What are the best sources of vitamin K?

I have read in a magazine that there are several types of vitamin K. According to the article, Vitamin K1 is found in vegetables. Vitamin K2 mk7 is found in meat, fish and eggs. The article also said that Vitamin K1 is stored in the liver for only one hour, time not enough to perform all its tasks. On the contrary, vitamin k2 mk7 would stay in the liver for the whole day. So my question is: should vegetarians take supplements of vitamin k2 mk7 (created from natto)?

vjimener / Originally posted below Better than green tea?


Not sure what magazine you were reading, but the scientific consensus is that either one (phylloquinone or menaquinone, formerly K1 and K2) is fine for maintaining human vitamin K status. The recommended intake is about 100 mcg. A half cup of kale? >500. No need for natto; just eat your greens.

In fact dark green leafies are so packed with vitamin K that if you’re on the drug coumadin (warfarin), a drug that works by poisoning vitamin K metabolism, you have to closely work with your physician to titrate the dose to your greens intake so as to not undermine the drug’s effectiveness!

Learn more about the wonders of greens in my 25 videos (like Eating Green to Prevent Cancer) and kale in particular in videos such as Smoking Versus Kale Juice and Kale and the Immune System.

Image credit: ilovemypit / Flickr

  • Tony

    Isn’t vitamin K1 distinct from K2. K1 plays an important role in coagulation. K2 plays a role in directing where calcium gets stored. Too much calcium in the blood can cause calcification, K2 helps direct the calcium to the bones. If that is true, don’t we need to satisfy our requirements for K2 specifically? Sounds like we would need to be getting some natto after all.

    • Kert

      No need to eat Natto if you don’t want (I’ve tried it and it’s yuck). Just have lots of greens, e.g. kale. Vitamin K1 gets converted into vitamin K2 in your body. The conversion occurs with 15% efficiency, but because green are so packed with vitamin K1, you’ll end up getting enough.

  • adawe

    mk4 isn’t same as mk7 either. both are k2, but different forms

  • colonyofcells delacruz

    I like natto bec it is fermented and the vitamin k2 from natto is a nice bonus. I have been able to find low salt natto bec I don’t like any added salt. I have already decided to get rid of miso since I cannot find low salt miso.

  • Sharon

    I was reading K2 and Calcium Paradox and it indicates the only non-animal source of K2 is natto (which I don’t like). It also says K2 is not the same vitamin as K1.. ie. K2 prevents atherosclerosis, diabetes 2, cancer, and osteoporosis, etc, whereas K1 only helps with blood clotting. I tried researching on internet if this is true or quackery.. I don’t believe everything I read.. but so far have not found information on sites I would consider trustworthy.

    • Kert

      They are different, but you don’t need to eat K2. Eating enough K1 will result in the K1 being converted to K2. Bottom line is get enough greens. Drink green smoothies, e.g. blend some kale with banana and chia seeds.

  • Jeremy Nagel

    I think the research that Michael cited is out of date (published in 2009). I would suggest people read the review article “The role of menaquinones (vitamin K2) in human health” published in the Cambridge Journal of Nutrition in 2013. It states that Vitamin K2 has an important and distinct role in bone health. It also provides evidence that absorption of K2 produced by intestinal bacteria is very inefficient (because the K2 producing bacteria are located in the colon whereas K2 absorption happens in the small intestine). Therefore it recommends that everyone take a form of K2 every day, either from natto, animal products or supplements. (I’ve been taking a vegan K2 supplement sold by VitaCost.com).


    • Darryl

      Menadione (K2) is a metabolite of oral phylloquinone (K1), though only 5-25% is converted. In rats, at least, this conversion isn’t dependent on gut bacteria.

      My understanding, so far, is that a couple cups of greens a day is enough for most requirements, but in as yet unproven therapies (like reducing vacular calcification), high, supplemental doses of free K2, preferably in oil emulsion, may be required.

