Vitamin K2 is a member of the vitamin K family, a class of nutrients involved in blood clotting and maintaining bone health. Found naturally in meats, cheeses, and eggs, vitamin K2 (also referred to as menaquinone) is also synthesized by bacteria. In addition, many people take vitamin K2 in supplement form.
Vitamin K1 vs. Vitamin K2
Vitamin K1 (also known as phylloquinone) is the form of vitamin K found in plants. Vitamin K is also available in the form of vitamin K3 (also known as menaphthone or menadione).
According to the National Institutes of Health, vitamin K1 is faster-acting, stronger, and more effective for some conditions than other forms of vitamin K. Still, some research suggests that intake of vitamin K2 may offer certain health benefits.
Uses for Vitamin K2
Benefits of Vitamin K2
Here's a look at some key study findings on the health benefits of vitamin K2:
1) Heart Disease
A number of studies suggest that a high intake of vitamin K2 may reduce your risk of heart disease. In a 2004 study from the Journal of Nutrition, for instance, researchers analyzed the dietary intake of vitamin K1 and vitamin K2 among 4,807 people and found that those with the highest intake of either form of vitamin K had a significantly lower risk of coronary heart disease and atherosclerosis. In addition, study members with the highest intake of vitamin K2 were significantly less likely to die from heart disease.
What's more, a 2010 research review published in the journal Maturitas found that vitamin K2 may help protect against cardio-metabolic disorders (such as heart disease, type 2 diabetes, and metabolic syndrome). In their analysis of five studies on vitamin K consumption and incidence of cardio-metabolic disease, the review's authors also found that vitamin K1 may not protect against such disorders.
2) Bone Health
There's some evidence that K2 may boost bone health and reduce risk of osteoporosis. For a 2004 report from Current Pharmaceutical Design, scientists sized up the available research on vitamin K2 and osteoporosis. Results revealed that vitamin K2 may stimulate bone formation and suppress age-related breakdown of bone. Vitamin K2 also appears to sustain bone mineral density and prevent osteoporotic fractures in patients with age-related osteoporosis.
In a more recent research review published in Current Drug Safety, researchers found that combining vitamin K2 with bisphosphonate (a class of drugs that prevent the loss of bone mass) may be useful for preventing fractures in postmenopausal women with osteoporosis and vitamin K deficiency.
Preliminary research indicates that vitamin K2 may aid in the treatment of some forms of cancer. For example, in a 2003 test-tube study from the International Journal of Oncology, researchers found that vitamin K2 may help promote the death of lung cancer cells.
Vitamin K2 is considered safe for most people. However, taking high amounts of any form of vitamin K may be harmful to pregnant and breastfeeding women, patients receiving dialysis treatments due to kidney disease, and people with clotting problems caused by severe liver disease. In addition, vitamin K may interact with certain supplements (including coenzyme Q10 and vitamin E).
Using Vitamin K2 for Health Purposes
There are currently no widespread recommendations for vitamin K supplementation. While vitamin K2 may help with certain health problems, self-treating a chronic condition with vitamin K2 and avoiding standard care may have serious health consequences. Before you begin using vitamin K2, talk to your doctor to determine a safe and effective dosage.
Gast GC, de Roos NM, Sluijs I, Bots ML, Beulens JW, Geleijnse JM, Witteman JC, Grobbee DE, Peeters PH, van der Schouw YT. "A high menaquinone intake reduces the incidence of coronary heart disease." Nutr Metab Cardiovasc Dis. 2009 Sep;19(7):504-10. Epub 2009 Jan 28.
Geleijnse JM, Vermeer C, Grobbee DE, Schurgers LJ, Knapen MH, van der Meer IM, Hofman A, Witteman JC. "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.
Iwamoto J, Takeda T, Sato Y. "Effects of vitamin K2 on osteoporosis." Curr Pharm Des. 2004;10(21):2557-76.
Iwamoto J, Takeda T, Sato Y. "Role of vitamin K2 in the treatment of postmenopausal osteoporosis." Curr Drug Saf. 2006 Jan;1(1):87-97.
Koitaya N, Ezaki J, Nishimuta M, Yamauchi J, Hashizume E, Morishita K, Miyachi M, Sasaki S, Ishimi Y. "Effect of low dose vitamin K2 (MK-4) supplementation on bio-indices in postmenopausal Japanese women." J Nutr Sci Vitaminol (Tokyo). 2009 Feb;55(1):15-21.
Rees K, Guraewal S, Wong YL, Majanbu DL, Mavrodaris A, Stranges S, Kandala NB, Clarke A, Franco OH. "Is vitamin K consumption associated with cardio-metabolic disorders? A systematic review." Maturitas. 2010 Oct;67(2):121-8. Epub 2010 Jun 17.
Yoshida T, Miyazawa K, Kasuga I, Yokoyama T, Minemura K, Ustumi K, Aoshima M, Ohyashiki K. "Apoptosis induction of vitamin K2 in lung carcinoma cell lines: the possibility of vitamin K2 therapy for lung cancer." Int J Oncol. 2003 Sep;23(3):627-32.