Vitamin K2: The Missing Nutrient

cheeseA study recently published by the European Prospective Investigation into Cancer and Nutrition (EPIC) has revealed that increased intake of vitamin K2 may reduce the risk of prostate cancer by 35 percent. The authors point out that the benefits of K2 were most pronounced for advanced prostate cancer, and, importantly, that vitamin K1 did not offer any prostate benefits.

The findings were based on data from more than 11,000 men taking part in the EPIC Heidelberg cohort. It adds to a small but fast-growing body of science supporting the potential health benefits of vitamin K2 for bone, cardiovascular, skin, brain, and now prostate health.

Unfortunately, many people are not aware of the health benefits of vitamin K2. The K vitamins have been underrated and misunderstood up until very recently in both the scientific community and the general public.

It has been commonly believed that the benefits of vitamin K are limited to its role in blood clotting. Another popular misconception is that vitamins K1 and K2 are simply different forms of the same vitamin – with the same physiological functions.

New evidence, however, has confirmed that vitamin K2’s role in the body extends far beyond blood clotting to include protecting us from heart disease, ensuring healthy skin, forming strong bones, promoting brain function, supporting growth and development and helping to prevent cancer – to name a few. In fact, vitamin K2 has so many functions not associated with vitamin K1 that many researchers insist that K1 and K2 are best seen as two different vitamins entirely.

A large epidemiological study from the Netherlands illustrates this point well. The researchers collected data on the vitamin K intakes of the subjects between 1990 and 1993 and measured the extent of heart disease in each subject, who had died from it and how this related to vitamin K2 intake and arterial calcification. They found that calcification of the arteries was the best predictor of heart disease. Those in the highest third of vitamin K2 intakes were 52 percent less likely to develop severe calcification of the arteries, 41 percent less likely to develop heart disease, and 57 percent less likely to die from it. (Geleijnse et al., 2004, pp. 3100-3105) However, intake of vitamin K1 had no effect on cardiovascular disease outcomes.

While K1 is preferentially used by the liver to activate blood clotting proteins, K2 is preferentially used by other tissues to deposit calcium in appropriate locations, such as in the bones and teeth, and prevent it from depositing in locations where it does not belong, such as the soft tissues.(Spronk et al., 2003, pp. 531-537) In an acknowledgment of the different roles played by vitamins K1 and K2, the United States Department of Agriculture (USDA) finally determined the vitamin K2 contents of foods in the U.S. diet for the first time in 2006. (Elder, Haytowitz, Howe, Peterson, & Booth, 2006, pp. 436-467)

Another common misconception is that human beings do not need vitamin K2 in their diet, since they have the capacity to convert vitamin K1 to vitamin K2. The amount of vitamin K1 in typical diets is ten times greater than that of vitamin K2, and researchers and physicians have largely dismissed the contribution of K2 to nutritional status as insignificant.

However, although animals can convert vitamin K1 to vitamin K2, a significant amount of evidence suggests that humans require preformed K2 in the diet to obtain and maintain optimal health. The strongest indication that humans require preformed vitamin K2 in the diet is that epidemiological and intervention studies both show its superiority over K1. Intake of K2 is inversely associated with heart disease in humans while intake of K1 is not (Geleijnse et al., 2004, pp. 3100-3105), and vitamin K2 is at least three times more effective than vitamin K1 at activating proteins related to skeletal metabolism. (Schurgers et al., 2007) And remember that in the study on vitamin K2’s role in treating prostate cancer, which I mentioned at the beginning of this article, vitamin K1 had no effect.

All of this evidence points to the possibility that vitamin K2 may be an essential nutrient in the human diet. So where does one find vitamin K2 in foods? The following is a list of the foods highest in vitamin K2, as measured by the USDA:

Foods high in vitamin K2

  • Natto
  • Hard cheese
  • Soft cheese
  • Egg yolk
  • Butter
  • Chicken liver
  • Salami
  • Chicken breast
  • Grond beef

Unfortunately, precise values for some foods that are likely to be high in K2 (such as organ meats) are not available at this time. The pancreas and salivary glands would be richest; reproductive organs, brains, cartilage and possibly kidneys would also be very rich; finally, bone would be richer than muscle meat. Fish eggs are also likely to be rich in K2.

