Sunday, 25 April 2010

BBC Radio 4: Case Notes on Vitamin D

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1 comment:

  1. Circulating 25-Hydroxyvitamin D Levels in Fully Breastfed Infants on Oral Vitamin D Supplementation"
    The full text of this paper is online.
    It shows at latitude 32N it takes 6400iu/daily/D3 to raise 25(OH)D to around 60ng/ml at which level babies can grow with optimum bone mineral density.
    It is frankly ridiculous to think that taking the amounts of vitamin D recommended in this edition of Case Notes will do anything other than leave people Vitamin D deficient.
    Given regular full body sun exposure humans naturally attain and maintain 25(OH)D levels between 60~80ng/ml or 150~200nmol/l
    Human skin will generate 10,000~20,000iu/daily / D3 if cholesterol levels in the skin are high and 25(OH)D levels are low. As our cholesterol levels drop (natural aging or statin use) so our ability to make D3 declines. We also make less vitamin D as our body stores D3 and has met it's daily requirement. You cannot overdose on Vitamin D3 from sun exposure as unabsorbed D3 is processed on into supra sterols the body doesn't use.
    The safe upper limit for vitamin D is 10,000iu daily but this allows for a huge margin of safety as prolonged use of 40,000iu/daily would be required to raise status above the 200ng/ml 500nmol/l at which adverse events have been recorded.
    The program referred to 75nmol/l as being adequate however that is simply not true.
    It may be the case that the average Caucasian can achieve reasonable Bone Mineral Density at that level but that still leaves many people who require more. Over 110nmol/l 44ng/ml is required to guarantee every Caucasian has the ability to absorb and control maximum amounts of calcium from the diet.
    The Vitamin D requirement in health and disease
    Robert P. Heaney

    We also have to appreciate that at 40ng/ml 100nmol/l humans only have sufficient vitamin D to meet immediate daily needs. We have no stored reserves of D3. Our stores of D3 only begin to grow after we have met our daily needs in full.
    Having a stored reserve of D3 in muscle and fat tissue means our ability to produce the active hormone Calcitriol is never compromised and this is reflected in a lower incidence of chronic illness found in those who maintain 25(OH)D levels above 55ng/ml 137.5nmol/l
    Generally speaking it takes 1000iu/daily/D3 per 25lbs weight to achieve a 25(OH)D around 60ng/ml. After 3months use of an effective strength D3 supplement A postal 25(OH)D test will show if that is sufficient for you a further 1000iu/daily for each 10ng/ml extra rise needed may be required.
    Using oil-based D3 gel caps is the most effective form. I suggest those based on Medium Chain Triglyceride oil will be best absorbed and metabolized. Taking Vitamin D with the largest meal of the day also improves absorption.

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