Vitamin D3

[Kaes]

all,
how strongly do you feel about Vitamin D/D3 as a daily supp?
and, what have you found--or what do you know--to be its benefits?
thanks
kaes

 

[Vince Carter]

I take it, 5000iu in the morning though I have no tangible feeling from it but I take A LOT of supps and vitamins so it's hard to tell. Its one thing I always forget to test for.

 

[CoastWatcher]

I take 4000 IU ever day. My levels were appallingly bad when I started TRT, living in a cold-weather, low-sun country certainly doesn't help me in that regard. Now that I am in the upper quartile on my lab's reference range I feel...no different. But I don't "feel" HCG either and am dedicated to it. There is enough evidence to support the use of Vitamin D. So, I'm in.

 

[Kaes]

i feel like i read somewhere that some consider vitamin D to be a hormone, which i found strange, but interesting.
yeah...here it is. i had no clue.

We've been taught that Vitamin D is the “bone vitamin”, but it is really a sun hormone. It is not in the food. It is a chemical that we make on our skin from sun exposure. Only the UVB wavelength of light makes vitamin D. It is a hormone like thyroid, estrogen or testosterone.

 

[CoastWatcher]

i feel like i read somewhere that some consider vitamin D to be a hormone, which i found strange, but interesting.
yeah...here it is. i had no clue.

We've been taught that Vitamin D is the “bone vitamin”, but it is really a sun hormone. It is not in the food. It is a chemical that we make on our skin from sun exposure. Only the UVB wavelength of light makes vitamin D. It is a hormone like thyroid, estrogen or testosterone.

it is a "secosteroid" (https://en.m.wikipedia.org/wiki/Secosteroid).

 

[Fireproof]

Check out all these benefits:
https://examine.com/supplements/Vitamin+D/

I'm a believer. I taker 5,000 IU daily and have been for a while.

 

[Vince]

I take 6000iu of D3 daily. http://www.vitamindcouncil.org/about-vitamin-d/

 

[Re-Ride]

25-hydroxycholecalciferol serum assay aka "25(OH)D" aka "25-hydroxy-D" coupled with knowledge of how effectively one personally processes cholcalciferol is all anyone needs to know when deciding on D3 supplementation. Not how much Joe or Guinevere had for lunch.

Once you know your baseline AND have identified a serum goal you can then, sort of, guestimate daily intake required to achieve that goal. Not everyone achieves the same serum level from the the same dosing. The only way to verify that you are moving in to a safer zone is with frequent serum testing.

There is an association of serum in the "safer zones" with: i) improved survival ii) fewer clinical manifestations of certain serious maladies. The association is strongly suggestive of but does not prove that higher OH-D-25 levels directly result in these clinical outcomes. Higher serum folks could be more vigilant in other areas of health or maybe they laugh more.

Test results in the U.S. are typically expressed in ng/ml. Elsewhere it's nmol/l.

The optimum OH-D-25 level is 45, 60, 75 or more depending on who you want to believe. The Vit D Council and the Endocrine Society both claim 40-50. One Canadian government site says 75.

As an example, I could not, after two years, get out of the single digits on 50k IU ergocalciferol (D2), the Rx synthetic D that Big Pharma likes to push. No amount of strong sun exposure made any difference either. 5k IU D3, then 10, then 15 then 20,000 per day and I gradually climbed to mid 40's. Raising OH-D-25 can be a long process taking a year or more. Most folks will do much better. But relying on averages is a poor approach as seen here.

 

[MikeXL]

What is the significance of it being a secosteroid?

 

[CoastWatcher]

What is the significance of it being a secosteroid?

I've attached a very good discussion of the hormone/vitamin distinction that prompted our speculation.

