This doc I created shows my three faves compared SBS. Strains are highlighted to show which ones are not in the other formulas.
If Quest did your test - and they do more D testing than anyone else, know that there are major problems with their test - generally causing them to run about 1/3 too high. .....though not always - sometimes they're low. More on that after the following questions.
at what latitude do you live?
how much midday, full body, unprotected summer exposure do you get?
how much 'incidental' 'out and about' type expousre?
do you wear s/s? hats? long sleeves?
Quest and Vitamin D
Accuracy and precision issues abound due to the complexity of Quest's testing method, the poorly trained lab techs, lack of oversight of the techs and too many tests to run. The complexity of the test alone isn't a problem but combined with the latter factors, it's a recipe for disaster: and it has been exactly that. Another MAJOR player is that it doesn't appear that Quest has normed their test to the gold standard (dia sorin) which is used in all of the D studies. This is huge and Quest isn't talking. Unless it's normed, the result is truly meaningless. Read more here:
John Cannell's excellent 7/2008 Newsletter - read all of it
NYT article - even though they mucked up some of the key info, it's still very good.
Vitamin D Council Quest / Labcorp Testing Project
If you've used Quest, divide your result by 1.3 to obtain a result that is likely to be more accurate AND consider retesting via LabCorp or ZRT just to be 'sure'. I prefer ZRT...details below.
If you've used LabCorp or ZRT, double check your number. What exactly is it? The middle of the reference range is 60-65 ng/mL. Since D toxicity has NEVER been documented at a 25(OH)D level below 200 ng/mL, and since there are documeted cases of serum D reaching 100 ng/mL from sun exposure alone (in lifeguards in Miami), it would seem reasonable, if indeed your levels are already at 60-65 ng/mL, to try to bring them up to the 80ish range - or possibly even 100 ng/mL though the latter I would do only with sun or sun/supplements in combo - not with sun alone.
The ZRT test (home finger stick test) can be ordered from three different outfits. Here they are in order of my preference:
D*Action study via Grassroots Health - the requirement is 2x/year for 5 years. Please consider joining the study.
The Vitamin D Council - worthy of *all* of our support. ZRT donates $10 to them everytime a test is purchased through the D council's website. But please, join the Grassroots Health study and just donate the $10 to the D Council directly.
ZRT sells the test directly
And why is ZRT's test okay when it's LC-MS/MS like Quest's test?
If it's in the budget, please join the study. Be a part of something that will change the face of public health all over the world. Support the The Vitamin D Council, if you can, for the very same reasons. What Carole (of the grassroots health) and John Cannell (D Council) are both doing is - amazing. unparallelled. superhuman. They are changing lives, many many lives, through the extensive and growing reach of their organizations.
I wrote this document on vitamin D and am including the full text here:
Vitamin D Dosing and Levels
nmoL - units used to measure D most places in the world
ng/mL - units used in the US
** Please be sure to pay attention to the units given on your lab report.
** Quest Labs -problems remain: at this point in time, it still appears that 25(OH)D
results from Quest need to be divided by 1.3. to obtain results normed to the gold standard.
See vitamindcouncil.org, grassrootshealth.net for further information.
What should my vitamin D level be?
see below for information on various vitamin D levels........
❍ 32 ng/mL (80 nmoL) is the bottom of the current reference range. Still
leaves us in a state of substrate starvation which isn't good. And if Quest** did
your test - see note above - you need to divide by 1.3
❍ 40 ng/mL (100 nmoL) the minimum recommended by currently by
any major D researcher (see grassrootshealth.net).
❍ 50 ng/mL (125 nmoL) is the point at which we have sufficient substrate
for managing calcium levels and have additional to use for other necessary
physiological functions - including gene expression (300+ other functions in our bodies)
❍ 60-65 ng/mL (150-162.5 nmoL) is reasonable number for which to aim.
It's the 'middle of the current reference range for the major US labs. European
and canadian labs are behind the times on this one and are still generally using
a much lower range.
❍ 80 ng/mL (200 nmoL) is a target number for some researchers and is still
within the range of a physiological range of what we could achieve from sun -
ie a physiologically appropriate level.
❍ 100 ng/mL (250 nmoL) is a typical serum level of 25(OH)D obtained by lifeguards,
in South Florida, from sun only, implying that this is a very physiologically normal -
possibly optimal? - number for which to aim.
❍ 200 ng/mL (500 nmoL) is the lowest blood level of 25(OH)D at which there
has been documented D toxicity. There has never been a case reported at levels
lower than that.
☑ 1000 IU (25 mcg) per 25 lbs body weight per day is a very reasonable dose of
D3 for someone who
→ works indoors midday
→ wears clothes midday
→ avoids sun midday
→ wears any sunscreen midday
☑ 10,000 IU-50,000 IU vitamin D3 is produced in the skin upon full body exposure
to sunlight......with the average of the studies being about 20,000 IU. However,
do not take more than 1000 IU per 25 lbs body weight per day without periodic
testing of 25(OH)D levels. Just because it's physiologically normal to PRODUCE
10,000-50,000 IU in the skin, doesn't mean it's physiologically normal to TAKE
that much orally. Test a couple of times per year. And maybe double that the first
couple of years.
☑ Don't be afraid to take as much D3 as is required to raise your serum 25(OH)D to
50-100 ng/mL (125-250 nmoL) There is a 25-50% variation in serum
vitamin d levels at 'x' amount of supplementation rate due to genetic variations
in vitamin d binding protein.
☑ Early AM and later afternoon sun exposure on face, hands and arms is not sufficient
to raise vitamin D levels or maintain optimal vitamin D levels.
☑ Fall, Winter and Spring sun exposure is not generally sufficient to raise viamin D levels
or to maintain optimal D levels.
☑ A tan does not necessarily indicate sufficient vitamin D levels. It's easy to tan from UVA
without getting sufficient UVB to raise D levels.
☑ A person (tan or not) who's been getting
→on most body skin
to the point just before a burn occurs, may have optimal D levels during the summer.
☑ The Vitamin D Council (vitamindcouncil.org) has all of the D research, reference cites
and links to peer reviewed journal articles that you'd ever want to read, plus several
☑ Grassrootshealth.org has a tremendous amount of good information as well.
☑ Stanford and other major D research centers have podcasts in iTunes that are excellent resources.