Vitamin K2: what is it? Why you absolutely need it and where to get it

Guest article by Kathy Mankofsky, Rd, LD.

All those calcium pills you’re taking could be a waste of money…or worse, could be hurting you. Find out how Vitamin K2 can help.

Vitamin K2 - where to find
Hard cheeses like Gouda are good sources of Vitamin K2


Calcium can prevent osteoporosis. Nothing new there.

But if we are all taking calcium, why are our bones still brittle?

Bones are mostly calcium, so all those calcium pills should help, right?

Not necessarily.

Recently, some studies (like this one and this) are showing that higher calcium intake through supplements can significantly increase heart attacks. A 139% increase in risk was noted in one study.

This happens because calcium builds up in the blood vessels causing blockage.

Why is calcium blocking arteries and causing heart attacks instead of going into your bones?

The answer is that we are not getting enough Vitamin K2.

Vitamin K2 helps calcium to go to the right places. It directs calcium to go into your bones and teeth instead of your arteries.

When your diet is low in Vitamin K2, calcium builds up in the arteries and valves. It also attaches to plaque. This can cause hardening of the arteries, heart attacks and strokes.

While it seems like bone loss and heart disease are two totally different problems, they are related because they both depend on adequate levels of Vitamin K2.

You’ve probably heard of Vitamin K…

The one that’s in green leafy veggies and helps in blood clotting. It turns out there’s more than one type of Vitamin K.

This one is called Vitamin K1 and it doesn’t work on your bones and it does not prevent heart disease. Vitamin K1 is involved in blood clotting.

[If you are on Coumadin/Warfarin, talk to your doctor before taking Vitamin K supplements.]

Vitamin K2 and your heart

Vitamin K2 tells calcium to go into bones and not into blood vessels.

There are a few types of K2, but these are the important ones:

  1. MK-4 (Menaquinone-4)
    • Found in animal based foods such as meat, chicken, cheese, egg yolks and butter
    • Higher amounts of K2 are found in grass fed versions of these foods. (It turns out that animals can convert grass to Vitamin K2)
  2. MK-7 (Menaquinone-7)
    • Found mainly in a popular Japanese food called Natto. Natto is derived from bacterial fermentation of soybeans.
    • Also found in other fermented foods such as sauerkraut.

Vitamin K2 is a fat soluble vitamin. It’s usually found in the fatty part of foods. You have to have some fat in your meals for Vitamin K2 to be absorbed. If your meals are all low in fat, you won’t absorb much Vitamin K2.

Vitamin K2 and Probiotics

Vitamin K1 can be converted to Vitamin K2 by the bacteria in your gut. But this doesn’t always work as intended because of antibiotic use and poor gut health/diet.

This makes eating foods containing K2 even more critical.

Studies show Vitamin K2 may prevent heart disease

Vitamin K2 - what is it, why you need it and where to get it

In the Rotterdam study 4807 subjects were studied for 7 years. Those with the highest levels of Vitamin K2:

  • Had 57% lower risk of dying from heart disease
  • Had 26% reduction in dying from all causes
  • Had 52% lower risk of calcium build up

The study found that Vitamin K2 protects against heart disease by inhibiting calcium hardening in the arteries.

The Epic study followed over 16,000 women for 8 years. This study found that for every additional 10 mcg (micrograms) of Vitamin K2 consumed there is a 9% reduction in the risk of developing heart disease.

This study shows a high intake of Vitamin K2 reversed calcium build up in the arteries in rats. (Proof that the same happens in humans is still building.)

Another study showed the higher the Vitamin K2 intake the less coronary calcification there was.

Do I still need Vitamin K2 if I’m already taking statin drugs for lowering cholesterol?

Yes. Statin drugs won’t break up the calcium plaque.

Research shows that lipid-lowering drugs such as statins, have failed to reverse existing arterial calcification.

Actually, some studies (this one and this) show that using statin drugs increases calcium deposits in your arteries. These observational studies don’t prove that statins cause increased calcium deposits.  It could be that since Vitamin K2 is found in animal fats and animal fats are often removed from the diets of those on statin drugs. So the root cause could be Vitamin K2 deficiency rather than taking statin drugs.

