Synergy of D3 and K2
New research is focusing on the synergistic relationship between vitamin K2 and vitamin D3 for bone and cardiovascular health.1 Vitamin K is essential for the proper utilization of calcium. Through its activation of the protein osteocalcin, vitamin K helps to bind newly absorbed calcium to the mineral matrix in bone. In addition, vitamin K has been found to help maintain bone mineral density by decreasing the activity of osteoclasts, a cell that breaks down the bone matrix.2 Vitamin K also provides critical cardiovascular protection by helping to activate matrix Gla protein (MGP), an inhibitor of circulatory calcification.3,4 Thus, vitamin K and vitamin D not only share similar qualities, but they also act synergistically within the body.5
In addition to supporting bone health, vitamin D plays an important role maintaining cardiovascular health and immune function and promoting an overall sense of well-being. While vitamin D has long been known to assist calcium absorption, it is vitamin K, through its carboxylation of osteocalcin, which guides this calcium to bones and prevents their absorption into organs, joint spaces, and arteries. Vitamin K occurs in two main forms: K1 (phylloquinone), derived from foods such as green leafy vegetables and K2 (menaquinone), which is a group of related compounds differentiated by their side chains. Numerous studies have shown that vitamin K2 as MK-7 is the more bioavailable form of the nutrient and more powerfully influence bone building that K1.7 In addition, though both reach the liver, most of the K1 is used for purposes of coagulation, with little left over to support the body’s needs elsewhere.8 The profoundly different degree of bioavailability between K1 and K2 is due to differences in structure: Only 10-20% of vitamin K1 that is absorbed from food even reaches the circulation, while the long side-chain of vitamin K2 allows it to bind with fat particles in circulation and facilitate its arrival at soft tissue, bones and arteries. There are two forms of vitamin K2 commonly used in supplements: MK-4 and MK-7. The MK-7 form has been shown to have six times the activity of MK-4 in the blood.7 MK-7 has also been found to remain in the blood approximately nine times as long as the MK-4 (72 hours vs 4 hours), making it the optimal form of K2 for health. The MK-7 in this formula is backed by extensive research. Dr. Leon Schurgers, world-renowned expert in vitamin K2 as MK-7 research for cardiovascular and bone health, and his team of research scientists have conducted over 15 clinical trials on MK-7 through the University of Maastricht.
Vitamin K Depletion
Although most people consume adequate dietary vitamin K to maintain sufficient blood clotting, most do not consume enough to meet cardiovascular and bone health needs. In fact, approximately 70% of the western population is deficient in vitamin K2. Compromised intestinal absorption can also lead to insufficient K2 levels leaving calcium vulnerable to be exported out of bone and into other tissues. Medications such as antibiotics, cholesterol-lowering medications and laxatives have also been found to contribute to a deficiency of vitamin K.10
Building and maintaining healthy bones requires a number of key nutrients including vitamin K, for proper binding of calcium to the bone matrix. A 2005 study from northern Finland found that those with greater levels of vitamin K-carboxylated osteocalcin had stronger bones than those with lower levels of the protein. A Japanese study found superior bone health among women who were frequent MK-7-rich natto eaters than those who were not.11 Another randomized study which split 172 women into a vitamin K2 group, a vitamin D3 group, a vitamin K2 and D3 group, and a placebo group for two years found that the combination of vitamin D3 and K2 had the most benefits for supporting bone health among the groups.12
Cardiovascular Health and Blood Sugar Balance
Vitamin K plays a key role in supporting the cardiovascular system as well as blood sugar balance already within normal levels. In a large population study, researchers found that those who consumed high amounts of K2 had significantly better cardiovascular health markers compared to those given vitamin K1.3 Studies have also shown vitamin K supports healthy blood sugar metabolism.13,14
New evidence also suggests vitamin K plays a central role in balancing immune health. Recent studies have shown that both vitamins D and K impart immune-modulating effects. In the Framingham Offspring Study, one of the longest standing studies on generational health, higher serum levels of vitamins D and K were associated with stronger immune function and a balanced inflammatory response.15,16 In a 2011 study, vitamin K was also found to suppress various markers of the immune system.17
Long-term vitamin K deficiencies are linked to bone fragility, arterial calcification, and genomic instability. These issues are related to a loss of vitamin K-dependent proteins not required for short-term survival but presenting long-term health challenges.
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12. Choi JH, Yu J, Choi H, An JH, Kim SW, Parks KS, Jang HC, Kim SY, Shin CS. Vitamin K2 supplementation improves insulin sensitivity via osteocalcin metabolism: a placebo-controlled trial. Diabetes Care 2011;34(9):147.
13. Shea MK, Booth SL, massaro JM, Jacques PF, D’Agostino RB Sr, Dawson-Hughes B, Ordovas JM, O’Donnell CJ, Kathiresan S, Keaney JF Jr, Vasan RS, Benjamin EJ. Vitamin K and vitamin D status: associations with inflammatory markers in the Framingham Offspring Study. Am J Epidemiol 2008; 167(3):313-20.
14. Iijima H, Shinzaki S, Takehara T. The importance of vitamins D and K for the bone health and immune function in inflammatory bowel disease. Curr Opin Clin Nutr Metab Care 2012;15(6):635-40.
15. Checker R, Sharma D, Sandur SK, Khan NM, Patwardhan RS, Kohli V, Sainis KB. Vitamin K suppressed inflammatory and immune responses in a redox-dependent makker. Free Radic Res 2011;45(8):975-85. Epub 2011 Jun 9.