Meet Vitamin D’s Best Friend - Vitamin K2

Vitamin D and vitamin K2 are like our body’s best relay race team when it comes to bone and heart health.  While vitamin D helps your body absorb calcium for bone health, it is vitamin K2 that directs that calcium into the bones.

Because K2 is needed to direct calcium to the bones, it is especially important during childhood, puberty, pregnancy and in osteoporosis prevention and treatment.  Studies have shown that postmenopausal women benefited from a daily low dose of vitamin K2.  Three years of vitamin K2 supplementation resulted in reduced age-related decline in bone mineral density!  In addition, women already diagnosed with osteopenia improved their bone health with vitamin K2 supplementation so it’s never too late to start!

Because vitamin D stimulates calcium absorption from the gut, high doses of vitamin D without its best friend K2 can result in calcium that doesn’t know where to go!  This can result in calcium build-up in areas of the body you don’t want.

One of the areas we don’t want calcium build-up is in the blood vessels because this leads to calcification and hardening of the arteries, increasing the risk of cardiovascular disease.  

Scientific studies have demonstrated that vitamin K2 supplementation results in a significant reduction in artery stiffness and a slower progression of calcification!

Unfortunately, Western diets are notorious for being K2 deficient which often leaves us with supplementation as the option.  

You might be thinking - but I eat lots of leafy green vegetables?  Surely I get enough vitamin K2!

There are two types of vitamin K - K1 and K2.  Vitamin K1 is found in green leafy vegetables, broccoli and kale.  The major function of vitamin K1 is to help in blood clotting.  Vitamin K2 on the other hand is mainly found in fermented foods such as aged cheese, yogurt, natto and cured fish.  Vitamin K2 is necessary for optimal bone and heart health!  In fact, Japanese people that consume natto were shown to have lower rates of bone and heart disease.  

Vitamin K2 is affectionately referred to as “the forgotten vitamin” because of its importance for bone and heart health yet it receives little recognition.  

Vitamin K2 makes a great pairing with your vitamin D supplement and is very tolerable and safe!

References:

Study References:

a. Schwalfenberg, G.K., Vitamins K1 and K2: The Emerging Group of Vitamins Required for Human Health. J Nutr Metab, 2017. 2017: p. 6254836.
b. Fujita, Y., et al., Association between vitamin K intake from fermented soybeans, natto, and bone mineral density in elderly Japanese men: the Fujiwara-kyo Osteoporosis Risk in Men (FORMEN) study. Osteoporos Int, 2012. 23(2): p. 705-14.

c. Knapen, M.H., et al., Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy post- menopausal women. Osteoporos Int, 2013. 24(9): p. 2499-507.
d. Kaneki, M., et al., Japanese fermented soybean food as the major determinant of the large geographic difference in circulating levels of vitamin K2: possible implications for hip-fracture risk. Nutrition, 2001. 17(4): p. 315-21.

e. Geleijnse, J.M., et al., Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study. J Nutr, 2004. 134(11): p. 3100-5.
f. Knapen, M.H., et al., Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women. A dou- ble-blind randomised clinical trial. Thromb Haemost, 2015. 113(5): p. 1135-44.

g. Kurnatowska, I., et al., Effect of vitamin K2 on progression of atherosclerosis and vascular calcification in nondialyzed patients with chronic kidney disease stages 3-5. Pol Arch Med Wewn, 2015. 125(9): p. 631-40.
h. van Summeren, M.J., et al., The effect of menaquinone-7 (vitamin K2) supplementation on osteocalcin carboxylation in healthy prepubertal children. Br J Nutr, 2009. 102(8): p. 1171-8.

i. Moller, M., et al., Bioavailability and Chemical/ Functional Aspects of Synthetic MK-7 vs Fermentation-Derived MK-7 in Ran- domised Controlled Trials. Int J Vitam Nutr Res, 2016: p. 1-15.
j. McFarlin, B.K., A.L. Henning, and A.S. Venable, Oral Consumption of Vitamin K2 for 8 Weeks Associated With Increased Maximal Cardiac Output During Exercise. Altern Ther Health Med, 2017. 23(4): p. 26-32.

