If you have seen K2 supplements in the market and are wondering if you at all need them, here’s all you need to know. In the human diet, vitamin K is found in two main forms: K1 or phylloquinone and K2, a group of compounds known as menaquinones (MKs). Depending on the length of their side chain, K2 subtypes range from MK-4 to MK-13.
MK-4 and MK-7 are the common and better-researched subtypes of K2 found in food. While MK-4 is found in meat and eggs, MK-7 and the other longer-chain subtypes are found in fermented food. MK-7 is better absorbed in the body and remains longer in circulation.
K1 is found in leafy greens, legumes, herbs, and plant oils, while K2 is found in varying quantities in pasture-raised animal products like meat, eggs, and milk and fermented foods like natto (fermented soy) and cheese from grass-fed dairy. The body also converts some K1 into K2. It’s now known that vitamin K doesn’t just help with blood clotting but it also protects against bone loss and heart disease. And these health benefits are provided by K2 rather than K1. Here’s a look at the health benefits of K2.
1. Promotes Heart Health
Vitamin K regulates calcium in the body by modifying proteins in a process called carboxylation so that they can bind to calcium ions. While K1 uses carboxylation to clot blood, K2, in particular, prevents calcium build-up in the arteries by modifying the matrix gla-protein (MGP). Calcium deposition in the arteries or arterial calcification stiffens up the arteries and raises blood pressure. This increases the risk of heart disease as well as all-cause mortality. Taking warfarin, a blood thinning medicine that inhibits the action of vitamin K, has been seen to induce arterial calcification. But in an animal study, vitamin K2 could reverse the damage induced by warfarin.1
Vitamin K2, especially the subtypes MK-7, MK-8, and MK-9, have been found to improve heart health by preventing the thickening of arteries. This means eating foods like natto or cheese, that contain the longer-chain K2 subtypes, rather than meat or eggs which contain MK-4.
Observational studies on human beings have also found that the highest intake of K2 is linked with the lowest prevalence of arterial calcification and mortality due to heart disease. In fact, eating foods rich in K2 reduces the risk of both arterial calcification and heart disease by as much as 50%, and for every 10 mcg increase in K2 intake, coronary events drop by 9%.2 3
In 2015, researchers tested the effect of K2 on heart health directly through an intervention trial on postmenopausal women – postmenopausal women are susceptible to heart disease due to low estrogen levels – by giving them 180 mcg K2 in the form of MK-7 for 3 years. It was found that K2 reduced arterial stiffness in all women but more significantly in those who already had a stiff carotid artery.4 However, no such beneficial link was found for K1 intake.5
2. Lowers The Risk Of Osteoporosis
K2 can also improve your bone health. Similar to how it modifies MGP in the arteries, K2 also activates osteocalcin, the protein responsible for anchoring calcium to bones. So, an adequate supply of vitamin K2 is crucial for the delivery of calcium to your bones and to reduce the risk of osteoporosis.6 Both MK-4 and MK-7 are more efficient in improving bone health than K1.
It has been observed that Japanese women whose traditional diet comprises of natto, a fermented soy dish with the highest amount of K2 (MK-7), suffer from fewer incidences of fractures and osteoporosis than their American counterparts who have never had natto. Research suggests that increasing K2 intake can lower age-related bone loss, reduce the risk of fracture in patients of osteoporosis, especially postmenopausal women, and increase the effectiveness of osteoporosis medicines.7
More studies have been conducted with MK-4, and it has shown to be able to prevent fractures and bone loss but at a high dose of 45 mg. It is difficult to get this amount from dietary sources like meat or eggs.
In a study in Japan, MK-4 supplementation prevented vertebral fractures by 60%, hip fractures by 77%, and nonvertebral fractures by 81%. Another study on patients of osteoporosis showed that MK-4 supplements maintained the lumbar bone density of the participants and reduced the incidence of fractures, as opposed to calcium and placebo supplements. The K2 group also had 65% fewer fractures. In another study, menopausal women who took 180 mcg K2 (MK-7) for 3 years lost less bone mineral density in parts of the spine and femoral bone.8 9 10
3. Promotes Dental Health
Weston Price, a 20th century dentist, studied non-industrial cultures across the world and claimed that fat-soluble vitamins have a beneficial effect on dental health. He treated and healed dental caries with cod liver oil (source of vitamin D) with butter oil from grass-fed cows, which he said contains “activator x.” Modern science suggests that activator x is vitamin K2. 11
Keeping up your K2 intake could also bode well for your teeth as it can work in multiple ways to prevent tooth decay. A new line of research suggests that teeth are naturally cleaned and protected by a fluid flow that is controlled by the brain. Eating sugars and refined foods causes oxidative stress in the brain, and this in turn hinders the fluid flow. As a result, teeth become more vulnerable to bacterial attack and develop caries. It can act as an antioxidant in the brain and maintain proper fluid flow.12 It also activates the osteocalcin protein that is responsible for calcium metabolism in the teeth. So in the absence of K2, calcium deposition in the teeth or the repair of dental caries is hindered. Moreover, K2 modifies the pH (acidity) of saliva so that it can help remineralize affected teeth and reduce bacteria in the cavity.13 14 While clinical trials have not been conducted on K2’s effect on teeth, dairy products, ideally obtained from grass-fed cattle, could help prevent tooth decay and remineralize your teeth.
