This is a brief but very important article about vitamin K2 that everyone should read. Specifically it relates to a patented form of vitamin K2-MK-7, the most bioavailable and biologically active type of vitamin K – and why is't used in Nexgen+ Sports.


First and foremost most people are familiar with ordinary Vitamin K which is often referred to as Vitamin K1 (phylloquinone). It is a fat soluble vitamin that is found in green leafy vegetables and cereals. Generally a healthy diet rich in dark green leafy vegetables will provide adequate levels of Vitamin K1.


When vitamin K was first discovered in 1929 it was initially thought to only be required for the body to clot blood. Over the past 10 years, a large body of research has focused on new areas of vitamin K metabolism, which include its critical effects on bone and vascular health, cell growth, regulation, migration, proliferation, and apoptosis; immune support; and suppression of chronic inflammatory factors.


However vitamin K is not a single vitamin, much like vitamin E, it consists of many variants all of which behave differently within the human body. Vitamin K2 is of bacterial origin, and there are a number of different types; the most common is short chain vitamin K2-MK4 which is produced endogenously via systemic conversion of vitamin K1 to vitamin MK-4. The long chain vitamin K2 Mk-7, and three other variants MK-8, MK-9 & MK-10, are produced by intestinal bacteria. They are also found in certain foods in very small amounts.


So why the interest in vitamin K2-MK-7 and other types of vitamin K?

There are a number of reasons that Reflex Nutrition insist on the sole use of MK-7. Aside from it being very bioavailable, it also remains in the body for longer, its half-life is around 72 hours meaning that small consistent doses build up to scientifically relevant levels in a matter of days. Other forms like MK-4 do not remain in body for much than a few hours and therefore high dosing is required to provide any beneficial effect.


Effects of higher ingestion of vitamin K2 (4)


Vascular Health

One of the most important reasons for choosing vitamin K2-MK7 in preference to vitamin K1 are the results from scientific studies comparing how vitamin K1 and K2 differ within the human body.


For example, a number of studies compared the absorption and uptake of vitamin K1 and K2 in artery walls and vascular cells within heart muscle. The results of these studies both showed that arterial cell and vascular cells preferentially take up vitamin K2 compared with vitamin K1(1),(2).


The inferior absorption of vitamin K1 into arterial and vascular cells helps explain why K1 has not been shown any significant protection against heart disease. The relevance of vitamin K being absorbed into arteries and vascular cells is simple; it is essential for the activation of vitamin K dependent (VKD) proteins which are involved not only in blood coagulation but in the inhibition of arterial calcification – a major contributor to long term health and potential safeguard against heart disease.



Healthy Bones

A tried and tested indicator of vitamin K activity in the body are levels of activated osteocalcin in the blood. Osteocalcin is made by special bone cells called osteoblasts. When osteoblasts are activated by vitamin K, they ensure that calcium and other minerals like magnesium are literally formed into bone structure increasing overall bone density. Again when compared with vitamin K1, Vitamin K2-MK-7 was scientifically proven to be three times more effective in producing osteocalcin which ultimately leads to a healthier bone structure.(3)


Today the scientific community aim to prevent osteoporosis by looking into strategies that will decrease bone turnover, which is directly related to bone loss. A higher amount of inactivated osteocalcin is directly related to reduced bone density. In a scientific study Vitamin K2-MK-7 was shown to decrease bone turnover and increase bone density(5), further to this there are now a number of studies which support for the use of MK-7 in the prevention of osteoporosis.(6,7,8)


Vitamin K2 MK-7 and Sport

A recent study tested vitamin K2-MK-7’s ability to reduce muscle cramps where it produced significant reductions in both the number of cramps and intensity of muscle cramps(9), the dose used in this study was 100ug, a dose that’s not far off that used in Nexgen+ Sports which provides 75ug. Another interesting area with regard to sport that is being explored is vitamin K2’s effect on VO2 output; it’s an area that we are keeping a very close eye on. An early open trial has shown positive results, watch this space for more news on the research associated with sport.



Even in this brief article we hope to have imparted some valuable information about vitamin K2-MK7. There are new studies on the horizon which will no doubt confirm K2’s vital place in our diets in respect of even further health benefits. You can find out more information on Vitamin K2 MK-7 from the following recommended literature and websites:


Vitamin K2 and the Calcium Paradox, Dr Katie Rheame Bleue
Health Benefits of Vitamin K2, Larry M. Howard, Anthony C. Payne




  1. Spronk HM, 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
  2. Schurgers LJ, Spronk HM, Skepper JN, et al. Post-translational modifications regulate matrix Gla protein function: importance for inhibition of vascular smooth muscle cell calcification.J Thromb Haemost. 2007 Dec;5(12):2503-11.
  3. Schurgers LJ, Teunissen KJ, Hamulyak K, et al. Vitamin K-containing dietary supplements: comparison of synthetic vitamin K1 and natto-derived menaquinone-7. Blood. 2007 Apr 15;109(8):3279-83
  4. Geleijnse JM, Vermeer C, Grobbee DE, et al. Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study. J Nutr. 2004 Nov;134(11):3100-5
  5. Ikeda Y, Iki M, Morita A, et al. Intake of fermented soybeans, natto, is associated with reduced bone loss in postmenopausal women: Japanese Population-Based Osteoporosis (JPOS) Study. J Nutr. 2006 May;136(5):1323-8
  6. Tsukamoto Y. Studies on action of menaquinone-7 in regulation of bone metabolism and its preventive role of osteoporosis. Biofactors. 2004;22(1-4):5-19.
  7. Tsukamoto Y, Ichise H, Kakuda H, Yamaguchi M. Intake of fermented soybean (natto) increases circulating vitamin K2 (menaquinone-7) and gamma-carboxylated osteocalcin concentration in normal individuals. J Bone Miner Metab. 2000;18(4):216-22.
  8. Yamaguchi M. Regulatory mechanism of food factors in bone metabolism and prevention of osteoporosis. Yakugaku Zasshi. 2006 Nov;126(11):1117-37.
  9. Therapeutic Activity and Safety of Vitamin K2-7 in Muscle Cramps. Mehta DS, Vaidya RA, Dound YA, Nabar NS, Pandey SN, Vaidya ADB. The Indian Practitioner Vol.63 No.5