At 1:32 PM -0600 11/7/11, Ben Liberman wrote:
>... an article about the relationship between vitamins D and K which claims that "current research points to the central role of vitamins D and K to ensure optimal calcification of bones while preventing pathologic calcification of arteries".
>
>Brittle Bones and Hardened Arteries: The Hidden Link
>By Julius Goepp, MD
>http://www.lef.org/magazine/mag2010/sep2010_Brittle-Bones-Hardened-Arteries_01.htm
>
>There are some very interesting citations in there about the results of studies on high dose K2 and reversal of osteoporosis while simultaneously reversing calcification of other tissues in the body.

K2 WARNING: many blood thinners work by interfering with Vitamin K.  READ UP ON THIS BEFORE MESSING AROUND.

Here is the standard vitamin K warning:

"Do not take this product if you are taking "blood thinners" such as Coumadin®. If you are under a physician's care or taking medication, if you are pregnant or nursing, or if you are taking oral contraceptives, consult your healthcare professional before using this product."


As for the rest of us, most supplements measure K2 in micrograms.  I recently found a 15mg K2 from Vitamin Research Products.

sources:

http://www.vrp.com/bone-and-joint/ultra-k2

http://www.lef.org/Vitamins-Supplements/Item30487/Ultra-K2-Menatetrenone.html?source=search&key=ultra%20k2

As far as I know, for people who do not have a specific problem with vitamin K supplementation, the wikipedia entry looks very good.

Here is the tox info from there:

"Although allergic reaction from supplementation is possible, there is no known toxicity associated with high doses of the phylloquinone (vitamin K1) or menaquinone (vitamin K2) forms of vitamin K and therefore no tolerable upper intake level (UL) has been set.[citation needed]

Blood clotting (coagulation) studies in humans using 45 mg per day of vitamin K2 (as MK4)[26] and even up to 135 mg/day (45 mg three times daily) of K2 (as MK4),[50] showed no increase in blood clot risk. Even doses in rats as high as 250 mg/kg body weight did not alter the tendency for blood-clot formation to occur.[51]

However, a synthetic form of vitamin K, vitamin K3 (menadione), is demonstrably toxic. In fact, the FDA has banned this synthetic form of the vitamin from over-the-counter supplements because large doses have been shown to cause allergic reactions, hemolytic anemia, and cytotoxicity in liver cells.[1]"