4. May Improve Insulin Sensitivity
K2 might have a role to play in preventing and managing type 2 diabetes, but further research is needed to firm up this benefit. K2 supposedly increases insulin sensitivity (a measure of how receptive your cells are to insulin and therefore glucose uptake) by regulating osteocalcin metabolism.15 And since K2 is involved in osteocalcin metabolism, it can improve insulin sensitivity.
If you want to increase your K2 intake through your diet to manage your diabetes symptoms, consult a nutritionist to know your adequate intakes of MK-4 rich foods like meat, eggs, or butter.
A 2011 study found that giving 30 mg MK-4 supplements daily to healthy young men for 4 weeks increased their insulin sensitivity by increasing the amount of activated osteocalcin.16 Another review of the few studies conducted so far on the effect of K2 on type 2 diabetes finds that it can improve insulin sensitivity and glucose control by lowering inflammation and lipid levels as well.17 However, further studies are required before K2 supplementation can be regarded as a standard course of treatment for diabetes.
5. Fights Inflammation
The MK-7 form of vitamin K2 is said to prevent inflammation. It is believed to do this by inhibiting pro-inflammatory markers produced by white blood cells called monocytes. It may even prevent oxidative damage in nerve cells.18 19 While more research is needed to firm up the anti-inflammatory benefits of K2, you can still have it in dietary amounts for the other health benefits. You can find MK-7 in large quantities in natto, a Japanese dish made of fermented soy. However, since its texture and flavor are not familiar to the American palate, most people opt for natto supplements. If you want to get your MK-7 naturally, try cheeses like Gouda and brie.20
6. Fights Cancer
Given that K2 might have a role to play in curbing inflammation, it’s natural to expect that it may have a role in cancer prevention as well. In an epidemiological study conducted by the European Prospective Investigation into Cancer and Nutrition, it was seen that people with the highest intake of K2 (from dairy products such as cheese but not meat) had the lowest risk of developing cancer. There was even a 30% lower risk of death from cancer. During the 10 year plus follow-up, 1755 cancer incidences were reported, of which 458 were fatal. K2 intake seemed to prevent dying from cancer more than preventing overall cancer incidence. Men with lung and, especially, advanced-stage prostate cancer seemed to benefit more significantly, with the risk becoming 63% lower for advanced prostate cancer patients.21 22
A high intake of K2 from dairy products but not meat has been seen to reduce the risk of death from advanced stage prostate cancer.
This ability of K2 to prevent cancers from becoming fatal could be seen in a couple of other trials on liver cancer as well. Liver cancer is notorious for relapse even after surgical or curative treatment, but patients given a daily dose of 45 mg K2 survived longer and had fewer relapses.23 24
Lab studies suggest that K2 could also be used in lung cancer therapy as an adjuvant to the common chemo drug cisplatin. It could also induce death in leukemia (blood or bone marrow cancer) cells together with vitamin D3.25 26 K2 has also shown promise in treating cancers caused by abnormal blood cells – a condition known as myelodysplastic syndrome.27 28
However, K1 has not shown any of these anticancer benefits.
7. May Protect The Brain
Early-stage research suggests that MK-4 may have a role to play in preventing cognitive decline. Vitamin K, chiefly MK-4, is found in high concentrations in areas of the brain that contain myelinated cells (these are cells with a protective covering called myelin sheath). Loss of myelin causes cognitive decline and changes in behavior associated with old age. MK-4 is involved in the synthesis of sphingolipids, a kind of fat found in nerve cells and brain cells that are in turn involved in the metabolism of myelin. This is still a new area of research, but researchers feel that K2 will be considered an important nutrient for brain health in the future.
