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Let me introduce myself. My name is Mark Sisson. I’m 63 years young. I live and work in Malibu, California. In a past life I was a professional marathoner and triathlete. Now my life goal is to help 100 million people get healthy. I started this blog in 2006 to empower people to take full responsibility for their own health and enjoyment of life by investigating, discussing, and critically rethinking everything we’ve assumed to be true about health and wellness...

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February 23, 2009

Dear Mark: Vitamin K2

By Mark Sisson
137 Comments

Dear Mark,

I’ve been hearing a lot about vitamin K2 lately. Should I be taking vitamin K2 supplements or is a Primal diet sufficient?

Kate

Thank you, Kate, for the question.

You find it in politics, fashion, entertainment, art, even cooking: the “it” figure, new notable, celebrity du jour. As odd as it is, the seemingly humble world of micronutrients isn’t immune from spotlight blitz. Some vitamin or mineral, subject of a timely string of studies, gets thrust into the limelight, and the medical media jumps on the news. Sometimes the hoopla is warranted. Oftentimes, it’s overblown. Most of the time, it’s here today gone tomorrow. Such an odd frame for public health education, I think – and likely the reason many people shut out such reports all together. One day, it’s a miracle nutrient. The next, it’s torn down as “not all that.” Recently, vitamin D has been the one to adorn the marquis. But there’s another novel nutrient chasing its heels: the nebulous, little known vitamin K2.

“K2? Vitamin K. Hmmm. Don’t recall much about that from high school nutrition class. Isn’t it in, like, spinach and stuff?” “Vitamin K. Oh, yes, I think our kids got vitamin K shots right after birth. Was that vitamin K2?” Well, yes to the first, and “close but no cigar for the second.” (That would’ve been vitamin K1.)

So, what’s the deal behind the buzz anyway?

Here’s the story. First, the breakdown. Vitamin K: fat-soluble vitamin – or group of vitamins otherwise known as the naphthoquinones (K1, K2, K3). Call vitamin K1 (phylloquinone) the plant party of the bunch. The spinach association? That would be a source of vitamin K1. Some other K-friendly choices (kale, spinach, Swiss chard, mustard greens, parsley, broccoli, Brussels sprouts, asparagus and avocado) serve up a decent helping. Incidentally, the body can “make” K2 from K1, but it’s not a 1:1 conversion. Though many sources put it at 10:1, the presence of fat (oh, lovely, lovable fat) enhances that conversion process. Finally, vitamin K3 (menadione) is a synthetic version of the vitamin that has limited place in certain medical treatments but is generally considered unsafe and unnecessary for general use.

Vitamin K2 (menaquinone), the nutrient of the hour, has an interesting background. It’s the product of fermentation and usually of intestinal bacteria – either human or animal. Good sources? Meats and dairy products from pasture-raised animals – especially butter and organ meats, aged and curd cheeses, as well as fish eggs. Nonetheless, the much touted mega-source of K2 is natto, a traditional fermented Japanese dish consisting of sticky soy beans that offers a powerful nutritional punch but a rather limited flavor appeal to outsiders.

(As an aside (for those interested), the picture gets more detailed. Within the vitamin K-club, K2 fans out further into various forms (referred to as MK-n), the most talked about of which are MK-7 and MK-4. MK 8-10 forms exist as well. The MK-7 form of vitamin K2, the form that natto champions, lasts a number of days in the body, but MK-4, a shorter span form, comes with the more readily available [and widely eaten] eggs, pasture-raised meats, aged cheeses, etc. Grok is salivating as I type.)

So, what’s the big deal with this nutrient? The full compilation of recent research underscores the idea that K1 and K2 should be appreciated as separate nutrients with distinct physiological actions and benefits. K1, the more familiar vitamin, is known for its key role in directing blood-clotting in the body. (A K1 shot at birth – or series of drops in the first few weeks of life – are common practice in many countries to curtail hemorrhage incidents in newborns.) It also shows anti-inflammatory properties.

