Re: A hypothesis on UC/PSC/ --Vit D and A

September 9, 2007

RE: Vit D and A

Vit D must be measured as Vit D-25. If the doctor isn't sure and

orders just Vit D you might get just a Vit d2 or d3 which doesn't

reflect the important metabolite level. I mention this only because

the the levels quoted don't sound like the normal units for D-35 in

ng/ml. See the Vit D file in the files or below.

Vit A supplimentation is much more likely to cause toxicity than Vit

D so there should be some caution in supplimenting A. Vit A can be

toxic to the liver. Here is a guideline:

Intake of up to twice the RDA of vitamin A of 5000 IU is thought to

be safe. However, an intake of preformed vitamin A (retinol) in the

range of 10,000 IU per day or higher — which might be attainable from

foods rich in vitamin A (especially liver, fortified breakfast

cereals, and dairy products) in combination with a multivitamin

containing the RDA of retinol — might be undesirable. Intakes of

preformed vitamin A in this range have been associated with an

increased risk of hip fracture,25 and daily intakes of approximately

10,000 IU during pregnancy have been associated with specific birth

defects,26 but confirmation of these associations is needed.

VIT D levels

Although there is no consensus on optimal levels of 25-hydroxyvitamin

D as measured in serum, vitamin D deficiency is defined by most

experts as a 25-hydroxyvitamin D level of less than 20 ng per

milliliter (50 nmol per liter).7,8,9,10 25-Hydroxyvitamin D levels

are inversely associated with parathyroid hormone levels until the

former reach 30 to 40 ng per milliliter (75 to 100 nmol per liter),

at which point parathyroid hormone levels begin to level off (at

their nadir).10,11,12 Furthermore, intestinal calcium transport

increased by 45 to 65% in women when 25-hydroxyvitamin D levels were

increased from an average of 20 to 32 ng per milliliter (50 to 80

nmol per liter).13 Given such data, a level of 25-hydroxyvitamin D of

21 to 29 ng per milliliter (52 to 72 nmol per liter) can be

considered to indicate a relative insufficiency of vitamin D, and a

level of 30 ng per milliliter or greater can be considered to

indicate sufficient vitamin D.14 Vitamin D intoxication is observed

when serum levels of 25-hydroxyvitamin D are greater than 150 ng per

milliliter (374 nmol per liter).

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