    • sf_jeff

      I am really surprised to see someone claim that the bacteria in the colon are different species than what you find in the intestines. Doesn’t pass the smell test.

  • Luc

    I strongly believe that vegan it is only possible to take profit from a vegan diet , rich in many useful nutrients, if we don’t turn a blind eye towards the downsides of not eating meat. Such as Vit D, Vit B12 , possibly Vitamine K(2) and who knows are there more …

    Vegans seem to have so much benefits , yet , no higher life expectancy proves that we are still missing some pieces of the puzzle, wood you agree to that ?
    So I am looking beyond what is served to me today.
    Maybe I found something here:

    I (53) have been taking Natto for a few weeks now and , waaw
    Before , being a vegan for over a year now, I can solve some of my healthissues but found it hard to make my bloodpressure move just a little bit…..

    Eating Natto , my bloodpressure 140/90 (150/100without medication ) just dropped to 110/80 (95/60 by moments). Waaw , this is not food , just a table spoon every day does more then medication. I am impressed. Yet it is not a structural solution to my high blood pressure.When I stop eating for a few days my BP goes up again.

    As for the longterm effects of other components in Natto , they remain to be seen, I am hopeful however to reduce some calcification in my arteries by eating Natto. More and more research from the past 10 years starts to indicate that it might be possible.

    K1(vegetables) and K2(from Natto) may have the same value in terms of directing calcium form our arteries towards our bones, K2 stays in our blood for days whereas K1 seems to be eliminated after few hours , hence we should eat tonnes of green leaves to keep up a certain level of K1 in our blood, while a tablespoon of Natto every day can do the trick 10 times better.

    (btw, I am not producer or selling Natto:) )

    • 718Ken

      Dr. William Li says one can get high amounts of K2 from Natto but most westerners hate it. He says you can get large amounts of K2 from Gouda, Ementhal cheese,l Jarlsberg and Edam cheese. He says it helps prevent cancer, prevents heart disease, by keeping arteries flexible, helps deposit Calcium in bones instead of blood vessels. I am hoping that Dr. Gregor might comment on this.

    • Arjan den Hollander.

      Same story here, impressive research and results.

      I throw a chuck of frozen natto through kale/red cabbage/spinach vegetable shakes,
      as long as there are some peanuts in there and or strawberries it gets to be quite tasty to me.
      These two ingredients really transform the blend from an atrocity into something much much better ^^.

    • dorange

      Vitamin K2 is known to lower blood pressure, hense your results with natto!

    • lemonhead

      I actually like natto now. Not the first time I ate it, I had to choke it down. The second time it was just meh. Now I like it. I’ve found that however I eat it, it is best with a lot of spicy mustard (Coleman’s is a good brand), I used to eat it with rice, not I make a soup out of it with miso and mustard and sometimes ginger. I know I feel great when I eat it regularly. Natto contains spermidine and another of Dr. Greger’s videos cited health issues associated with spermidine; I had previously thought that spermidine was good for health since it promotes autophagy – taking out the cellular trash. So I am wondering if natto really is overall good for health or not. Many Japanese eat it for breakfast (and I understand many eat it because it is thought to be healthful, not because they like it) and they have good life expectancy, but this is just one food in a diet that is quite different overall from Western diets.

      I wish Dr. Greger would do a ‘natto – good or bad’ video.

  • Alain Lachance
    • Selina

      Very interesting study, I wonder if there are more studies like this showing that vitamin K2 might have more benefits than regular K vitamin?

      Dr Greger, I would much appreciate if you would dig further into this whole K2 business. There are a lot of claims out there about this “super vitamin”.

      • Arjan den Hollander.

        Google Cees Vermneer, he has devoted his career researching this vitamin.

        This should give a good impression of his involvement withing the studies involving K family of vitamins.