The picture for K2 seems to be a bit more varied. K2 appears to be especially key in maintaining bone mineralization and limiting the formation and lifespan of osteoclasts, cells which break down bone. Researchers are increasingly optimistic about K2’s potential for those with or at risk for osteoporosis but are looking to further studies to confirm this association. (Incidentally, K1 alone has not shown the same effectiveness for those with osteoporosis.) In the meantime, other research suggests that K2 may aid cardiovascular health as well by helping prevent or even reverse arterial calcification, a known contributor to cardiovascular disease. But that’s not all. Researchers are also looking at K2 (specifically MK-4) as a therapy for rheumatoid arthritis. And, wait, there’s more! Researchers are also examining the potential of K2 in the prevention of prostate cancer and in the complementary treatment of leukemia and lung cancer.

“But if it’s such a wonder nutrient, why doesn’t it lace a quarter of grocery store products like omega-3s seem to now?” (Oh, there’s a whole other ball of wax.) Besides being a little understood nutrient, the (legitimate) concern has been that many people are on anti-coagulants like Coumadin/warfarin. In fact, they’re generally in need of it, since Coumadin is a vitamin K antagonist. The worry isn’t so much that these people intake vitamin K (especially K2) within their normal diets but that they maintain a consistent dietary measure of it to allow for stable dosing of their anti-coagulant meds. (A complex dance, to be sure.) But I’d suggest that there are other increasingly common medications (digestive related prescriptions and antibiotics) that can limit the absorption of K and alter the body’s ability to naturally convert K1 to K2. Hmmm.

The fact is, for a healthy person not on medications, adequate vitamin K2 is easy to get from the Primal eating plan. Although an RDA for K2 hasn’t been established, Dietary Reference Intakes for vitamin K1 suggest between 90-120 µg/day. (I’ll be on the lookout for updates on K2 doses, but I’ll note that toxicity doesn’t appear to be a problem with vitamin K, and no UL (Tolerable Upper Intake Level) has been established.)

So, how do we get there (and ensure a little extra for good measure)? Undoubtedly, natto has its claim to fame, and kudos to the beans and all who eat them. However, the long-term benefits of (and need for) K2 was undoubtedly relevant to Groks all over the world. A good Primal eating plan (with or without the addition of natto) provides what Grok and we moderns need: grass-fed and rich organ meats, unapologetic egg yolks, ample veggies and greens (with plenty of fresh oils and pasture-raised butter fat, of course!), and – for those who enjoy them – grass-fed cheeses. For specifics, check out a K2 content graph from the Weston Price Foundation.

And that brings us back to the celeb-factor. Sure, we live a very different life from our ancestors: pollution, stress, longer life spans in some cases, etc. Some things we can’t change, but other things we can. A good Primal eating plan that serves up a wide array of nutrients – in the way Grok and his folk ate them (fat, protein, fat) – makes good plain sense. Our current society with its painfully limited and drastically skewed nutritional practices will naturally hit up against deficiencies – both relative and extreme. Add to this the nutritionally depleting cocktails of digestive and antibiotic prescriptions so many people are on these days, and you’ve made several million borderline cases inevitably bad. The result: a good faith but ultimately misguided, “miss the forest through the trees” mentality of “limelight” nutrition. (“K2 to the rescue!”)

Is vitamin K2 an overlooked, underappreciated nutrient that can offer substantial benefits? I believe absolutely yes, and I’ll look forward to reading more studies (and even the popular media reports) in the coming months/years. I love that K2 may serve as an effective and natural supplemental therapy for those with certain medical conditions. Also, for those on digestive or antibiotic prescriptions, the news offers sound advice to see your doctor about getting levels checked and considering supplementation. But what about the rest of us? What are we to garner from the research, the spotlight, the scientific scuttlebutt?  Consider the take home message on K2 as this. Good science has uncovered the fact that K2 is part of good, necessary nutrition. But good nutrition – from a dinner plate or a quality supplement (or both) – isn’t a matter of star performance but of solid ensemble rapport. (And, how could we resist? Yet another reason to go PB.)

Questions, comments, additions, discussion? Let me know your thoughts.

yamada3 Flickr Photo (CC)

Further Reading:

Grok Didn’t Take Supplement So Why Should I?

Scrutinizing Soy

Previous MDA Coverage of K2

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137 Comments on "Dear Mark: Vitamin K2"

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Holly
Holly
7 years 7 months ago

Thank you for the explanation! I now know why the Damage Control Master Formula doesn’t have any vitamin k in it!

JD
JD
7 years 7 months ago

(oh, lovely, lovable fat)

That’s funny!

