Vitamin K2: The Missing Nutrient
Posted By Chris Kresser On May 6, 2008 @ 12:19 pm In Cancer, Food & Nutrition, Heart Disease

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 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, 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 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 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 (soy dish, popular in Japan)

  • Hard cheese

  • Soft cheese

  • Egg yolk

  • Butter

  • Chicken liver

  • Salami

  • Chicken breast

  • Ground 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

 
Comment By Chris
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 [5] 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.
Chris
Comment By Carl
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;
Comment By Chris
Carl, 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.
Comment By Judy
As a strict vegan where would I get the most benefit from K2 vitamin. I don’t consume meat or dairy.
Comment By Chris
Natto or fermented vegetables like sauerkraut. 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.
Comment By roni
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.
Comment By Chris
Hi Roni, here’s a [7] 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 [8] 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.
Best, Chris
Comment By Ben Foster
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.
Thanks,
Ben
Comment By Ben Foster
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?
Ben
Comment By Chris
Ben, 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 [9] 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 [10] 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.
Comment By Alan Reith
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. Alan
Comment By Chris
Alan, see [15] for information about dosage. Unfortunately, we don’t have enough data yet to have specific recommendations. Chris
Comment By Roy Hartsell
I have read and read and nothing about K-2 and stents. Can I take MK-7K-2 with stents in my heart? Why does it say on the warning label not to take if you are on coumadin or other blood thiners? Thank you .Roy.
Comment By admin
The warning reflects a misunderstanding of the function of K2 in the body. Whereas K1 is preferentially used by the liver to activate blood clotting proteins, K2 is preferentially used by the other tissues to place calcium where it belongs, in the bones and teeth, and keep it out of where it does not belong, in the soft tissues ([17]). As to whether it’s safe to take K2 with a stent, I don’t see why it wouldn’t be. In fact, vitamin K2 [18] to reverse arterial calcification in rats. Nevertheless, you should check with your doctor on this question.
Comment By Patti Hill
Thanks Chris. I will look at their website. You say this one of the few supplements you recommend everyone take. Are there others and, if so, what?
On a totally unrelated issue, I have had low WBC counts for the last 10 years, possibly more, and it is low enough that doctors wanted to find a cause but, as yet, have not found one. Do you have any knowledge on this? My internet searches have not helped me and I’m not sure I should even be too concerned about it. One person said that low WBC are not a diagnosis but simply a lab result that might have meaning, so don’t worry about it. Do you have any thoughts?
Patti
Comment By Chris Kresser
It depends on the person. For the average, generally healthy person the fermented cod liver oil / butter oil blend is it. Magnesium is difficult to get with a paleo/primal type diet, which is often what I suggest people follow, and many people are deficient in it so I may suggest that as well. Overall my preference is always to obtain the nutrients we need from food, or at least food-based products like cod liver oil, when possible. Low WBC may indicate a chronic viral or bacterial infection, or it may simply be genetic. If you’ve low WBC your whole life, and you aren’t symptomatic, I wouldn’t worry about it.
Comment By Linda
I’ve just come across your site & this thread on K2. I wonder if you’d share you thoughts on a a bit of a challenge we face at times in my health food store — how to best inform people who are taking blood-thinning drugs about the benefits of K2. We now just suggest that they ask their doctor about how to balance the K2 & the warfarin. We realize of course that virtually no PCP’s are informed on this. I myself take K2 & D3 daily, to help stop my body from taking calcium from my bones & then depositing it in joints, etc. Thanks.
Comment By Chris Kresser
