, August 21, 2010

So if vitamin D is so important what is the history behind it?

As this is a long and intricate subject, I will split the blog into two parts, trying to include enough information to make the reading interesting, but leaving out most of the highly technical information. In part two, I will also include more of the questions vs answers debate in vitamin D.

In a nutshell, Vitamin D is actually a “pre-steroid hormone” not a vitamin. It was discovered around the same time as other “vital Amines and was allocated the letter D – and so it came to be known by this accepted title. Unfortunately, this historical accident left everyone believing it was nothing more than a fat soluble vitamin.

The first scientific description of a vitamin D-deficiency, namely rickets, was provided in the 17th century by both Dr. Daniel Whistler (1645) and Professor Francis Glisson (1650). The major breakthrough in understanding the causative factors of rickets was the development in the period 1910 - 1930 of nutrition as an experimental science and the appreciation of the existence of vitamins. It was not until the 1930’s that vitamin D2 and vitamin D3 structures were chemically characterised. The elusive antirachitic (anti-rickets) component of cod liver oil was shown to be identical to the newly characterised vitamin D3. These results clearly established that the antirachitic substance vitamin D was chemically a steroid, or more specifically, a secosteroid. (A `secosteroid` is a molecule similar to a steroid but with a `broken` ring. Secosteroids are very similar in structure to steroids except that two of the B-ring carbon atoms (C9 and 10) of the typical four steroid rings are not joined, whereas in steroids they are. In humans, the most important secosteroid is Vitamin D).

Vitamin D is a fascinating molecule with a fascinating story. Historically, “vitamins” were defined as chemicals that humans required from their environment that were “vital” to human health. These chemicals were needed only in very small amounts to prevent disease; an absence of a particular vitamin in the diet led to a specific deficiency disease: vitamin C, scurvy; thiamine, beri beri. Other vitamin deficiencies were found to be a bit more complicated: vitamin B12 deficiency was found to cause a type of anemia, dementia, and spinal cord problems. Of course more modern research proves conclusively that vitamin D3 is also plays a major role in these diseases as well. Because vitamins are required in such small amounts, and are often present in small amounts in foods, their discovery was an opportunity to prevent and cure several diseases.

Heart disease is one of our three biggest killers (along with cancer and stroke). One of the better prospective studies done on vitamin D and heart disease followed subjects over time, measuring vitamin D levels and following them to see who developed a first incidence of heart attack. They found that those with low vitamin D levels who also had high blood pressure (a well-recognized risk factor for heart disease) were more likely to develop a first heart attack than hypertensive patients with higher vitamin D levels.

It is nearly impossible to ingest sufficient vitamin D in a typical diet, and it is nearly absent from breast milk. In areas where sunlight is scarce or where culture prevents sun exposure, rickets was more common. Rickets became rare in the U.S. once children’s parents began shoving them full of cod-liver oil, and once vitamin D was added to milk.

So make sure you get your dose of vitamin D - on your local, professional megaSun sunbed!!!