Warfarin and Vitamin K

Blood thinners like Warfarin can save lives. But few people realize that Warfarin works by inhibiting the effect of Vitamin K.

Rats given Warfarin quickly build up calcium blockages. The same rats, if given high levels of Vitamin K2, had 37% less calcification. This study has not been duplicated in humans. [Do not discontinue taking any prescription medication without talking to your doctor.]

Can Omega-3 reduce calcium plaque?

No – there is no evidence of this.

Omega 3-fish oil slows the progression of plaque. See this, this and this.

EPA Omega-3 makes plaque more stable. This decreases the risk of plaque rupture.

How does Vitamin K2 prevent heart disease?

It activates a protein called matrix GLA protein (MGP).

What is matrix GLA protein?

  • It is a protein that prevents calcium crystals (bone cells) from forming in the arteries
  • Vitamin K2 is essential to activate this protein
  • If you are low in Vitamin K2, then this protein cannot do its job
  • Calcium can harden in the arteries in the same way that calcium hardens in the bones.

That’s why researchers have found actual bone cells in the blood vessel walls.

Without enough Vitamin K2 bones form in the wrong places. Like your heart.

Indicators of low Vitamin K2 status

  • Heart disease
  • Osteoporosis
  • Low-fat diets
  • Antibiotic use
  • Not eating fermented foods like Natto, sauerkraut etc.

There are no simple, inexpensive tests for measuring your Vitamin K2 status. So this may be a case where supplementation is appropriate.

Since Vitamin K2 is a fat-soluble vitamin, it is easier to find in fatty or animal-based foods like egg yolk, hard cheese and butter. K2 deficiency is often an unintended result of going on low-fat diets.

Fermented foods like Natto are unavailable to most Americans. And when introduced to Natto, most Americans find it offensively stinky and slimy. Regular consumption of fermented vegetables like sauerkraut or beet kvaas is rare, even among vegans.

A note to vegans:

Vegans who take extra calcium pills to make up for not getting calcium from dairy may be headed for trouble…especially if you do not eat fermented veggies or Natto. You’d have to eat a pound of sauerkraut a week to get enough Vitamin K2. But there’s good news for vegans in part 2 of this blog.

Back to calcium supplements…

TV commercials for calcium supplements would have you believe that one calcium pill per day will fix your osteoporosis for good. The truth is a bit more complex. You need a lot more than just calcium to cure osteoporosis. You need Vitamins K2, D3, magnesium and a long list of nutrients from a variety of whole foods.

Taking those big calcium pills may not cure your bone problems…instead, it may have you rushing to the cardiologist.

In part 2 we will discuss:

  • Role of Vitamin K2 in keeping our bones strong and healthy
  • How much you need
  • Where to get it

Till next time…

DISCLAIMER: This website is for your education and general health information only. The ideas and suggestions contained on this website are not to be used as a substitute for medical advice, diagnosis or treatment from your doctor for any health condition or problem. Users of this website should not rely on information provided on this website for their own health problems. Any questions regarding your own health should be addressed to your own physician.

Fish Oil Labels Kathy Mankofsky RD, LD is a registered and licensed dietitian. She has studied Omega-3s extensively. She lives in St. Louis, Missouri.

Bolland, M.J. et al. Effect of calcium supplements on risk of myocardial infarction and cardiovascular events: meta-analysis BMJ: 2010 July 29;341:c3691.

Bolland, M.J. et al. Calcium supplements with or without vitamin D and risk of cardiovascular events: reanalysis of the Women’s Health Initiative limited access dataset and meta-analysis. BMJ. 2011 Apr 19;342:d2040

Rheaume- Bleue, Kate. Vitamin K2 and the Calcium Paradox : How a Little-Known Vitamin Could Save Your Life, Mississauga, Ontario. John Wiley and Sons Canada, Ltd., 2012.

Geleijnse, J.M. et al Dietary Intake of Menaquinone Is Associated with a Reduced Risk of Coronary Heart Disease: The Rotterdam Study. J. Nutr. 2004August;134:3100-3105.

G.C.M. Gast. Et al. A high menaquinone intake reduces the incidence of coronary heart disease. Nutrition, Metabolism & Cardiovascular Diseases (2008) xx, 1-7 .