8. May Improve Symptoms Of Autoimmune Disorders
Preliminary research on other benefits of K2 shows that it may improve autoimmune diseases like rheumatoid arthritis and multiple sclerosis. K2 showed beneficial effects in a study on encephalomyelitis, which is an animal model of multiple sclerosis.29 30
9. May Improve Varicose Veins
It has been claimed that vitamin K2 can improve symptoms of varicose veins through MGP metabolism. MGP is the protein that keeps calcium out of soft tissues like arteries and veins. A study found that people with varicose veins had higher amounts of inactive MGP. While a study linking K2 consumption with improvement in varicose vein symptoms has not been conducted yet, we know from the heart health studies that K2 activates MGP and can possibly improve the condition.31
10. May Prevent Skin Wrinkling
One reason for your double chin and wrinkled skin is calcification of elastin, a protein that keeps skin elastic, and vitamin K2 may prevent this by activating MGP.32 A study on patients of pseudoxanthoma elasticum (PXE), a genetic condition where the skin wrinkles excessively, found that the patients had 30% less activated MGP than healthy controls.33 However, in the case of PXE, the cure is not as straightforward as supplementing K2.34 Incidentally, women with excessive wrinkles also have low bone mass, which may indicate a low level of K2.35 So in healthy people, a high K2 intake may have a protective effect on the skin.
How Much K2 Should You Have?
There is no recommended intake for vitamin K, but the Food and Nutrition Board has established the adequate intake (AI) levels at 120 mcg for adult men and 90 mcg for adult women, even when they are pregnant or lactating. The individual intake levels for K1 and K2 have not been established yet.
Foods containing vitamin K2 include natto, goose live pate, certain types of hard and soft cheeses, meat, and eggs. Here’s a complete list of top foods containing vitamin K. It’s essential to not give up on leafy greens since some of the K1 from leafy greens is also converted into K2 inside the body. It’s possible to get enough MK-7 from natto (998 mcg/100 g) and goose liver pate (369 mcg/100 g) since its beneficial dose has been found to be between 100 and 360 mcg. For MK-4, since the standard dose used in most studies has been as high as 45 mg, you may need supplements. Remember that you have to up your K2 intake if you are on vitamin D supplements, since D may use up all the K2 in your body and cause a deficiency. The symptoms of K2 deficiency are not obvious, but eventually a deficiency may affect your heart, bone, and skin health.
|↑1||Schurgers, Leon J., Henri MH Spronk, Berry AM Soute, Paul M. Schiffers, Jo GR DeMey, and Cees Vermeer. “Regression of warfarin-induced medial elastocalcinosis by high intake of vitamin K in rats.” Blood 109, no. 7 (2007): 2823-2831.|
|↑2||Geleijnse, Johanna M., Cees Vermeer, Diederick E. Grobbee, Leon J. Schurgers, Marjo HJ Knapen, Irene M. Van Der Meer, Albert Hofman, and Jacqueline CM Witteman. “Dietary intake of menaquinone is associated with a reduced risk of coronary heart disease: the Rotterdam Study.” The Journal of nutrition 134, no. 11 (2004): 3100-3105.|
|↑3||Gast, Gerrie-Cor M., Nicole M. de Roos, Ivonne Sluijs, Michiel L. Bots, Joline WJ Beulens, Johanna M. Geleijnse, Jacqueline C. Witteman, Diederick E. Grobbee, Petra HM Peeters, and Yvonne T. van der Schouw. “A high menaquinone intake reduces the incidence of coronary heart disease.” Nutrition, Metabolism and Cardiovascular Diseases 19, no. 7 (2009): 504-510.|
|↑4||Knapen, Marjo HJ, Lavienja AJLM Braam, Nadja E. Drummen, Otto Bekers, Arnold PG Hoeks, and Cees Vermeer. “Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women.” Thrombosis and haemostasis 114, no. 05 (2015): 1135-1144.|
