Vitamin K Functions
K2 is a member of the synergistic bone and heart health team - which also includes calcium, magnesium and vitamins A and D. In essence, vitamin D helps absorb the calcium from the intestines, vitamin K2 tells it where to go.
(1) OSTEOCALCIN and (2) MGP (Matrix GLA Protein)
Put calcium in bones/teeth and not in soft tissue (E.g. arteries, cartilage)
“Impairment of the function of OSTEOCALCIN and MGP due to incomplete carboxylation results in an increased risk for developing osteoporosis and vascular calcification, respectively, and is an unexpected side effect of treatment with oral anticoagulants. . . In healthy individuals, substantial fractions of OSTEOCALCIN and MGP circulate as incompletely carboxylated species, indicating that the majority of these individuals is subclinically vitamin K-deficient. Potential new application areas for vitamin K are therefore its use in dietary supplements and functional foods for healthy individuals to prevent bone and vascular disease, as well as for patients on oral anticoagulant treatment to offer them protection against coumarin-induced side effects”
Cranenburg EC, Schurgers LJ, Vermeer C.
Vitamin K: The coagulation vitamin that
became omnipotent. Thromb Haemost. 2007 Jul;98(1):120-5.
Vitamin K2-dependent OSTEOCALCIN activation seems to concurrently strengthen bones and inhibit (and possibly reverse) soft tissue calcification - Vitamin K2 functions as a cofactor for the enzyme (γ-glutamylcarboxylase) that activates (catalyzes the carboxylation of) a protein hormone called OSTEOCALCIN, (produced by bone-building osteoblasts), which is needed to bind calcium into hydroxyapatite crystals forming the bone matrix. OSTEOCALCIN also appears to help prevent calcium from depositing into your arteries.
Technically - the K-dependent enzyme catalyzes the carboxylation of the amino acid glutamic acid, resulting in gamma-carboxyglutamic acid (Gla); Gla's make it possible to bind calcium.
E.g. (a) OSTEOCALCIN contains 3 residues of Gla, which can bind calcium into bone,
and (b) K-dependent gamma-carboxylation of glutamic acid residues in clotting factor proteins makes it possible for themto bind calcium ions, which activates the blood clotting factors
-Not only is K2 needed to help osteoblasts produce OSTEOCALCIN to bind calcium into bones, K2 also prevents osteoclasts from breaking down bone
-Studies of “healthy”adults have found high levels of uncarboxylated (not activated) OSTEOCALCIN and MGP in all subjects tested - K2 activates both proteins, so high levels of their inactive forms indicate a lack of sufficient K2 to do the job.
Cranenburg EC, Schurgers LJ. Thromb Haemost. 2007 Jul;98(1):120-5
-Vitamin K2 is three times more effective than synthetic vitamin K1 in raising OSTEOCALCIN - which controls the building of bone
Schurgers LJ, Teunissen KJF, Hamulyak K, Knapen MHJ, Hogne V, Vermeer C. “Vitamin K-containing dietary supplements: Comparison of synthetic vitamin K1 and natto-derived menaquinone-7” Blood. 2006
-Vitamin K needs increase with age - individuals >70 yrsrequire higher levels of vitamin K to keep levels of uncarboxylated (inactivated) vitamin-K dependent protein low.
Tsugawa N, Shiraki M, et al. Vitamin K status of healthy Japanese women: age-related vitamin K requirement for gamma-carboxylation of osteocalcin. Am J Clin Nutr. 2006 Feb;83(2):380-6
Vitamin K and vitamin D together increase Matrix GLA Protein (MGP), which protects soft tissue from calcification -by preventing calcium crystal formation E.g. in blood vessels, bone spursand cartilage
Vitamin K in hydrogenated canola and soybean oils(typically found in processed foods) is changed to an unnatural form (dihydrophylloquinone), which is unable to activate OSTEOCALCIN and MGP - such that regularly eating processed / fast foods together with a diet low in leafy greens greatly increases risk of functional K-deficiency
Booth SL, Lichtenstein AH, et al. Effects of a hydrogenated form of vitamin K on bone formation and resorptionAm J Clin Nutr. 2001 Dec;74(6):783-90
Those consuming higher amounts of dihydrophylloquinone were found to have lower bone mineral density at the neck, hip and spine
Troy LM, Jacques PF, Hannan MT, Kiel DP, Lichtenstein AH, Kennedy ET, Booth SL. Dihydrophylloquinone intake is associated with low bone mineral density in men and women. Am J Clin Nutr. 2007 Aug;86(2):504-8.