Schurgers, L. J. et al.Regression of warfarin-induced medial elastocalcinosis by high intake of vitamin K in rats.Blood.2007 109:2823-2831.

Beulens, J.W. et al. High dietary menaquinone intake is associated with reduced coronary calcification. Atherosclerosis. 2009 Apr;203(2):489-93.

Raggi, P. et al. Aggressive versus moderate lipid-lowering therapy in hypercholesterolemic postmenopausal women: Beyond Endorsed Lipid Lowering with EBT Scanning (BELLES). Circulation. 2005 Jul 26;112(4):563-71.

Nakazato, R. et al. Statins use and coronary artery plaque composition: results from the International Multicenter CONFIRM Registry. Atherosclerosis. 2012 Nov;225(1):148-53.

Saremi, A. et al. Progression of vascular calcification is increased with statin use in the Veterans Affairs Diabetes Trial (VADT). Diabetes Care. 2012 Nov;35(11):2390-2.

Dimitrow PP. et al. Pleiotropic, cardioprotective effects of omega-3 polyunsaturated fatty acids. Mini Rev Med Chem. 2009 Aug;9(9):1030-9.

Connor, SL. Et al.Are fish oils beneficial in the prevention and treatment of coronary artery disease? Am J Clin Nutr. 1997 Oct;66(4 Suppl):1020S-1031S

F. et al. Association of n-3 polyunsaturated fatty acids with stability of atherosclerotic plaques: a randomised controlled trial. Lancet. 2003 Feb 8;361(9356):477-85.

Cawood, AL, et al. Eicosapentaenoic acid (EPA) from highly concentrated n-3 fatty acid ethyl esters is incorporated into advanced atherosclerotic plaques and higher plaque EPA is associated with decreased plaque inflammation and increased stability. Atherosclerosis. 2010 Sep;212(1):252-9.

Kanai, S. et al. Eicosapentaenoic acid reduces warfarin-induced arterial calcification in rats. Atherosclerosis. 2011 Mar;215(1):43-51

Masayuki Ueeda, et al. Serum N-3 Polyunsaturated Fatty Acid Levels Correlate With the Extent of Coronary Plaques and Calcifications in Patients With Acute Myocardial Infarction. Circ J 2008; 72:1836 – 1843.

Reidar Wallin. Et al. Effects of the Blood Coagulation Vitamin K as an Inhibitor of Arterial Calcification. Thromb Res. 2008; 122(3): 411–417.

Photo credit.


  1. Gail says


    My head is overflowing with all the information in it after much research toward finding a fish oil to take (after having taken krill for a while…). I’ve appreciated finding this website and all I’ve learned, particularly from the blog comments section. Appreciate Mr. Kutty’s knowledge and willingness to share it.

    I would prefer a liquid fish oil product. I really liked what I read about Omapure (very concentrated), and would order, but it’s in the ethyl ester form, which I think I do not want. Do you agree on that point?

    So it got down to good old Carlson or the Nordic Naturals. I don’t believe Carlson is part of the IFOS program – not sure if that should be a deal breaker?? If my math is right, these two are pretty close in what they deliver and cost.

    Last minute entry is A-M B-Well, which is checked by IFOS. ( Same amt of EPA and DHA as Nordic Ultimate, but this costs even more. Too bad – the thing I liked about the Omapure and the A-M B-Well is smaller bottles -seems better for freshness issues.

    Any thoughts to push me in a direction?


    • Vin Kutty says

      Hi Gail – glad you like the information on this site.

      Going back to fish oil after krill is a good thing. Liquid fish oils are good way to ingest a lot of Omega-3 in short order. If you can handle the taste and are prepared to treat the oil delicately – refrigeration after opening etc.

      Omapure seems like a good brand. Their softgels are not extremely concentrated, but mid to upper-mid grade. The whole ethyl ester (EE) and triglyceride (TG) thing is completely blown out of proportion by people marketing TG fish oils. You’d think if you took an EE fish oil that you’d simply keel over. Nonsense. If you take EE fish oil with food, the difference is absorption is virtually gone. More here:

      There are over 20,000 research papers done on Omega-3. And almost all of them were done using EE oils.

