John,
I have seen this website before but I certainly don't agree with it.
I have also emailed Dr John Cannell MD of the Vitamin D Council for his opinion.

It is established that only SOME forms of Vitamin D are indeed a steroid hormone rather than a Vitamin, but we should bear in mind the following before advising anyone to supp-le-ment with it or not.........................

Cholecalciferol (vitamin D3) is the naturally occurring form of vitamin D. Cholecalciferol is made in large quantities in the skin when sunlight strikes your bare skin. It can also be taken as a supplement.

Calcidiol (25(OH)D3 or 25D3) is a "PREHORMONE" in your blood that is directly made from cholecalciferol. When being tested for vitamin D deficiency, calcidiol is the only blood test that should be drawn. When someone refers to vitamin D blood levels, they are referring to calcidiol levels. Your doctor can order calcidiol levels but the lab will know calcidiol as 25-hydroxyvitamin D.

Calcitriol (1,25(OH)2D3 or 1,25D3) is made from calcidiol in both the kidneys and in other tissues and is the most potent "STEROID HORMONE" derived from cholecalciferol. Calcitriol has powerful anti-cancer properties. It is sometimes referred to as the active form of vitamin D. Calcitriol levels should never be used to determine if you are deficient in vitamin D.

Studies show that if you go out in the summer sun in your bathing suit until your skin just begins to turn pink, you make between 10,000 and 50,000 units of cholecalciferol in your skin. Professor Michael Holick of Boston University School of Medicine has studied this extensively and believes a reasonable average of all the studies is 20,000 units. That means a few minutes in the summer sun produces 100 times more vitamin D than the government says you need! This is the single most important fact about vitamin D.

The skin does another amazing thing with cholecalciferol. It prevents vitamin D toxicity. Once you make about 20,000 units, the same ultraviolet light that created cholecalciferol begins to degrade it. The more you make, the more destroyed. So a steady state is reached that prevents the skin from making too much cholecalciferol. This is why no one has ever been reported to develop vitamin D toxicity from the sun, although (admittedly) it is possible when taking vitamin D orally.
Toxicity can occur at mounts of 50,000ius per day via supplementation over several months, but then no one is advising or advocating supplementation at that level.

In the absence of sunlight or sufficient sunlight-exposure on the skin, (which I think includes the majority of people) especially in the Winter, the only way to obtain sufficient levels of this Vitamin is via supplementation.
If your intake of Vitamin D3 is approx 20,000ius per day (from all sources) than you are receiving what the body has determined to be the optimum amount.

Regarding the question of VDR's being blocked so that Vitamin D becomes poisonous or harmful to the body is complete nonsense, and all the experts that I know of agree with this analogy, and they include Professor Michael Holick and Professor Cedric Garland who are both experts on Vitamin D.

It is also irresponsible to advise anyone from supplementation of this Vitamin, and in responsible and healthful amounts, and especially in the absence of sunlight exposure to the body for the vast majority, which will in turn prevent many serious and potential/actual
chronic/terminal diseases........
as just ONE example.................
http://www.naturalnews.com/028357_vitamin_D_deficiency.html


BTW. If VDR's are blocked then Rickets would be a more widespread health-problem than it already is, but this disease is apparently re-emerging because of "deficiency" and for no other reason.

Chrisb1.