k. Riphagen, I.J., et al., Prevalence and Effects of Functional Vitamin K Insufficiency: The PREVEND Study. Nutrients, 2017. 9(12): p. 1334
l. Aoun, M., et al., High Dephosphorylated-Uncarboxylated MGP in Hemodialysis patients: risk factors and response to vitamin K2, A pre-post intervention clinical trial. BMC Nephrol, 2017. 18(1): p. 191.

m. Mansour, A.G., et al., Vitamin K2 supplementation and arterial stiffness among renal transplant recipients-a single-arm, single- center clinical trial. J Am Soc Hypertens, 2017.
n. Marles, R.J., A.L. Roe, and H.A. Oketch-Rabah, US Pharmacopeial Convention safety evaluation of menaquinone-7, a form of vitamin K. Nutr Rev, 2017. 75(7): p. 553-578.

o. Popko, J., et al., Decreased Levels of Circulating Carboxylated Osteocalcin in Children with Low Energy Fractures: A Pilot Study. Nutrients, 2018. 10(6).
p. Wei, F.F., et al., Inactive matrix Gla protein is a novel circulating biomarker predicting retinal arteriolar narrowing in humans. Sci Rep, 2018. 8(1): p. 15088.

q. Li, Y., et al., Effect of vitamin K2 on type 2 diabetes mellitus: A review. Diabetes Res Clin Pract, 2018. 136: p. 39-51.
r. Myneni, V.D. and E. Mezey, Regulation of bone remodeling by vitamin K2. Oral Dis, 2017. 23(8): p. 1021-1028.
s. van Ballegooijen, A.J. and J.W. Beulens, The Role of Vitamin K Status in Cardiovascular Health: Evidence from Observational and Clinical Studies. Curr Nutr Rep, 2017. 6(3): p. 197-205.
t. van den Heuvel, J.M., et al., NOACs replace VKA as preferred oral anticoagulant among new patients: a drug utilization study in 560 pharmacies in The Netherlands. Thromb J, 2018. 16: p. 7.

Editorial References

1. Marles, R.J., A.L. Roe, and H.A. Oketch-Rabah, US Pharmacopeial Convention safety evaluation of menaquinone-7, a form of vi- tamin K. Nutr Rev, 2017. 75(7): p. 553-578.
2. Schurgers, L.J., et al., Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood, 2007. 109(8): p. 3279-83.

3. Gebuis, E.P., et al., Vitamin K1 supplementation to improve the stability of anticoagulation therapy with vitamin K antagonists: a dose-finding study. Haematologica, 2011. 96(4): p. 583- 9.
4. Li, R.C., et al., Dietary vitamin K intake and anticoagulation control during the initiation phase of warfarin therapy: a prospective cohort study. Thromb Haemost, 2013. 110(1): p. 195-6.

5. Majeed, H., et al., Effect of 200muG/day of vitamin K1 on the variability of anticoagulation control in patients on warfarin: a ran- domized controlled trial. Thromb Res, 2013. 132(3): p. 329- 35.
6. Sconce, E., et al., Vitamin K supplementation can improve stability of anticoagulation for patients with unexplained variability in response to warfarin. Blood, 2007. 109(6): p. 2419-23.

7. Sconce, E., et al., Patients with unstable control have a poorer dietary intake of vitamin K compared to patients with stable control of anticoagulation. Thromb Haemost, 2005. 93(5): p. 872-5.
8. Mekaj, Y.H., et al., New oral anticoagulants: their advantages and disadvantages compared with vitamin K antagonists in the prevention and treatment of patients with thromboembolic events. Ther Clin Risk Manag, 2015. 11: p. 967-77.

9. Spronk HM1, Soute BA, Schurgers LJ, Thijssen HH, De Mey JG, Vermeer C. Tissue-specific utilization of menaquinone-4 results in the prevention of arterial calcification in warfarin-treated rats. J Vasc Res. 2003 Nov-Dec; 40(6):531-7. Epub 2003 Dec 3