What is Vitamin D?: Untangling the Confusions
Although some carelessly worded studies and official nutrition committee reports in both the US and Europe casually claim that Vitamin D is more of a hormone than a nutrient, this is in error and regrettably an all too common misconception, and stems from failure to differentiate the nature and function of various Vitamin D-related compounds like ergocalciferol, cholecalciferol, 1,25-dihydroxyvitamin D, 25-hydroxy-VitaminD, and the shorthand terms calcitriol and calcidiol (distinguished below).
The preeminent Vitamin D researcher and expert Ronald Vieth, one of the "fathers" of modern Vitamin D theory, at the University of Toronto, critically shed light on these issues in his now landmark paper "Why "Vitamin D" is Not a Hormone"[SUP]1[/SUP], and I have extended and adopted his distinctions below for the sake of accessibility and clarity. However definite his analysis is, I will nonetheless before closing this discussion introduce one non-trivial point of disagreement that I think deserves mention as a compromise perspective that more fully and clinically realistically captures the current sense of Vitamin D..
The Facts
First we have Vitamin D which is referent to either Vitamin D3 (cholecalciferol) or Vitamin D2 (ergocalciferol). Vitamin D is the structural raw material that one or more hormones or prehormones (not prohormones) are made from, and meets the strict definition of a vitamin, namely an organic substance present in minute amounts in the natural diet (foodstuffs, not supplements) that is essential to normal metabolism, and insufficient amounts of which in the diet may cause deficiency diseases. Vitamin D itself (whether D3 or D2) is not a hormone which is strictly defined as a substance formed in one organ but transported in the blood to another organ and capable of altering the functional activity of that target organ[SUP]1[/SUP]. In addition, the set of compounds derived from the cholecalciferol (Vitamin D3) molecule are known as secosteroids.
The Vitamin D process involves roughly that:
(1) the liver readily hydroxylates vitamin D – using cytochrome P450 enzymes –in to 25(OH)D, the primary circulating form of vitamin D,
(2) then the kidney further hydroxylates 25(OH)D into the active form 1,25-dihydroxyvitamin D which is also referred to as 1,25(OH)2D, which then acts to maintain serum calcium through sequential direct effects on calcium absorption and excretion, and through a complex series of inter-relationships with serum phosphate and parathyroid hormone.
But there are two hormonally-active substances, known as (fat-soluble) secosteroids, derived - and distinct - from Vitamin D (either D2 or D3), these being:
(1) 1,25-dihydroxyvitamin D (calcitriol) which is a calcium-regulating hormone, an adaptive hormone produced in response to calcium deficiency, it functions the same way as other steroid hormones, namely by interacting with its cognate vitamin D receptor (VDR);
(2) 25-hydroxy-VitaminD which is a prehormone (not a prohormone), a glandular secretory product, having minimal or no inherent biologic potency, that is converted peripherally to an active hormone.
However, 1,25-dihydroxyvitamin D (calcitriol) which is the metabolic product of vitamin D, is itself a potent, pleiotropic repair and maintenance secosteroid hormone acting as a a molecular switch targeting over two hundred known human genes across a wide variety of tissues[SUP]2[/SUP], and functions as an adaptive hormone (being produced in response to calcium deficiency).
The actions of 1,25-dihydroxyvitamin D (calcitriol) are mediated by the Vitamin D receptor (VDR), a ligand-activated transcription factor that functions to control gene expression, 1,25-dihydroxyvitamin D (calcitriol) thus serving as a transcriptional regulator of various genes[SUP]2[/SUP]. Indeed, recent data shows that 1,25-dihydroxyvitamin D (aka, 1,25(OH)2D)-activated VDR modulates the expression of genes at both single gene loci and also at the level of gene networks[SUP]3,4,5[/SUP].
Given, as I have demonstrated above, that:
(1) Vitamin D is a vitamin, with
(2) 25-hydroxy-VitaminD being a prehormone (a glandular secretory product converted peripherally to an active hormone, namely 1,25-dihydroxyvitamin D (calcitriol); while
(3) 1,25-dihydroxyvitamin D (calcitriol) is a secosteroid hormone functioning as a a molecular switch which is known to target over two hundred known human genes, and thus serves as a transcriptional gene regulator,
then I would argue that we need to construe Vitamin D itself as something more than a vitamin but less than a strict hormone (that function being reserved for 1,25-dihydroxyvitamin D (calcitriol)), in order to reflect and accommodate its gene transcriptional regulator functions, and so it would be more clarifying to speak of Vitamin D as not a simple vitamin, but rather as a biomodulator vitamin, a vitamin which exerts transcriptional regulation of genes at the molecular pathway level.
Summary
- Vitamin D itself - neither cholecalciferol (Vitamin D3) nor ergocalciferol (Vitamin D2) - is not a hormone, but rather a biomodulator vitamin (capable of gene regulation);
- the primary active form 1,25-dihydroxyvitamin D (calcitriol) is a calcium-regulating hormone;
- the primary circulating non-active form 25-hydroxy-VitaminD is a prehormone, converted peripherally to the active hormone 1,25-dihydroxyvitamin D (calcitriol).
References
Vieth R. Why "Vitamin D" is not a hormone, and not a synonym for 1,25-dihydroxy-vitamin D, its analogs or deltanoids. J Steroid Biochem Mol Biol 2004; 89-90(1-5):571-3.
Cannell JJ, Hollis BW, Zasloff M, Heaney RP. Diagnosis and treatment of vitamin D deficiency. Expert Opin Pharmacother 2008; 9(1):107-18.
Pike JW, Meyer MB. The vitamin D receptor: new paradigms for the regulation of gene expression by 1,25-dihydroxyvitamin D(3). Endocrinol Metab Clin North Am 2010; 39(2):255-69.
Pike JW, Meyer MB, Martowicz ML, et al. Emerging regulatory paradigms for control of gene expression by 1,25-dihydroxyvitamin D3. J Steroid Biochem Mol Biol 2010; 121(1-2):130-5.
Sutton AL, MacDonald PN. Vitamin D: more than a "bone-a-fide" hormone. Mol Endocrinol 2003; 17(5):777-91.
Sep 1, 2014

 

[Braun]

Very good information here posted by other members so I guess there's no reason in me adding anything new. All I want to say is that I take Vitamin D3 for a while and either it is placebo effect or no, but I kinda feel better on it.