|↑5||Beulens, Joline WJ, Michiel L. Bots, Femke Atsma, Marie-Louise EL Bartelink, Matthias Prokop, Johanna M. Geleijnse, Jacqueline CM Witteman, Diederick E. Grobbee, and Yvonne T. Van Der Schouw. “High dietary menaquinone intake is associated with reduced coronary calcification.” Atherosclerosis 203, no. 2 (2009): 489-493.|
|↑6||Iwamoto, Jun, Tsuyoshi Takeda, and Yoshihiro Sato. “Effects of vitamin K2 on osteoporosis.” Current pharmaceutical design 10, no. 21 (2004): 2557-2576.|
|↑7||Vitamin K. Osteoporosis Australia.|
|↑8||Cockayne, Sarah, Joy Adamson, Susan Lanham-New, Martin J. Shearer, Simon Gilbody, and David J. Torgerson. “Vitamin K and the prevention of fractures: systematic review and meta-analysis of randomized controlled trials.” Archives of Internal Medicine 166, no. 12 (2006): 1256-1261.|
|↑9||Shiraki, Masataka, Yumiko Shiraki, Choju Aoki, and Masakazu Miura. “Vitamin K2 (menatetrenone) effectively prevents fractures and sustains lumbar bone mineral density in osteoporosis.” Journal of bone and mineral research 15, no. 3 (2000): 515-521.|
|↑10||Knapen, M. H. J., N. E. Drummen, Eline Smit, C. Vermeer, and E. Theuwissen. “Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women.” Osteoporosis International 24, no. 9 (2013): 2499-2507.|
|↑11, ↑13||On the Trail of the Elusive X-Factor: A Sixty-Two-Year-Old Mystery Finally Solved. The Weston A. Price Foundation.|
|↑12||Southward, Ken. “A hypothetical role for vitamin K2 in the endocrine and exocrine aspects of dental caries.” Medical hypotheses 84, no. 3 (2015): 276-280.|
|↑14||Gordeladze, Jan Oxholm, Maria A. Landin, Gaute Floer Johnsen, Håvard Jostein Haugen, and Harald Osmundsen. “Vitamin K2 and its Impact on Tooth Epigenetics.” In Vitamin K2-Vital for Health and Wellbeing. InTech, 2017.|
|↑15||Bilotta, F.L., Arcidiacono, B., Messineo, S., Greco, M., Chiefari, E., Britti, D., Nakanishi, T., Foti, D.P. and Brunetti, A., 2018. Insulin and osteocalcin: further evidence for a mutual cross-talk. Endocrine, 59(3), pp.622-632.|
|↑16||Choi, Hyung Jin, Juyoun Yu, Hosanna Choi, Jee Hyun An, Sang Wan Kim, Kyong Soo Park, Hak C. Jang, Seong Yeon Kim, and Chan Soo Shin. “Vitamin K2 supplementation improves insulin sensitivity via osteocalcin metabolism: a placebo-controlled trial.” Diabetes care 34, no. 9 (2011): e147-e147.|
|↑17||Li, Yan, Jie peng Chen, Lili Duan, and Shuzhuang Li. “Effect of vitamin K2 on type 2 diabetes mellitus: A review.” Diabetes research and clinical practice 136 (2018): 39-51.|
|↑18||Pan, Min-Hsiung, Katarzyna Maresz, Pei-Sheng Lee, Jia-Ching Wu, Chi-Tang Ho, Janusz Popko, Dilip S. Mehta, Sidney J. Stohs, and Vladimir Badmaev. “Inhibition of TNF-α, IL-1α, and IL-1β by pretreatment of human monocyte-derived macrophages with menaquinone-7 and cell activation with TLR agonists in vitro.” Journal of medicinal food 19, no. 7 (2016): 663-669.|
|↑19||Li, Jianrong, Judith C. Lin, Hong Wang, James W. Peterson, Barbara C. Furie, Bruce Furie, Sara L. Booth, Joseph J. Volpe, and Paul A. Rosenberg. “Novel role of vitamin k in preventing oxidative injury to developing oligodendrocytes and neurons.” Journal of Neuroscience 23, no. 13 (2003): 5816-5826.|
|↑20||Rheaume-Bleue, Kate. Vitamin K2 and the calcium paradox: how a little-known vitamin could save your life. John Wiley & Sons, 2011.|
|↑21||Nimptsch, Katharina, Sabine Rohrmann, Rudolf Kaaks, and Jakob Linseisen. “Dietary vitamin K intake in relation to cancer incidence and mortality: results from the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg)–.” The American journal of clinical nutrition 91, no. 5 (2010): 1348-1358.|
|↑22||Nimptsch, Katharina, Sabine Rohrmann, and Jakob Linseisen. “Dietary intake of vitamin K and risk of prostate cancer in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg)–.” The American journal of clinical nutrition 87, no. 4 (2008): 985-992.|