      I prefer Nordic Naturals over Carlsons. But I like Carlsons enough that I gave my wife one of their DHA pills when she was pregnant. I’d pass on A-M-B Well even though it is IFOS tested when compared to Nordic.

      • Gail says

        Thanks Mr Kutty.

        So…if you were choosing amongst these 3 liquid products, what would be your 1st, 2nd and 3rd choices? – Omapure, Carlson, Nordic Naturals. (I noticed that the Omapure EPA:DHA ratio is about 5:2; the others are more like 3:2. Not sure how much I need to think about the ratio.)


        • Vin Kutty says

          Hi Gail – Nordic, Carlson, Omapure would be my order of choice. But I like Omapure’s ratio the best. I’d still go with Nordic.

  2. Gail says

    That’s interesting that you would choose Nordic even though Omapure has your more preferred ratio, and given that the EE part of Omapure is not an issue, and it’s checked by IFOS.


    • Vin Kutty says

      Hi Gail – that’s because it is a liquid fish oil. If it were a capsule, I would go with the choices I did. Liquid fish oil is a delicate creature and the oil needs to be handled like a just so. I chose Nordic and Carlsons because they have a longer history of handling liquid oils. With enough time and proof, I could be convinced to change my choices, but not yet.

  3. Gail says

    Hello Vin,

    OK – I see your reasoning now.

    You’ve been most generous with your time and expertise, and it was very helpful. I appreciate the direction you’ve given me.

    Thanks much,

  4. Gail says


    So sorry – I thought I was done! But I remembered something important. My daughter (age 31) has familial hypercholesterolemia. She is normally on a statin, but has had 2 babies in the last couple years and still breastfeeding the 2nd, and of course, off her statin for now. I assume she will go back on it. She’s been taking fish oil, a NOW brand one on the advice of her cardiologist. She is open to changing brands. As long as she is pregnant or nursing, she needs the EPA:DHA ratio to be weighted more to the DHA side, right? What kind of ratio should she be looking for, and can you recommend a product?

    Thanks ever so much,

      • Gail says

        Do the total grams you take change if she is going to switch to the DHA mini gels? Trying to figure how much to tell her to take. She’s has no other health issues than the familial hypercholesterolemia.

        I think she will breast feed a few more months then wean, at which point he will try the Nordic or Carlson liquid. Unless she gets pregnant! At which point I think she would go back on the mini-gels, right?


        • Vin Kutty says

          Hi Gail – she should aim for 1000 mg DHA per day mostly for the baby and 1000 mg EPA per day for her. Omega-3 needs go up dramatically in the third trimester but 1000 mg DHA ought to be enough for then too.

  5. RWM says

    Hi, Vin and Kathy.

    In a nutshell, what is the difference between MK-4 and MK-7? What does MK-4 do that MK-7 doesn’t do, and vice versa? Which is preferable, MK-4 or MK-7, and for what reasons? Which is more expensive, MK-4 or MK-7? If you had to choose, which would you go with, MK-4 or MK-7, and why?


    • Vin Kutty says

      Hi RWM – I will give you my thoughts and Kathy may add hers later.

      They are slightly different molecules. We don’t know much about either – actually what we know is the ‘tip of the iceberg.’ It is HIGHLY unlikely that we only need one of them and HIGHLY unlikely that one can do everything the other can. While they both keep arteries clear and bones healthy it is interesting to note that brain and pancreas store more MK-4 while the liver has more MK-7. Why? We don’t know yet. To me, this suggests they may have different functions as well.

      Here is a study from Japan that shows MK-4 does things that K1 and MK-7 do not: A Dutch study recently suggested that MK-7 and the longer MKs, (yes, they go all the way to MK-14 or so) are more responsible for heart health benefits.

      From what I know and have read, it would be foolish to choose one over the other. Given widespread antibiotic use, lack of grass-fed animals in our diet and lack of fermented foods, it would be a good idea to supplement both MK-4 and MK-7. I take both – I’d never take either or. I also take good care of my gut and the bacteria that reside within, eat only grass-fed meats, eat hard cheeses and fermented foods to get my other MKs that are not present in supplements.

      There is a lot of ‘marketing BS’, mostly spread by supplement companies that sell MK-7 that says ‘MK-7 stays in your blood for much longer, therefore it is better and all that you need.‘ That’s self-serving bullshit. Short half-life of MK-4 does not mean pharmacodynamics of MK-4 are weak.