It was once erroneously believed that intestinal bacteria are a major contributor to vitamin K status. However, the majority of evidence contradicts this view. Most of the vitamin K2 produced in the intestine are embedded within bacterial membranes and not available for absorption. Thus, intestinal production of K2 likely makes only a small contribution to vitamin K status. (Unden & Bongaerts, 1997, pp. 217-234)

On the other hand, fermented foods, however, such as sauerkraut, cheese and natto (a soy dish popular in Japan), contain substantial amounts of vitamin K2. Natto contains the highest concentration of K2 of any food measured; nearly all of it is present as MK-7, which research has shown to be a highly effective form. A recent study demonstrated that MK-7 increased the percentage of osteocalcin in humans three times more powerfully than did vitamin K1. (Schurgers & Vermeer, 2000, pp. 298-307)

It is important to note that commercial butter is not a significantly high source of vitamin K2. Dr. Weston A. Price, who was the first to elucidate the role of vitamin K2 in human health (though he called it “Activator X” at the time) analyzed over 20,000 samples of butter sent to him from various parts of the world. As mentioned previously in this paper, he found that the Activator X concentration varied 50-fold. Animals grazing on vitamin K-rich cereal grasses, especially wheat grass, and alfalfa in a lush green state of growth produced fat with the highest amounts of Activator X, but the soil in which the pasture was grown also influenced the quality of the butter. It was only the vitamin-rich butter grown in three feet or more of healthy top soil that had such dramatic curing properties when combined with cod liver oil in Dr. Price’s experiments and clinical practice.

Therefore, vitamin K2 levels will not be high in butter from grain-fed cows raised in confinement feedlots. Since the overwhelming majority of butter sold in the U.S. comes from such feedlots, butter is not a significant source of K2 in the diet for most people. This is yet another argument for obtaining raw butter from cows raised on green pasture.

New research which expands our understanding of the many important roles of vitamin K2 is being published at a rapid pace. Yet it is already clear that vitamin K2 is an important nutrient for human health – and one of the most poorly understood by medical authorities and the general public.

Recommended links

  • On the Trail of the Elusive X-Factor
  • The Vitamin You Need to Prevent Prostate Cancer
  • K2 Associated with Reduced Risk of Coronary Heart Disease

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  1. Bryan - oz4caster’s avatar

    Excellent article! I’d be interested to find out if kefir has more K2 than the milk it is made from. I would not be surprised if it did.

    I added the little bit of K2 data for food that I could find to my Excel dietary nutrition calculator. Most of what I found came from Chris Masterjohn’s WAPF article on K2 in Wise Traditions.

  2. Chris’s avatar


    Thanks for your comment.

    Kefir definitely has more K2 than milk, as K2 is a product of bacterial fermentation. Natto, a fermented soy product, is the highest natural source of K2.


  3. Jeanie’s avatar

    Hi, Does any one no where I can buy vitk2 Natto that is non gmo and certified organic? I just read an article stating that many of the soy beans grown in the US that have been sold to Japan have tested positive for gmo even though they were organic. I would like to buy the food instead of the suppliment in hopes that it is cheeper but also pure. 

  4. Peggy’s avatar

    I have found an organic natto at our local Japanese market, Nijiya Market, a chain in CA. They also feature several non-GMO versions. You could also make your own (Gold Mine carries the starter, as does Nijiya Market). The food is the best way to go if you can eat it. Then you also get nattokinase benefits (helps dissolve clots) as well as the K2. About 1/4 of a 100gm pkg eaten every other day should protect you well enough due to the MK-7 long lasting form of K2. BTW, natto can be frozen and re-frozen without significant loss several times.

  5. Carol Hitchcock’s avatar

    So grateful for the info on K-2.  I’m just discovering this and have just discovered at the age of 67 from a cat scan that I have minimal calcification and minimal calcium deposits in my main aeorta in the stomach area.  It is so satisfying to have an answer and unfortunately most doctors don’t seem to offer this as they are more of a reporter and less of a problem solver or researcher.                                                  Thanks so much!                                 Carol 

  6. Chris’s avatar


    I’m glad you’ve found this information to be useful, and welcome to the blog!


  7. Jean’s avatar

    Hi, I have bone spurs on my heals. It would be great if vk2 worked to heal them. I quit my job as a PE teacher becuase of the pain. I am just hoping to find some that isn’t made from gentically modified soy beans.

  8. Chris’s avatar


    Whenever possible, I prefer to get necessary nutrients from food sources. In the case of K2, you can eat fermented foods like sauerkraut, kim chi, kefir, yogurt and natto. Hard cheeses, grass-fed butter, egg yolks and chicken liver are also good sources.