|↑23||Mizuta, Toshihiko, Iwata Ozaki, Yuichiro Eguchi, Tsutomu Yasutake, Seiji Kawazoe, Kazuma Fujimoto, and Kyosuke Yamamoto. “The effect of menatetrenone, a vitamin K2 analog, on disease recurrence and survival in patients with hepatocellular carcinoma after curative treatment.” Cancer 106, no. 4 (2006): 867-872.|
|↑24||Ishizuka, Mitsuru, Keiichi Kubota, Mitsugi Shimoda, Junji Kita, Masato Kato, Kyung Hwa Park, and Takayuki Shiraki. “Effect of menatetrenone, a vitamin k2 analog, on recurrence of hepatocellular carcinoma after surgical resection: a prospective randomized controlled trial.” Anticancer research 32, no. 12 (2012): 5415-5420.|
|↑25||Yoshida, Tsuyoshi, Keisuke Miyazawa, Ikuma Kasuga, Tomohisa Yokoyama, Kazushige Minemura, Kenta Ustumi, Masahiro Aoshima, and Kazuma Ohyashiki. “Apoptosis induction of vitamin K2 in lung carcinoma cell lines: the possibility of vitamin K2 therapy for lung cancer.” International journal of oncology 23, no. 3 (2003): 627-632.|
|↑26||Iguchi, Tomotaka, Keisuke Miyazawa, Minoru Asada, Akihiko Gotoh, Shuki Mizutani, and Kazuma Ohyashiki. “Combined treatment of leukemia cells with vitamin K2 and 1α, 25-dihydroxy vitamin D3 enhances monocytic differentiation along with becoming resistant to apoptosis by induction of cytoplasmic p21CIP1.” International journal of oncology 27, no. 4 (2005): 893-900.|
|↑27||Miyazawa, K., J. Nishimaki, K. Ohyashiki, S. Enomoto, S. Kuriya, R. Fukuda, T. Hotta et al. “Vitamin K 2 therapy for myelodysplastic syndromes (MDS) and post-MDS acute myeloid leukemia: information through a questionnaire survey of multi-center pilot studies in Japan.” Leukemia 14, no. 6 (2000): 1156.|
|↑28||Abe, Yasunobu, Koichiro Muta, Nobuhisa Hirase, Ilseung Choi, Takamitsu Matsushima, Keiichi Hara, Fumihiro Taguchi et al. “Vitamin K2 therapy for myelodysplastic syndrome.” [Rinsho ketsueki] The Japanese journal of clinical hematology 43, no. 2 (2002): 117-121.|
|↑29||Moriya, Masayuki, Yuji Nakatsuji, Tatsusada Okuno, Toshimitsu Hamasaki, Makoto Sawada, and Saburo Sakoda. “Vitamin K2 ameliorates experimental autoimmune encephalomyelitis in Lewis rats.” Journal of neuroimmunology 170, no. 1 (2005): 11-20.|
|↑30||Ebina, Kosuke, Kenrin Shi, Makoto Hirao, Shoichi Kaneshiro, Tokimitsu Morimoto, Kota Koizumi, Hideki Yoshikawa, and Jun Hashimoto. “Vitamin K2 administration is associated with decreased disease activity in patients with rheumatoid arthritis.” Modern rheumatology 23, no. 5 (2013): 1001-1007.|
|↑31||Cario-Toumaniantz, Chrystelle, Cédric Boularan, Leon J. Schurgers, Marie-Françoise Heymann, Martine Le Cunff, Jean Léger, Gervaise Loirand, and Pierre Pacaud. “Identification of differentially expressed genes in human varicose veins: involvement of matrix gla protein in extracellular matrix remodeling.” Journal of vascular research 44, no. 6 (2007): 444-459.|
|↑32||Hoffman, Richard. “Re: Saturated fat is not the major issue.” British Medical Journal (2013).|
|↑33||Gheduzzi, Dealba, Federica Boraldi, Giulia Annovi, Chiara Paolinelli DeVincenzi, Leon J. Schurgers, Cees Vermeer, Daniela Quaglino, and Ivonne Pasquali Ronchetti. “Matrix Gla protein is involved in elastic fiber calcification in the dermis of pseudoxanthoma elasticum patients.” Laboratory investigation 87, no. 10 (2007): 998.|
|↑34||Jiang, Qiujie, Qiaoli Li, Alix E. Grand-Pierre, Leon J. Schurgers, and Jouni Uitto. “Administration of vitamin K does not counteract the ectopic mineralization of connective tissues in Abcc6-/-mice, a model for pseudoxanthoma elasticum.” Cell Cycle 10, no. 4 (2011): 701-707.|
|↑35||Not Just Skin and Bones: Wrinkles Could Predict Women’s Bone Fracture Risk. Yale News.|