        I’ll be eating natto till the day I die. ;)

    • Billy

      This study is probably only applicable to omnivores- they’re already at risk for heart disease, and were no doubt the subjects of the study. Phylloquinone in a vegan diet may be adequate for the low-risk vegan, especially when you factor in the menaquinone produced by bacteria in our small intestines. http://www.ncbi.nlm.nih.gov/pubmed/1492156

  • Joe Tilman

    Any comment about the fact that natto is also replete with B12?

  • folk_singer

    Your assessment of vitamin K2 is wrong. Read Wikipedia on K2 and the “Calcium Paradox”. If you want to go vegan, you must supplement K2, zinc, taurine and B-12. Your vegan bias is making you look ridiculous. I’ve seen you dismissed as a vegan fanatic. I agree with most of your assessments, but not that we get enough K2 from K1 and vegetables. Calcium from any source without K2 can land in our arteries instead of our bones. Its what’s responsible for “hardening of the arteries” and high blood pressure because the walls of the arteries become less elastic. Start posting results from European publications and knock off your America only bias. Read the commentators on this topic.

    • AlwaysWorking

      You know what you are talking about.

      I’m not sure about taurine yet (still doing my own research, I know it is made in our bodies from cysteine which we can get from plant sources like soy, but maybe we don’t get enough or it isn’t converted enough?), but it would explain why a lot of vegans I know go grey early.

      Add vitamin D to your list and that should be all the supplements you need to take.

      I believe we should always look at the evolutionary science when it comes to our diets. While we are related to chimps the most, we did come from gorillas (technically it was a gorilla ancestor that no longer exists, but you get the point). Gorillas eat bugs like termites (chimps eat termites too, but they also eat meat).

      And what do termites have? B12 and K2 in their guts (they have special bacteria to break down wood).

      And bugs have a high mineral content. For example, mealworms are high in zinc (take that with a grain of salt, finding reliable nutrition information on bugs is hard, even with the internet). And vegans tend to be deficient in minerals like zinc, calcium, and iron. But of the three, I believe zinc is the only one of real concern.

      And of course we get our vitamin D from being in the sun. And maybe taurine from insects? I’m not sure.

      So this solves the mystery behind almost all the deficiencies in a vegan diet (if you are wondering about omega-3, I’ve seen some recent studies saying vegans have enough EPA and DHA in their blood from only consuming ALA sources and gorillas eat dark greens, which have some omega-3, throughout the day. We definitely need more research on humans, but gorillas seem to do just fine on ALA. So unless you eat dark greens 24/7, eat your flax at a minimum).

      So it is either bugs or supplements.

      Dr. Greger, we’ve seen your videos on bugs. We know you think they are a good source of nutrition. But please do a video on the following topics and let us know of any studies you think we are missing:
      Vitamin K2
      Zinc (please do an update saying if we can get enough from just vegan whole foods, because I don’t see the math working out, at least not for men)

      Still, I’m very grateful for all the hard work you’ve done. Thank you Dr. Greger (and his volunteers)!!!

      • AlwaysWorking

        I spoke too soon on the zinc issue. It is possible, but you do have to eat a lot (which I do).

        Per VeganHealth.org, you need 11 mg for a male and 8 for a female. Before you say vegans absorb less, the study cited in the link above showed vegans having pretty much the same levels as meat eaters.

        Pulling data from Nutritiondata.Self.com, I put my usual meals to the test

        4 cups of brown rice (cooked): 4.8 mg
        1 cup of black beans (cooked): 1.9 mg

        Salad (ignored)
        Apple with 2 TBS of peanut butter: 0.9 mg

        1 cup Oatmeal (cooked): 2.3 mg
        1 cup sweet potatoes: 0.6 mg

        That gets me to 10.5 mg. When you add all the other misc stuff I also eat (mostly fruit and nuts), I’m sure I get the other 0.5 mg.

      • folk_singer

        AlwaysWorking -> A thought provoking response. What Dr Greger has on vitamin K was the scientific consensus as of 2008. It needs updating. Taurine acts as a calcium channel blocker, which is an important function, since calcium build-up is toxic inside the cell, hence the need for magnesium to keep it in solution in the blood stream. My research shows calcium metabolism to be the determiner of aging. It is used to patch up our organs until the organs can no longer function.

