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Vitamin K2

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

written by Vin Kutty

comments 39 comments

vitamin k2

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.

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 can be deposited in soft tissues, in places other than your bones. *

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

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

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 promote heart health. 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 soft tissues like 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 support heart health

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 52% lower risk of calcium build up

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% improvement in heart health.*

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


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.

[Do not discontinue taking any prescription medication without talking to your doctor.]

How does Vitamin K2 work?

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 being deposited where it should not be.
  • Vitamin K2 is essential to activate this protein
  • If you are low in Vitamin K2, then this protein cannot do its job

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.

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.

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…

Photo credit.

*These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.


Join the conversation

  1. Hello!

    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?


    • 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.

      • 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.)


        • 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. 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.


    • 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. 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,

    • 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?


      • 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.

  4. 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?


    • 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

  5. 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.


    • 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.

  6. 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 ?



    • 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.

  7. Vin,

    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.



    • 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.

      • Vin,

        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 ?



        • 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!

          • 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.



            • 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.

  8. 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.

    • Not so sure that Factor X is vitamin K2… just because Chris Masterjohn says so does not make it so. This has never been confirmed. As it turns out, with modern testing from Vita K Labs in Netherlands, there is just a very small amount of K2 in butter in the form of MK-4, with butter oil having a bit more. No other MK’s present and a small amount of K1. There are many other suggestions regarding the origin of Factor X… and the Wulzen Factor.

      • Hi Aurjan – it’s possible that the old cod liver oils may have had more K2. New FCLO are made with pollock livers on well-run, USDA-inspected factory ships off Alaska – the filets go to McDonalds-type restaurants and the liver oil goes to supplements. I don’t expect huge amounts of K2 in pollock oils. The people Weston Price studied may have also had several sources of K2 and other fat soluble vitamins in their diets…they also ate organ meats.

        Masterjohn is usually right though…even though I don’t agree with him on everything.

  9. 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.

    • 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 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 grams per day. This has been proven wrong, even when fish oil is combined with aspirin.

      More here:

  10. 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. 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.

  12. Hi Doc – Neu5gc has been linked to inflammation. Connecting the dots all the way to cancer is more than what science currently supports. There is a tiny little bit in cow, and subsequently milk and cheese. Seafood and poultry do not have Neu5gc as it’s a mammalian molecule. So if you’re concerned and want to reduce beef and pork, considering increasing seafood and possible a little poultry. Grass-fed butter, eggs, fermented foods, and cheese are all still perfectly good sources of K2. As long as you don’t have allergies to these foods, you’re fine.

  13. Hi Julie – I cannot provide medical advice. Nor can I provide rationale or support for not following your doctor’s suggestions. Having said that, you may want to look into dietary sources of Vitamin K2 and feast away. There are a lot of good online sources for finding foods high in K2. I will also say that it is generally a bad idea to take high amount of Calcium or Vitamin D3 without other cofactors required for proper absorption. These include magnesium, Vit C, Vit K2, boron etc. I strongly suggest that you get these nutrients from food and rely only supplements when your diet lapses.

      • Hi
        Is the amount of 100mg of k2 a day safe for A fourteen year old ? And do
        I need to be concerned about the magnesium stearate in supplements? I’m from the UK so looking for a good k2 supplement


        • Hi Kerry – it is 100 mcg (micrograms), not mg (milligrams)…and yes, it is safe for a teenager to consume 100 mcg of K2 daily as a supplement.

          No, you absolutely DO NOT need to be concerned about magnesium stearate in supplements. Both Magnesium and stearic acid are both completely safe…magnesium is essential and stearic acid is a fat that’s found in virtually all animal foods – it is a neutral fat (no harm and no benefit). Magnesium stearate is used as a flow agent (powders need to flow into capsules) and there is not a single study that shows magnesium stearate is harmful to humans or animals. Our sister company, InnovixLabs has a good formula available on (they export supplements from the US to UK):

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