Conny
Conny
7 years 7 months ago

Thanks for the post today. I learned a lot, as always. I’m always impressed by the detail you provide in each post. At least if I hear the “buzz” about Vitamin K2, I’ll know where I heard it first and be more informed.

Son of Grok
7 years 7 months ago

Wow… that is everything I needed and didn’t need to know about vitamin k. Thank you for all the info Mark!

The SoG

Mosh
Mosh
7 years 7 months ago

The best article on K2 on the internet…I recommend everybody read it:

http://www.westonaprice.org/basicnutrition/vitamin-k2.html

More good reading here:

http://wholehealthsource.blogspot.com/2008/06/vitamin-k2-menatetrenone-mk-4.html

Janet
Janet
1 year 5 months ago

It looks like that article is no longer there–the first one.

Zen Frittata
7 years 7 months ago

Mark,

Like to see your take on B vitamins and the absolute waste of them in drinks these days…since the majority of them just end up going through and never being used if you catch my drift.

Yavor Marichkov
7 years 7 months ago

Didn’t know about that. But I guess that’s why I’m on here, Mark 🙂

Hm, seems vultures get a good portion of K2, no? Eating fermented dead animal and such… Speaking of fermented – the English lords and ladies are said to have a taste for fermented game. And, the french love their stinky cheese.

Now we know WHY.

It’s all about vit K2.

I knew those rich b******s were onto something LOL!

-Yavor

Marc Feel Good Eating
7 years 7 months ago

Mark,

I’m one of the rare westerners that LOVES natto.
I stopped eating it over the past 3 years because of primal/EF life style.
Is it ok to eat you think even though it’s soy?
Eat as a treat every now and than perhaps? Or just a no-no?
Thanks once again for the informative post.

Marc

Valary-Mac
5 years 6 months ago
Soy is one of those few earth-foods that I would not recomend. Us women should stay away from soy, and genetically engineered, or unorganic soy is a big no-no to us all, but I believe guys dont have to worry about it as much. Fermented soy is much different, though, and highly nutritious, but until further studies come through about fermented soy, I would stick mostly to other fermented foods. But natto, unlike tofu or tempeh, is hardly like “soy” at all! It is concidered by trusted natural health gurus to be one of the healthiest foods on the planet.… Read more »
Donna
Donna
7 years 7 months ago

Very Interesting! I’d never thought about vitamin K2,really learned so much from this post.

Great question Kate!

Richard Nikoley
7 years 7 months ago
One of Stephan’s K2 posts at Whole Health Source was linked above, but he has several others as well as peripheral stuff on it. They can all be located here: http://wholehealthsource.blogspot.com/search/label/fat-soluble%20vitamins Because of Stephan’s work here, I read also that Chris Masterjohn piece at the WAPF site, then read most of Nutrition and Physical Degeneration, probably the most important book on nutrition I’ve ever read. Price studied a bunch of non-industrial cultures in the 20’s and 30’s and documented their excellent dental and general health (they didn’t brush, floss, or have dentists, either). I’ve been on K2 (MK-4, the kind… Read more »
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[…] “Vitamin K“ Should we be taking it? Do we get enough in our normal […]

Walter Pittman
Walter Pittman
7 years 7 months ago

Animal foods really aren’t a very good source of K2, except for hard cheeses that have been fermented by bacteria, especially Swiss-type cheeses that have been fermented with by a specific type of bacteria called propionobacteria).

Richard Nikoley
7 years 6 months ago

More K2 news:

Vitamin K2 and Massive Reduction in Heart Disease: Leading Edge

http://www.freetheanimal.com/root/2009/03/vitamin-k2-reduces-heart-disease.html

(And absolutely: MDA is certainly one of those places I mention while on the soapbox). Mark Sisson rocks!