        My multi-vitamin has 30mg of zinc which is 2X the RDA. As you note, vitamin D3 is extremely important in its role in calcium metabolism. It gets calcium from the gut into the blood stream. K2 takes over from there. More D3 is being added to multi-vitamins. I hope to see more references to Cochrane meta-studies which much more weight than selecting individual studies to highlight. As far as supplements – a multi-vitamin, vitamin D3 in the winter and omega-3s from fish oil or algae should suffice.

    • noexitlovenow

      Y’all may have a point, but the fact is that a whole foods plant based
      diet is the best defense against heart disease. Perhaps you want to
      tweak it by supplementing with various nutrients, but not doing so is
      hardly a horrible oversight as no matter what it has been shown that a
      whole foods plant based diet without supplementation is already superior
      against heart disease. The End.

  • Paul Spring


    Why isn’t this being addressed and why is such an outdated take on vitamin K being presented? It is so important to not only point out the strengths of a vegan diet but the weaknesses.

    It appears that there is more recent info on the CVD impacts of vitamin K2. I’ve been on a very low fat WFPB vegan diet for 2 years yet my CT Calcium Score increased from 152 to 221 event though my LDL is 70, HDL 43. Clearly there are other factors at play. You rarely mention LDL particle size which may be a more important indictor than LDL-C. Vitamin K2 may prove to be as crucial for vegans as B12 since only poorly absorbed K1 is present in the copious leafy greens I eat. Please address these head on.

  • vkat79

    Hello, dear community!

    In wikipedia, it says that cooked collard greens contain more Vitamin K(1) than raw collard greens. Why is that so?

    Thank you!

  • Nimce

    Hello everyone!
    I read more and more articles saying Vitamin K2 is critical for health and that our body is not producing enough of it.
    Is that true? do I need to supplement with Vitamin K2?

    • Joseph Gonzales R.D.

      Nope. Please see above.

      • Micki Jacobs

        Nope. Please see my comments. It may be that a wide variety of diets offer K repletion, but it means that anyone consuming only veggies better eat a lot of them, eat them with a fat (to make for bile to allow absorption), and either cook or juice them and they should seriously consider fermenting some.
        Instead of the incorrect assessments of dietary fats where we characterize their bonds (saturated, unsaturated, monosaturated, etc), we SHOULD ask how they affect vitamin K and vitamin K actions.
        Thus, olive oil is a highly bioavailable vitamin K1 (as are canola and soy, but since they are usually GM they have glyphosate which is an antibiotic that impairs gut bacteria, which DO contribute a little to our vitamin K status).
        dK, however, will impair vitamin K actions and it is biomarked by trans fatty acids. Trans fats are NOT the cause of CVD, but they lead to it by impairing vitamin K actions which ARE essential to heart health.
        Saturated fats SHOULD make for proper vitamin K actions if they are from animals which have MK-4 which has about the same life as K1. Only we feed animals weird things and have fouled their fats up with GM foods, etc.
        We have asked the wrong questions and not the right ones about fats/foods.
        We have incorrectly dichotomized animal foods and plant foods.
        It appears that K2 IS an essential nutrient and we simply have missed this due to myopia/truncated thinking/poor definitions/bad clinical test/stupidity.
        I do not endorse the supplements as much as the lost foods. Eat those.
        One of the biggest issues is how to measure vitamin K status. This is defined as how well all vitamin K-dependent proteins are activated. There is no agreed upon test and the vitamin K researchers do not agree amongst themselves.
        I think CAC=0 is vitamin K repletion.
        Having correction coagulation is only part way to repletion, and this represents the newer findings.