      OmegaVia does not make or market K2 supplements (at least not yet!) but I take the LifeExtension product and I buy it for loved ones who cannot afford to.

      – Vin Kutty

  6. RWM says

    Vin, I’d be curious to know whether the bio-availability of a supplement can be increased either through the addition of nutrients or some kind of molecular or other process. Are there any companies doing it, and if so, which ones? How effective is it?

    I’m posting on this thread because I believe that phospholipids in krill oil (which are molecularly bonded to triglycerides in krill oil), increases its bio-availability, and I’m curious if this process can be replicated in the lab.

    BTW, it might be helpful if an email notification can be sent by OmegaVia alerting the sender that a response to an inquiry has been posted by your or Kathy.

    Also, if you can do it, I’d like to see some supplementation to your response to my previous inquiry about MK-4/MK-7.

    Thanks, as always.


    • Vin Kutty says

      Hi RWM – the bio-availability issue, as it applies to Omega-3, is done with phospholipid-bonding of Omega-3. That’s what krill oil is, as you mentioned. Krill Omega-3 is almost twice as absorbed as fish oil Omega-3. Well, the exact number is about 1.6 times better. But that’s about as good as it gets. The trick to increasing absorption of fats and fatty nutrients like fish oil, Vit D, A, E, K etc is to take it with a meal that contains a generous amount of fats. The fact that people are afraid of fats is unfortunate and self-defeating.

      There are companies like Jarrow that sell a phospholipid bonded fish oil. It’s a fish oil that’s re-structured to look like krill oil and act like krill oil. I say, why not just take krill oil? They claim better absorption than krill oil. I need to see more data.

      Will get with computer folks – it was set to alert you when I/Kathy respond to your comment.

  7. DPK says

    Hi Vin,

    I take Pure Encapsulations magnesium glycinate for calcium absorption. Why is glycinate more expensive than citrate, by 50% on Amazon. Is this a bio-availability issue and citrate is not as readily absorbed as glycinate ? What brand/form do you use ?



    • Vin Kutty says

      Hi DPK – yes, glycinate is more expensive because of the production process. And yes, it is also better absorbed. But Citrate is not that bad. It is mag oxide that is useless. I take Jigsaw health Magnesium.

  8. DPK says


    Wow, that was fast ! I’m grateful that you take the time to answer EVERY comment posted here. I’ve learned so much and have already started to incorporate into my diet some of the useful info that you’ve shared, more omega-3, less omega-6, etc.

    The magnesium you’re using, Jigsaw magnesium with SRT also has active form of Vitamin B9 (Folic Acid) and Vitamin B6 (P5P). Are these necessary for absorption or are you also addressing other specific issues ? Is magnesium by itself, glycinate, malate or citrate, without the added vit B’s, adequate to aid calcium absorption ? Of course I will add K2 to the calcium also.



    • Vin Kutty says

      Hi DPK – thank you. I like the B-vitamins as a back up on days when I’ve not eaten enough eggs/liver etc. Their formula is great for mood support. Technically, I suppose they add the B-Vits and time release so they can charge a lot more for regular ol magnesium, but I don’t mind. It’s good quality stuff. The Bs are not essential for absorption. Magnesium by itself will help but you need a whole host of ingredients starting with D, Ks and Magnesium. Eating your way to better bone health is far more fun and better than pill-ing it.

      • DPK says


        Calcium/D3/vit K are taken together with food. What about magnesium ? I’ve read that it can be taken with food or without since it’s water-soluble, but preferably in between meals when there’s more stomach acid for better absorption.

        Since my 8 year-old son can’t swallow pills, can I break open the vit K capsule and mix it with milk ? Can I also dissolve the magnesium tablet in milk ?



        • Vin Kutty says

          Hi DPK – you should be fine taking magnesium at any time. I take mine with food.

          With kids, I would not feel comfortable with Vit K supplements. Not that they don’t need it! If you must, do it once a week or so. Not every day. You’re better off giving your child hard cheeses made from grass-fed cows and meats from grass-red cows to contribute some Vit K.