There are [24] demonstrating that rats treated with high doses of warfarin develop arterial calcification, and that K2 protects against this. It can be speculated that humans who take warfarin also develop some degree of calcifications in their arteries, predisposing these patients to heart attacks and strokes. Unfortunately I haven’t seen human studies confirming this. On the other hand, the [25] showed that K2 intake is associated with a significant reduction in CVD. And [26] shows that K2 does prevent arterial calcification. So, although we don’t yet have all of the research we’d like to have on this subject, I think you can piece together a pretty strong argument for taking K2 with warfarin. The caveat is that K2 will probably lower the INR to some degree, so the PCP would need to monitor that. You could also educate them on using EPA & DHA at high doses as an alternative to warfarin. Studies have shown similar CVD-preventative effects, and of course EPA & DHA have benefits warfarin doesn’t have.
Comment By Jane
I am on a Calcium, Vitamin D supplement for thinning bones. It also has 45mcg of vitamin K2. Does this cause blood clots, since that what I understand vit K does?
Comment By Chris Kresser
Vitamin K2 and vitamin K have different effects. K2 primarily regulates calcium metabolism (i.e. makes sure calcium goes into the bones and teeth where it belongs and not the soft tissue), whereas vitamin K has a stronger effect on coagulation.
Comment By Ann
Chris, thanks for your information on K2. I am researaching benefits of K2 for my situation. I did not have osteoporosis until I had been on Advair for a few years for COPD from chronic bronchitis. I have been on Actonel for 1 yr and 7 months. Just had a bone density test that showed I have declined again, 12%. Now at -3.3. I have taken calcium supplements for most of my adult life and have been taking D3 and magnesium for several years. I have a history of DVT, so I take Persantine, which is not a blood thinner, but keeps my platelets from sticking together. I transitioned to vegan and have been free of animal products for one year. I do not eat the high fat raw, but try to eat mostly fruit, veggies, legumes, and small amount of whole grains and try to keep fats low (nuts and EVO). I am wondering if 1) K2 is right for me, 2) if my diet contributed to the bad report, 3) would K2 help if I still have to take Advair (steroids). Would Kefir have K2? What about rejuvalac?
Comment By Chris Kresser
Ann: I don’t advocate a vegan diet for multiple reasons, and this is one of them. It’s impossible to get the nutrients (from food) necessary for optimal health with a vegan diet. I’ve written about that elsewhere on the blog. My recommendation for dealing with your problem would include a diet rich in grass-fed animal products, fermented cod liver oil (supplying A, D, K2, E and other quinones in their natural, whole-food form), and regular consumption of whole, fatty fish like salmon. K2 is certainly right for you, as is a whole-food form of D and A. Kefir probably does have some K2, since it’s fermented – especially if made with milk from grass-fed cows. Sauerkraut is another potential source.
Comment By Ann
Chris, thank you for you reply. This info has helped. I will make diet changes. I know that I am not getting enough calories with vegan diet, but in going low-fat vegan, I was trying to lower cholesterol which has been high for years; plus, acidic animal foods supposedly make osteooporosis worse. I am allergic to seafood, so can’t do fish or cod liver oil. I do have Ann Wigmore’s books with instructions on how to make sauerkraut. It is not easy to find the right way to eat to obain better health. This blog has offered more information that just reading an article would not provide. Thanks again!
Comment By CJ
I’m 37 and I recently had a brief bout with heart palpitations (they’ve since gone away), and an Echocardiogram showed a small amount of mitral calcification. Since the palpitations had gone away and I had no other symptoms, the cardiologist said no other action or follow up was necessary. I did some reading and began supplementing my diet with 150 mcgs of MK-7 K2 from Jarrow.
Any hope that the K2 may help “de-calcify” my mitral valve and leaflets?
Comment By Chris Kresser
K2 has been shown to reverse arterial calcification in some people. So yes, it has that potential.
Comment By anonymous
Dear Chris nice site. I was recently diagnosed with mild MS, I had very low levels of vit D but have been supplementing with d3 both with solgars cod liver oil and Thornes d3 powder supplement, i am concerned after reading weston price that my A to D levels are out of wack and as I have mild osteopaenia I am also worried about how to safely calcium supplement as Im aware that magnesium becomes a real issue for me with noise sensitivity and jumpiness. I do take a multi by Thorne which I rotate with a B group. Im thinking of starting fermented cod and butter oil, but would love to get some personal feedback and reviews [beside weston price] as to its effectiveness. Also with multis and the research into beta carotene, vit e etc, wasnt it a case of artificial beta carotene and only testing D-Alpha tocepherol rather than the multitude of tocepherols that occur in nature?