  • JHM

    Hi Joseph. My understanding was a bit different. What I understand is that vitamin K1, which is present in leafy greens and such, is essential to proper blood clotting function, and is in fact so important that the body recycles it to prevent a shortage. K2 on the other hand is what directs the calcium in our body to the bones and teeth, rather than the arteries. The most concentrated vegan food with K2 is natto. There was a study done in Japan that showed women who ate natto regularly had far less incidents of hip fracture. It was attributed to the natto. The non-vegan population used to get K2 from milk and cheese, however, now that commercially raised cows are given feed of soy and corn rather than being pastured, the K2 is no longer there. Sometimes I wonder if the reason the French have lower incidences of heart disease is their consumption of cheese, as well as wine, which has resveratrol. That’s my own thought, but the Japanese study can be found online.

  • Joe

    Came across this site, because I prefer the dry, science based facts, when it comes to food. Thanks for the good work! However, I am a bit disappointed, that most recent findings are not considered or at least mentioned. If there are fancy, serious publications inclining game-changing insights for vegan diets, please at least acknowledge them!

  • Micki Jacobs

    Nope on most of all this. There IS a lot of K1 in veggies, but it is so tightly bound to chloroplasts that very little is absorbed…somewhere in the single digit to about 10%. So citing amounts in a veggie is nice, only you won’t absorb all that. Cooking or juicing seem to make the K1 more available.
    Vitamin K2 in diet, however, is almost completely absorbed.
    There is tons of evidence that vitamin K subclinical insufficiency is very common. But since we have defined vitamin K as vitamin K1 and the role of this family of vitamins as coagulation, we have missed its roles beyond coagulation. And they are HUGE.
    Vitamin K2 is a very interesting topic and one that I suggest you learn a lot more about!
    We make it endogenously in tissues throughout the body (this is new stuff and huge – learn about UBIAD1 and its role in this conversion). The K2 we make this way is the only form of K2 not made by fermentation: MK-4 or menaquinone-4.
    MK-4 is highest in brain and very high in pancreas, kidneys and other tissues.
    This MK-4 binds SXR, and this is also newer info. When it does this, gene expression, the behavior of cancer cells and other effects occur.
    There has been too much emphasis on MK-7, which is high in natto. But natto also has MK-8 and a little K1.
    Our current emphasis on how much of a certain form of K2 is found in a food may miss that the multiple forms of K2 that co-exist may show that it might not be the HIGHEST form amount, but the specific form of K2 that is important.
    The guidelines for vitamin K are completely out of date and do not accommodate the newest data.
    While it is true that K1 is the form of K highest in our current diet (the Western one), we also consume a ton of dihydrophylloquinone (dK) which is made when high K1 oils are hydrogenated. dK fouls up two essential vitamin K actions: it inhibits MK-4 biosynthesis and it inhibits activation of the vitamin K-dependent proteins beyond the coagulation cascade (ones like matrix gla proteins, Gas5, osteocalcin…).
    If you are vegan, you better ferment!
    In the last few decades we have either shunned dietary fats or changed them rather dramatically. In dietary fats we find fat soluble nutrients, which have become the red-headed stepchildren of nutrients: A, D, E and K (well, D is a darling, but D is how the human makes the vitamin K-dependent protein osteocalcin). But K is a very special component of these because you cannot consume too much (unless on warfarin, which will calcify your soft tissues and lead to bad things) since you simply activate those vitamin K-dependent proteins and then you have used the K as much as possible. It does not accumulate to become toxic. It is so essential that there is a way to re-cycle vitamin K for coagulation, but this only helps with this one function of vitamin K and does not address the functions beyond coagulation like bone health, cardiovascular health, cancer cell activity, insulin sensitivity, gene expression and more.
    The cultures with optimal longevity are vitamin K replete.
    Americans are not (mostly, with some exceptions).
    CAC=0 is considered a biomarker that offers the least risk of death or disease and it represents vitamin K repletion, IMO.
    The longer the side chain of a menaquinone (vitamin K2), the more lipophilic and the longer lived in the body.
    those long chain menaquinones are carried by LDL, whereas the shorter chain ones are carried by HDL and K1 is carried by chylomicrons.
    It has been observed that more K2 makes for lower LDL-C and lower TC, which implies that vitamin K status is represented in this misguided biomarker category.
    Look at where we find these: fermented foods, organ meats (esp liver, but also salivary glands, thymus gland, etc), offal, and flat fish or eels (who wallow in bacteria at the bottom of waters).
    We find the shorter-lived MK-4 (remember: not made by fermentation, but found in animal fats and also made by us endogenously) in animal fats, egg yolks.
    Note that we lost all the foods (guts, fermented, animal fats) due to bad dietary guidelines and loss of cultural foods and now we can’t find our butts with both hands.
    Until someone looks at K contents of all foods via liquid chromatography, we will continue to be stupid.
    Until someone assesses the effects of the different forms of K on human health, we will continue to be stupid.
    And until someone understands that our current guidelines are truncated and myopic, we will continue to be stupid.
    BTW, brains REALLY need K2.
    Also, statins and bisphosphonates and NSAIDs inhibit vitamin K2 biosynthesis as well as the dK.
    Thus, Americans are set up to fail due to vitamin K insufficiency and the folks at the vitamin K lab at Tufts still have their heads where the sun don’t shine.
    But you WiLL be hearing about this nutrient/hormone…eventually. It is just tough to find funding when no lucrative drug is the aim.