          Get Natural Calm magnesium powder. It is made to be dissolved into water. Much better than breaking pills. Also lots of veggies!

          • DPK says

            Thanks so much for the recommendation. Natural Calm has several flavors that are sweetened with stevia. Is this something safe to consume ? There’s no quantity of stevia listed per serving size of 325mg/2 teaspoons. He’s 8 so I will only give him 1 teaspoon/day as recommended. He also eats lots of veggies so hopefully this will take care of his magnesium needs.

            The GNC store near me doesn’t carry the un-flavored powder. I can order the plain version on-line but just thought I’d run out and grab a bottle on my next errand and save on shipping.



          • Vin Kutty says

            Hi DPK – Stevia is probably OK. A lot better than sugar or artificial sweeteners from what I’ve seen. But I prefer the unflavored, unsweetened stuff, so I can add to whatever liquid I want.

  9. Randal Romero says

    In his clinical trials on tooth decay, Dr Weston Price achieved the best results when he gave children vitamin D from cod liver oil together with what he termed fat-soluble “Activator X” found in concentrated butter oil from grass-fed cows. We now know that Activator X is vitamin K2.

  10. Aaron McKay says

    Have you tied Natto? Really nasty tasting stuff. Its an acquired taste I guess. I’ve only seen it served in Japan where it is a popular breakfast item. A lot of Japanese folks don’t like it either. Its worse than eating canned peas but its true, that Natto is high in MK-7.

    Vitamin K also helps with proper blood clotting. This is why a vitamin K shot is given to babies moments after birth. It may even help folks who already have a tendency to bleed and not clot if they are cut or are getting ready to have surgery. It seems to me that with so many things that thin our blood (pain relievers, fish oil, etc…) Vitamin K is a good idea for a lot of people to take.

    • Vin Kutty says

      Hi Aaron – yes, I tried Natto while in Asia last year. Ugh. I tried it just to see how it tasted and that was enough. An option for Americans is Jarlsberg cheese. It is very high in MK-9 of all things. We don’t know a lot about MK-9, but it’s a fair assumption that it has similar properties as MK-7 and MK-4.

      The Vitamin K you mention in relation to blood clotting is K1 or phylloquinone. Totally different beast. K1 is easy to get from green veggies and the body recycles it, in other words, it is not easy to go deficient in it. Since newborns have not been eating green veggies, it makes sense to give them a K1 shot.

      The risk of not having enough K is from K2 deficiency causing unintended calcium deposition in the body – like calcium getting deposited in your arteries and blocking it versus the bleeding risk from not enough K1. If you’re K2 deficient, your body has no clue what to do with all those calcium supplements you’re taking. I tried to get my elderly mother to ease off on her calcium pills, but she just looked at me funny. So I got her a lifetime supply of K2 pills. I highly recommend that you pick up a copy of this book – easy read:

      It is somewhat of a myth that Omega-3 causes bleeding at doses up to 3 or 4 grams per day. This has been proven wrong, even when fish oil is combined with aspirin.

      More here:

    • Vin Kutty says

      Hi Nicola – this is a medical question that should be directed to your doctor. There are a couple of types of hyperparathyroidism and in some cases, it could be a result of Vitamin D deficiency. I suggest working with a functional or integrative doctor and a nutritionist to get to the root cause or rule out possibly minor things like Vit D deficiency.

  11. Nicki says

    Thanks for your fundamental information. I suffer from several (autoimmune) diseases, have to take hydrocortisone lifelong among other things and so I secondary got osteoporosis. Aside from other supplements I take 5000 i.E. of vitamin D3 but I am always doubtful for the proper dosage of vitamin K2 (actually between 100 and 200 mcg). Is there any mathematical relation for vit D3 and vit K2 or any other advice in terms of vit K2 quantity?

    • Vin Kutty, MS says

      Hi Nicki – your email is perfectly timed. 75% of autoimmune issues are a result of the environment (food/lifestyle/environment) and only 25% is genetic. There is a free online event going on this week with several highly respected speakers – check it out: I highly recommend you listen to all the lectures.

      I try not to have very strict ratios for D to K2. But for now, 100 to 200 mcg of K2 is great. And 5000 IU of Vit D3 every day, well, that may be enough or too much – no way to tell unless you take a blood test.

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