Comment By Chris Kresser
Hi anonymous,
Overall I think vitamin D, magnesium & K2, as well as regulating cortisol and blood sugar levels, are more important for maintaining bone health than calcium supplementation – which can be dangerous in the absence of those other factors. FCLO/butter oil blend is the best product I’m aware of for fat-soluble vitamin needs. It’s extremely effective, and a very high quality product. I use it with nearly all of my patients, and I take it myself.
Yes, the research shows that synthetic vitamins and antioxidants are either not beneficial, or even harmful. That’s why it’s so important to get our nutrients from real food.
Pingback By Is Butter Healthy? Part 3: Vitamin K2 Benefits | SicklyCat.com
[...] Vitamin K1 comes from plant sources (like spinach), while vitamin K2 comes from animal sources (like grass fed butter and liver). Conventional health information doesn’t make much of a distinction between vitamin K1 and vitamin K2, but their functions in the body are quite different. Vitamin K1 plays the role most of us associate with vitamin K: supporting healthy blood clotting mechanisms. Vitamin K2, however, is in another league entirely. Its role in bone health, dental health and heart health appears to be completely separate from vitamin K1: “A 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.” From The Healthy Skeptic blog [...]
Comment By Isobelle Phillips
Hi Chris, I am taking asprin because I have had a blood clot in my leg which travelled to my lung. I have rhumatoid arthritis which I am controlling myself without drugs by living on mostly raw foods with plenty of vegetable juices. I have had a bone scan and it has shown that I have bone thinning.I do take a calcium supplement in the form of Lifestream natural calcium. I want to take vitamin K2 in the form of natto capsules. Would it be safe to stop the asprin. If so would I wait a day or so before starting to take the K2.Thanks
Comment By Herm Brownstein
Dear Chris, I recently came across your site while googling info re K 2 in low fat Edam vs ordinary Edam. My interest in K2 stems from my recent diagnosis by my new cardiologist – that my aortic valve is only opening 0.7cm vs 3cm fully. That started me on research to look for a way to stop or reverse the process. That led me to Dr James Howenstine’s article, “Vitamin K2 Controls Removal OF Calcium from Arteries……….” published in NewsWithViews.com. I’m greatly impressed by both of you – in part – because you both reference many of the same studies. Dr Howenstine tells of the dangers of coumadin, which I have been on for almost 10 years because of chronic AF. He also states it is easy to withdraw from coumadin and cites a number of supplements and dosages as substitutes. I’m now in the process of weening myself off coumadin. If you can recommend any specific supplements, I’d appreciate your recommendations. I’d like to add a few comments to your blog (feel free to edit any of the above): nattokinase is one of the best sources of K2 and most nattokinase on the market is devoid of it; one of your questioners complained of bone spurs and asks if D3 would help. Your answer refers to K2. I don’t believe D3 contains K2. Many thanks for a very informative column. browny
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[...] the USDA recommends a diet high in calcium but woefully LOW in co-factors like vitamin K2 that cause us to retain the calcium we consume. Ever wonder why Americans take in so much calcium [...]
Pingback By B-r-o-t-h | CaveGirlEats
[...] I believe that there is a tendency within the “Paleo” community to simply delete typical “neolithic” foods from the diet (bread, processed junk, soybean oil) while still sticking to the foods that lie within our individual paradigms. More meats – still mostly muscle meats; more veggies – maybe a few new ones; and more fats – probably more of what we already liked. We totally delete all modern dairy (with good reason). But the traditional cultures studied by Weston A. Price used organ meats, marrow, bone broths, raw dairy, and sometimes even animal blood (ick) to stay unbelievably hearty and robust. From my self-experimentation, I believe that even a good Paleo-style diet can be deficient in many of the nutrients provided by these foods. How many of us eat liver? Fermented and cultured foods? How many of us are getting sufficient pre-formed Vitamin A or Vitamin K2? [...]
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[...] Vitamin K: The Missing Nutrient Recent research has demonstrated the essential role of vitamin K2 in promoting optimal health. Unfortunately, K2 has been badly misunderstood for many years. [40] .. [...]