  9. rose tubbs’s avatar

    I have been on HBP medication which includes calcium chanel blockers (admittedly a small dose) for nearly 3 years -monitoring shows blood pressure now well controlled but I hate taking pharmaceutical drugs. Dr is very loathe to give me info on this drug and I have always wondered what would be the natural alternative. With your info it seems to become a bit clearer and I would lke to take a little K2 or at least eat sauerkraut and more cheese & egg yolk. What do you think?

  10. Chris’s avatar


    I’m not aware that K2 has any specific effect on blood pressure.  While I can’t provide any medical advice, as I’m not a doctor, I can tell you that there are several ways to lower blood pressure naturally, including stress reduction, meditation, acupuncture, and dietary therapy.  Meditation is particularly effective, and is completely non-invasive – not to mention free!

  11. carl’s avatar

    does soy yogurt have k2 as it is a fermented soy product?

  12. Chris’s avatar

    Hi Carl,

    My guess is that soy yogurt doesn’t have much K2. Commercial yogurt is not fermented for very long, so the amount of K2 produced in the process is likely to be fairly low. Regardless, I wouldn’t recommend soy yogurt for other reasons. Soymilk, which soy yogurt is made from, is highly processed and poses many risks to health. As little as one cup of soy milk per day was recently shown to significantly reduce sperm counts in men, and it can cause similar hormonal problems in women. Please see my recent articles on soy for more information.

    If you’re eating soy yogurt because you’re sensitive to dairy products, try making yogurt at home from scratch. If you ferment it for 24 hours or longer, all of the lactose will be consumed by the probiotic organisms. Many people who are lactose-intolerant are able to eat yogurt when it’s made this way. Plus, the longer fermentation time means that the K2 content will be much higher – especially if the yogurt is made from whole milk that comes from grass-fed cows. Rapidly growing green grass (in Spring and Fall) is very rich in K1, which cows convert to K2. That’s why grass-fed butter and milk/cheese are high sources of K2.


  13. carl’s avatar

    That is hard to believe as they eat a lot of soy in China and it doesn’t look like they have problems with feritlity as it is the world’s most populus country; my soy yogurt is organic soy;

  14. Chris’s avatar


    It is a common misconception that Asians eat “a lot of soy”.  In fact, that’s not true.  Soy has traditionally been used as a condiment in Asia, and even then it was carefully prepared (through long fermentation) to destroy the phytates found in soy that inhibit nutrient absorption.

    Many vegetarians in the USA, and Europe and Australia would think nothing of consuming 8 ounces (about 220 grams) of tofu and a couple of glasses of soy milk per day, two or three times a week. But this is well in excess of what Asians typically consume; they generally use small portions of soy to complement their meal. It should also be noted that soy is not the main source of dietary protein and that a regime of calcium-set tofu and soymilk bears little resemblance to the soy consumed traditionally in Asia.

    Perhaps the best survey of what types/quantities of soy eaten in Asia comes from data from a validated, semi quantitative food frequency questionnaire that surveyed 1242 men and 3596 women who participated in an annual health check-up program in Takayama City, Japan.  This survey identified that the soy products consumed were tofu (plain, fried, deep-fried, or dried), miso, fermented soybeans, soymilk, and boiled soybeans. The estimated amount of soy protein consumed from these sources was 8.00 ± 4.95 g/day for men and 6.88 ± 4.06 g/day for women (Nagata C, Takatsuka N, Kurisu Y, Shimizu H; J Nutr 1998, 128:209-13). 

    According to KC Chang, editor of Food in Chinese Culture, the total caloric intake due to soy in the Chinese diet in the 1930’s was only 1.5%, compared with 65% for pork.

    Compare that to the 220g that the average American consumes in a single 8 oz. glass of soymilk.  What’s more, almost all processed food these days has some form of soy in it, whether in the form of soybean oil, soy protein, soy flour or soy lecithin.  The reality is that most Americans – especially those who are “health conscious” – are consuming far more soy than Asians ever have, and far more than it is healthy to eat.

    Did you read any of the information I linked to?  I’d really recommend you do that before making up your mind one way or the other.  Here’s a direct link to the study which demonstrated a significant decrease in sperm count in males consuming as little as one cup of soy milk per day.  It was published in a major, peer-reviewed journal by a reputable researcher working at the Harvard School of Public Health. 

    I’ve written about other dangers of soy consumption on this blog (I provided the link in my previous post).  There is overwhelming evidence that soy is harmful too our health in the quantities we’re consuming it in.  This is true whether the soy is organic or not. 