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[…] I knew there was something about natto for K2 that needed paying attention to. K2 from natto is of the mk7 variety, whereas K2 from animal products is of the mk4 variety. I understand that each has a different effect on the body. More here: Vitamin K2 – Should I Supplement with Vitamin K2? | Mark’s Daily Apple […]

Ed
Ed
7 years 6 months ago

Walter Pittman: what about cheddar cheese? This is expensive but good stuff:

http://www.grasslandbeef.com/Categories.bok?category=Grassland+Butter+%26+Cheese%3ARaw+Amish+Cheese

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[…] it promotes the mineralization and growth of bones, working together with calcium, vitamin A, and vitamin K2. Severe deficiency can cause […]

casey
casey
6 years 3 months ago

Great summary about vitamin k2, I appreciate this thoughtful post. However, your comment that humans NEED to eat meat, is false. Humans can be healthy eating meat, but they can also be healthy not eating meat. If there is ever any doubt just go to veganbodybuilding.com and see for yourself.

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[…] Dear Mark: Vitamin K2 […]

Rabbi HIrsch Meisels
Rabbi HIrsch Meisels
5 years 11 months ago

That link to the K graph on the WAPF site is broken.

darren
darren
5 years 11 months ago

I am a coumadine patient and am curious of the effects of K2 on the INR that I work so hard to maintain.

Robert
Robert
5 years 10 months ago

A cardiologist told me last week that K-2 was potassium. Is that so?

Primal Palate
Primal Palate
5 years 4 months ago

THAT made me smile…

I’d love to meet that cardiologist.

Donna
4 years 4 months ago

I asked our pharmacist about K2 and he said it was Potassium. Guess he and the cardiologist make a fine pair. Am going to ask my doctor about K2 as I cannot take osteoporosis medication of any kind.

Karola Behringer
Karola Behringer
4 years 2 months ago

Vitamin K2 is something totally different from Potassium the chemical letter for Potassium is K. Tell your cardiologist to go back to basic chemistry class.

Eric W.
Eric W.
5 years 10 months ago

Robert, that’s hilarious. The symbol for potassium in chemistry is “K”, which I guess is what confused your cardiologist.

Robert
Robert
5 years 10 months ago

Makes sense. Many thanks.

jane
5 years 8 months ago

is k2 safe to take with other medications such as for type 2 diabetes, depression and PILL FOR KIDNEY FUNCTION?

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[…] A – A heated debate over vitamin A and vitamin D (with a bit of K2 sprinkled in) rages on. The Vitamin D Council boys claim A antagonizes and competes with D, while […]

Jared Israel
5 years 8 months ago

The problem is that other than studies conducted at the University Medical Center in Utrecht, The Netherlands, I can find no study (including those you link to) that concludes that K2 prevents arterial calcification. (One study you link to states only that it is a *plausible* hypothesis.) And key people involved in the Utrecht studies are marketing K2 in a very big way (Formed a production company.) Why, after some years, haven’t their claimed findings been duplicated? (Or can someone point to a study where they are actually duplicated?)

Morten
5 years 5 months ago

Go to this website to find studies:
http://www.vitamink2.org/

For patients on anticoagulation therapy, we recommend them to contact their physician for consultation prior to taking vitamin K2. However, based upon NattoPharma documentation, population studies (see e.g. The Rotterdam study) and traditional uses of natto meals, supplementation in the range below 45 µg represents no safety issue for such patients.

So fare no cases has found place where k2 (very important “k2” and not “k1”. in any way damages patients taking anticoagulant medicine. Saw an interview were that was stated by a leading researcher..

Chris Aylmer
Chris Aylmer
3 years 7 months ago

Good point…the Utrecht researchers are involved in the marketing of MenaQ7 too and stand to gain, at least in prestige, if the sales take off. It’s what you call a conflicting interest.

Camilla Bishop (chemistry grad)
Camilla Bishop (chemistry grad)
1 year 10 months ago
Good observation, Jared — but there is a large chunk of information that you are missing called the VKDP, which stands for the vitamin K dependent proteins. They have been researched all over the world. These are enzymes that are activated by vitamin K2; a dozen of them were identified long before the Maastricht (Utrecht?) studies were done. One of the VKDP prevents calcium deposits in the arteries, deposits that make plaque more likely to rupture under stress, such as a blood pressure spike. (We all accumulate plaque as we age.) Another VKDP enables calcium and magnesium to be deposited… Read more »
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[…] Sisson, from whom I take my own dietary cues, is generally against eating beans and legumes, but acknowledges possible health benefits from eating natt? (a fermented soybean paste with is extremely high in vitamin K2).  P?Nu blogger Kurt Harris, […]

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[…] makes pastured milk (and foods derived from pastured milk) better, is that it will have much more vitamin K2 than milk from cows that are mostly grain […]

Brian Sterling
Brian Sterling
5 years 4 months ago

Vitamin K2 has made my teeth whiter and more solid appearing now. I used too many antibiotics at one point in my life and also had GERD, corrected by eating a apple prior to bed and correcting my posture. K2 and Vitamin D rock for correcting the appearance of my teeth.

