by itself exerts significant bone density/strength increasing properties in dozens of studies, when combined with other bone health-promoting agents (e.g., vitamin D3, prescription drugs like Fosamax and calcitonin), an exaggerated synergy of bone health-promoting effects develop.
--The MK-4 form of vitamin K2 is short-lived, lasting only 3-4 hours in the body. The MK-7 form, in contrast, the form in natto, lasts several days. MK-7 and MK-8-10 are extremely well absorbed, virtually complete.
--Bone health benefits have been shown for both the MK-7 and MK-4 forms.
--Coumadin (warfarin) blocks all forms of vitamin K.

Interestingly, farm-raised meats and eggs do not differ from factory farm-raised foods in K2 content. (But please do not regard this as an endorsement of factory farm foods.)
Another interesting fact: Since mammals synthesize a small quantity of Vit K2 forms from vitamin K1, then eating lots of green vegetables should provide substrate for some quantity of K2 conversion. However, work by Schurgers et al have shown that K1 absorption is poor, no more than 10%, but increases significantly when vegetables are eaten in the presence of oils. (Thus arguing that oils are meant to be part of the human diet. Does your olive oil or oil-based salad dressing represent fulfillment of some subconscious biologic imperative?)
If we believe the data of the Rotterdam Heart Study, then a threshold of 32.7 micrograms of K2 from cheese yields the reduction in cardiovascular events and aortic calcification.
It's all very, very interesting. My prediction is that abnormal (pathologic) calcium deposition will prove to be a basic process that parallels atherosclerotic plaque growth, and that manipulation of phenomena that impact on calcium depostion also impact on atherosclerotic plaque growth. Vitamins D3 and K2 provide potential potent means of at least partially normalizing these processes.
As the data matures, I am going to enjoy my gouda, Emmenthaler, Gruyere, and feta cheeses, along with a few egg yolks. I'm going to be certain to include healthy oils like olive and canola with my vegetables.
All images courtesy Wikipedia.
Copyright 2007 William Davis, MD