  15. Pingback from Best of Expo West: Tasty Freeze-Dried Natto, Rich in Vitamin K2 | CHEESESLAVE on March 9, 2009 at 4:56 pm

  16. Judy’s avatar

    As a strict vegan where would I get the most benefit from K2 vitamin.  I don’t consume meat or dairy.

  17. Chris’s avatar

    Natto or fermented vegetables like sauerkraut.

  18. Judy’s avatar

    Does this have to be made or can it be purchased somewhere like whole foods markets, etc.  How do you prepare it?

  19. Chris’s avatar

    Both natto and sauerkraut can be purchased at health food stores.  It’s important to get organic natto made from non-GMO soy.  See the posts earlier in this thread for more info.

  20. roni’s avatar

    hi chris,  thank you for this information! until recently i was unaware of the research findings on k2.  i wonder if you have any idea what a good amount of k2 per day is, and what is the designation for it? units? micro or miligram?  and lastly, any idea of the amount of k2 in trader joe’s organic low fat yogurt?  does the lower fat content lower the k2 level?
    thanx for your reply.

  21. roni’s avatar

    hi again chris, i have another question for you. what do you think of bragg’s liquid amino’s?    thanx.

  22. Chris’s avatar

    Hi Roni,

    Here’s a list of the vitamin K content of various foods, measured in micrograms. I recommend reading that entire article, actually.

    I don’t recommend any low-fat products, including low-fat yogurt. See here for an explanation. The fat is where all of the fat-soluble vitamins will be found, including K2. Therefore low-fat yogurt will have less K2 (and other beneficial nutrients) than whole-fat yogurt.

    I don’t recommend a specific target for K2. I suggest that people eat plenty of fermented foods (sauerkraut, kefir & yogurt made from grass-fed milk), grass-fed butter, hard cheeses, and egg yolks (from pasture-raised chickens). If you do that, you’ll get all the K2 you need.


  23. Chris’s avatar

    I don’t recommend Bragg’s for two reasons:

    1) Like most products with “spices” or “natural flavors” listed as ingredients, Bragg’s contains MSG. The industry avoids listing MSG on the label by putting MSG in spice mixes, and if the mix is less than 50% MSG, manufacturers don’t have to put it on the label.

    2) Too much processed soy can cause numerous health problems.


  24. Ben Foster’s avatar

    Dear Chris,
    I’ve only recently come across the K2 studies. They raise a series of questions for me. My major concern is prostate cancer, and I am intrigued by the studies showing a reduced danger of advanced prostate cancer for men who consume more K2. But the sources for K2 are primarily animal, especially dairy. This finding directly disagrees with many other recent finding that correlate high dairy intake with high risk for prostate cancer. The Japanese, who eat little dairy, have one quarter the prostate cancer that we Americans suffer. In countries with high dairy intake, prostate cancer rates are also high. Colin Campbell in The China Study asserts that diary interferes with the body’s use of vitamin D, and that high dairy intake causes an enormous increase in aggressive and advanced prostate cancer. Campbell recommends a vegan diet–no animal based food at all. He claims that population studies demonstrate that vegan populations do not suffer from the  high incidence of cardiovascular disease and cancer that we in the West do with our diets heavy on animal protein. Campbell asserts that it is the protein especially in dairy that makes it so harmful to Western diets. In the recent study of K2, cheeses, especially Gouda and Edam, were recommended as sources of K2. Since this contradicts so directly the findings of Campbell, I am puzzled. But also hopeful. Because of my prostate cancer fears, I have given up nearly all dairy, and the part I miss most is cheese. How I would love to find out that at least some cheeses come in with  a clean bill of health in regards to the prostate. My other questions are these: does miso qualify as a source of K2? What about supplementation with nattokinase? Nattokinase supplements are easy to come by, but natto is scarce in these parts, and I’m not eager to make my own. Sorry to throw so many questions at you. Credit it to your raising important issues.

  25. Ben Foster’s avatar

    Chris: Re:K2 studies showing reduced prostate cancer risk. But the studies point to dairy sources of K2, e.g.cheeses. Dairy is implicated in prostate cancer. So: Is it good or bad for prostate health to eat cheeses? And what of nattokinase supplements instead of natto? Does miso fit into the K2 picture?