  • Micki Jacobs

    Read this:
    BMJ openheart
    The health benefits of vitamin K
    They miss so much, but this is a start on admitting that vitamin K plays a role in kidney disease, heart disease, cancer and diabetes.
    Thank goodness we don’t have these as problems…..

  • Frank McIlvenny

    As far as I have studied and read, K1 and K2 provide two totally different vital actions. K1 is a coagulant needed for proper clotting due to injury. That is why after a stent is put in, the patient has to take K1 destroying blood thinners such as warfarin. K2 promotes macrophages ability to remove calcium from arterial walls by consuming them and processing for redistribution for bones and/or teeth where they belong. K2 deficiency can be identified by dental tartar or a heart scan calcium test. Possible causation of K2 deficiency is by naturally occurring flora not being able to produce due to meat, sugar and toxic chemicals in artificial sweeteners. I don’t think it would hurt to take K2 supplements derived from Japanese natto for several months after converting to whole plant based diet until the gut flora can naturally resume production of K2.


    K2 is different from K1 and is not readily available if you have a Vegan diet. I agree with Dr. Mercola that supplementing is essential especially also if you are consumimg oral Vitamin D3. Calcification of arteries due to lack of Vitamin K2 and the little time of efficiency that Vitamin K1 can provide where it lasts from 1-several hours in the Liver is also another factor to look at. K1 simply aids in clotting and not directing the Calcium to the bones and teeth. I admire Dr. Greger and his site for the wonderful work they do, but I do believe on this particular topic Dr. Greger is relying on old studies and not the most recent data…MK7 is the form of K2 that best meet these needs…

    • Dave

      While this idea is oft-repeated on the internet, taking a vitamin D supplement shouldn’t have any effect on whether you take a vitamin K2 supplement unless maybe you are overdosing for some reason. The vitamin D supplement is merely taking the place of vitamin D you would normally get from sunlight exposure. You might as well say “if you take an oral vitamin D supplement or you often go outside during the day, you need to take a vitamin K2 supplement.” And that statement would not be true at all unless you are not getting enough vitamin K2 from other sources.

  • Nbenda

    The question is: can we transform well K1 to K2? Dr Fuhrman advises supplement

  • Nicki

    I’d like to know if Dr. Greger has looked into the vitamin K2 debate any further. I am not a doctor (just a humble nutritionist) but vitamin K1 and K2 have different jobs in our bodies.

  • Justmi

    Will Vit K2 affect normal coagulation, if so how will it do it?
    If I take K2 supplement (90mcg/day), will I end up with PE, DVT?