Vitamin K, Osteocalcin and Bone Health: Looking In and Beyond the Literature

13. August 2009 by Kara Fitzgerald, ND 7 Comments

Looking in and beyond the Literature

I love batting new research around the Institute (and beyond). It’s very satisfying to get expert opinions far and wide on topics that are not only interesting, but timely and important to our health.

Also: it’s VERY important to read the literature closely, and ask questions about study design before digesting in full the conclusions drawn.

A great resource for synthesis emails of recent literature abstracts and commentary pertinent to functional medicine is from Emerson Ecologics. You can find them at www.emersonecologics.com.

Recently, Steve Austin, ND, commented in Emerson on Minkley N, Harke J, Krueger D, et al. Vitamin K treatment reduces undercarboxylated osteocalcin but does not alter bone turnover, density, or geometry in healthy postmenopausal North American women. J Bone Mineral Res 2009;24:983-91. (You can sign up for the Emerson Email, or grab the abstract at PubMed)

His commentary generated much Metametrix Institute commentary. Follow the conversation in the comments below:

Kara Fitzgerald

8/13/2009 10:17:14 AM #

Hey gang,

The vitamin k trial showed no improvement as compared to controls ( both groups were post menopausal, non-osteoporotic women), although with vitamin K1 and K2 supplementation, undercarboxylated osteocalcin (ucOC) ( www.metametrix.com/.../VitaminK ) decreased.

It seems to me that if we understand that osteocalcin works by ushering calcium to bone, perhaps this trial failed because the study group took insufficient calcium and vitamin D. So, you can have lots of fabulously carboxylated osteocalcin, but if you don’t have enough calcium to usher to the bone, then take tons of K, and still no efficacy.

Nutrients don’t work in a vacuum.

Perhaps what we can tentatively conclude from this study is that one requires more than 200IU D and 313mg calcium for bone heath along with vitamin K. And that K1 and K2 appear equally efficacious as carboxylating osteocalcin.

Richard Lord

8/13/2009 10:19:52 AM #

Here’s a little further mechanistic background for this discussion:
Bones grow because they are used, not just because some calcium (and phosphorus and magnesium and a few other things) is available. Vitamin K guides of chauffeurs calcium, but it responds to electrostatic fields generated when bones are under stress. No stress (exercise) > no fields > no calcium chauffeured to sites of nucleation.

Also, in addition to the multiple positive bone fracture outcome studies described by Steve Austin, let’s keep our eyes out for cardiovascular disease prevention outcomes in vitamin K interventions. That’s because osteocalcin can help to prevent soft tissue calcification via its chauffeuring of calcium, keeping Ca++ bound up snugly until they find a proper place to sit.

8/13/2009 10:21:39 AM #

That said, since the carboxylation process entails securing some calcium, would the improvement in osteocalcin imply that calcium being ushered to bone is also present in increased amounts, or could one have under-calcified osteocalcin? Richard?

By the way- seems that osteocalcin improves insulin sensitivity as well. Amazing. And another reason to test for it, as well as take vitamin K…

8/13/2009 10:23:06 AM #

Kara has a good question regarding the saturation of OC with Ca++ at any given degree of gamma carboxylation. I have never seen reports of such measurements. They could easily be done in vitro.

The line of thought takes us to a picture of the central phenomenon of calcium regulation. I can imagine that the overall effect of OC carboxylation is to raise the level of available Ca++ in a way that does not disrupt the myriad calcium regulatory systems. So, in the presence of adequate vitamin K, the OC carboxylation and decarboxylations reactions must be able to respond to ionic calcium needs which is the factor driving the whole system of calcium regulation.

Ca++ ↓ > greater degree of OC carboxylation (if vitamin K is not limiting)
Ca++ ↑ > less degree of OC carboxylation

Looking at it this way lets us see the central importance of vitamin K that goes far beyond just preventing osteoporosis.

Keith McCormic

8/13/2009 10:51:46 AM #

I'm not surprised about the no increase in BMD with the vit K...as you say...nutrients don't work in a vacuum. It's just like seeing studies that don't show increased bone density with calcium. K is good and important but only part of the web. ...AND...if there is a lot of chronic inflammation spewing out RANKL producing T cells, the K won't have an effect. Also, the women studied didn't have osteoporosis. So, why would anyone expect an increase in BMD...if the systems not broke to begin with, then adding one ingredient won't fix something that's not broken. Hope you are well.

Terry Pollock

8/13/2009 10:53:32 AM #

Several studies I found while researching my osteoporosis talk in April revealed that K2 did not increase apparent BMD.

In one study, hydroxyapatite crystals prematurely nucleated because of Mg deficiency, supposedly. Then, in those subjects, adding K2 normalized the nucleation time, with no added Mg. How K works in total bone health seems a bit squirrelly.

Tina Kaczor, ND, FABNO

9/16/2009 7:02:56 PM #

Kara and company,

Hey Kara! I think reading the article on osteoporosis and vitamin K I just wrote for the Natural Medicine Journal might be interesting for y'all. It appears that while BMD improvements are not always found, a reduced fracture risk is more strongly correlated with K intake/intervention... one explanation is that bone geometry, not density, is improved resulting in better bone strength and less fractures. This is not my theory, it is cited in my article ... you can check it out at www.naturalmedicinejournal.com

Oh, I saw this blog when I was looking for the osteocalcin test at Metametrix... okay, now I have to go find it somewhere on your site.

Tina Kaczor, ND, FABNO
Senior Medical Editor, Natural Medicine Journal