  26. Chris’s avatar


    I haven’t had a chance to review the studies you mention linking dairy consumption to prostate cancer risk, but I am skeptical. Were they observational studies? Were they well-designed? Did they control for other dietary factors? What type of dairy products were they? If the studies were anything like the recent study which “proved” that eating red meat is bad for you (see my article Where’s the Beef for more on that ridiculous claim).

    Along those same lines, before you put too much stock in Campbell’s China Study, I’d highly recommend reading this review of his book. Make sure to read Campbell’s response to the review, and Masterjohn’s response to Campbell. Many of the claims made by Campbell aren’t even supported by his own data. That’s unfortunately all-too-common when study authors have a strong agenda, as Campbell did.

    Also keep in mind that pasteurized dairy and raw dairy, which is what I advocate eating whenever possible, aren’t the same foods. Raw dairy still contains all of the enzymes and probiotics naturally present in the milk. You could say it’s a “whole food”. The pasteurization process (high heat) kills those enzymes and probiotics, which makes pasteurized dairy more like a processed food. Many people don’t have lactase in sufficient amounts to digest the lactose in milk; that’s why people like me thrive on raw milk but cannot tolerate much pasteurized milk at all.

    K2 must always be consumed with adequate amounts of D and A. That’s just one of many reasons why a vegan diet is a bad idea.

  27. Pingback from CHEESESLAVE | BBQ Natto with Shrimp on June 17, 2009 at 10:59 am

  28. KimC.’s avatar

    Oh, I hate to be a bother when you’re busy trying to complete your studies, but this is of great interest to me as my husband suffers from DISH – Diffuse Idiopathic Skeletal Hyperostosis – essentialy calcification of the anterior ligaments of the spine. Although quite rare in a man of his age (he’s only in his late 40’s), his Rheumatologist has told him that dietary changes would not make a difference, but I wonder if K2 supplementation could be of assistance here.

    I’ve been unable to find the original Spronk research article quoted in your post and any assistance in locating it, if at all possible, would be greatly appreciated.

    Thanks so much for your terrific blog.
    Kim C.

  29. Chris’s avatar

    Hi Kim,

    I’m sorry to hear about your husband’s condition. I’m not familiar with it specifically, so it’s difficult to say whether K2 supplementation would help. However, as K2 regulates calcium metabolism in the body (putting it where it should be, and not where it shouldn’t be), I imagine it may be helpful. Unfortunately I don’t have the original Spronk article any longer. Here is a search for “spronk k2″ on Google Scholar. You might want to check through the results. Also, if you haven’t already read it, I highly recommend checking out Chris Masterjohn’s article on K2 on the WAPF website. Good luck!

  30. KimC.’s avatar

    Wow, thanks so much for your prompt and helpful reply, Chris. I had no idea that “google scholar” existed. And yes, it was that sentence that caught my attention: K2 is preferentially used by other tissues to deposit calcium in appropriate locations, such as in the bones and teeth, and prevent it from depositing in locations where it does not belong, such as the soft tissues.(Spronk et al., 2003, pp. 531-537
    Thanks again and best wishes to you in your academic endeavors.

  31. Sam’s avatar

    I tried to warn people at work about danger of eating soy products, they did not belive me. After I emailed this link, many had a second thought, especially pregnant women.
    About cheese. After reading a book
    A Cancer Battle Plan by David J. Fraham
    I stopped eating cheese in any form.

  32. Mona’s avatar

    My mother has been k2 for 3 months. She has recently noticed black patches on her face and arms, swelling on one side of face and inside mouth, pain behind her ear leading to her neck. Could this be a side effect of K2? She is on statins, and aspirin.

  33. Chris’s avatar

    Hi Mona,

    I’ve never heard of K2 causing any side effects like the ones you mention. I think it’s far more likely that the statins are causing those problems, but it’s impossible to say for sure. Have you read my articles on statins? They are not proven to be beneficial for women of any age. Perhaps your mom should consider discontinuing them.


  34. Ed’s avatar

    I think marrow also has lots of K2, so a good marrow bone broth ought to be a good diet addition. I’m still looking for a good reference, though, to support that.

  35. Alan Reith’s avatar

    What is the recommended minimum intake of Vitamin K2 per day for and adult male (me) with calcium in the arteries? Doctor has put me on Caduet (a statin I believe) which is giving me several unwanted side effects.
    I have sourced Natto (Nippon Food Supplies) and am planning to replace the Caduet with it.
    Any comments would be greatly appreciated.

  36. Chris’s avatar


    See this article for information about dosage. Unfortunately, we don’t have enough data yet to have specific recommendations.


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