Brian Sterling
Brian Sterling
5 years 4 months ago

Drink plenty of water too.

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[…] at one study (PDF) indicating high-saturated-fat fermented cheeses containing large amounts of Vitamin K2 actually reduced cardiovascular mortality, but they soon came to their senses and recommended […]

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[…] from A2 casein milk cattle raised by the Masai on fertile grassland, so I bet you’d get some vitamin K2 in there […]

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[…] Vitamin K: Should I Supplement? (Personally, I do take vitamin K. From other reading, I think most of us don’t get enough, even if we are Primal.) […]

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[…] K – See Mark’s post. However, I take some additional K2 to help the vitamin D3 work properly. I am not convinced that […]

Karen
Karen
5 years 1 month ago

I’m 50 yrs old. I seen on TV where Dr. Oz has recommended Vitamin K2 for good bone health. I have OsteoPenne and found that after running for 4 years, my bones are worse. I’m now on Vitamin D (5,000 mg per day) and need to do weight bearing exercises. I’m going to start right away taking Vitamin K2. I’m seeing a specailist at the end of the month for my bones. Thanks for the good advice.

justine
justine
5 years 1 month ago

is vitamin k2 important in absorption of vitamin E?

Jane Longwith
Jane Longwith
5 years 28 days ago

Does vitamin K2 have any affect on the eyes? The reason I ask, the pressure has been up in mine since I started taking it.

C S
C S
2 years 9 months ago

I think K2 may have caused me to develop an atrophic retinal hole. I am myopic and had floaters before, but I only started developing severe floaters and flashes about a week after starting K2. It also gave me high blood pressure and heart palpitations. I was only taking a tiny dose. Too bad, because other than damaging my eyes and maybe my heart, it made me feel great. Scary stuff. I don’t really understand it.

Daryl
Daryl
10 months 19 days ago

Vitamin D works with the K-2. If you’re having symptoms like that, look into your Vitamin D levels. There’s also a book by Jeff T. Bowles on the miraculous health benefits of high doses of Vitamin D. Look it up on Amazon.

Jodie Jantz
Jodie Jantz
5 years 23 days ago

This, I think explains my craving for caviar with all of my pregnancies. Thanks for all of your posts,keep them coming.

Ann Lewis
Ann Lewis
5 years 22 days ago

I appreciated all of the information on vitamin K2. My doctor had never heard of it! But I had heard from a friend about the benefits for osteoporosis. I had been taking Evista and had bad leg cramps from taking it! So, now I’m trying the vitamin for my osteopenia. Should I quit taking my daily low dose aspirin?? I am 66 years old and am on no medications. Thank you!

Peter
Peter
4 years 11 months ago

Mark, what is your opinion on fermented dairy, legumes, and grains. Can they still be part of a primal diet?

Marika Bodnar
Marika Bodnar
4 years 10 months ago

I have severe osteoporosiss; because I work out daily (1hour and a half), the osteo is not visible. Now, I also have lupus. I do not have kidney problems and no hipatitis. Doctors do not say too much about vitamins or herbs. They told me to take calcium with D, but that is all. Would any other vitamin be beneficial for me? I eat the best food; not the most expensive food, but the best. Fresh vegetables, fruits, legums, etc.
Thank you
Marika Bodnar

Chris Aylmer
Chris Aylmer
3 years 7 months ago

Well Marika, if you believe the research, you should buy Vitamin K2 supplement(try vitacost.com)and it is not expensive. It is supposed to be vital in keeping the bones strong, working with vitamin D and calcium as a cofactor.
Do you eat fermented cheeses like camembert, stilton, gouda, mature cheddar and curd cheese? They have lots of natural K2 made by the bacteria in the cheeses. I eat legumes too, but it won’t go down too well on a paleo website!…..and lots of grains, dairy and no meat…and feel in the best of health….better not go on!

John
3 years 7 months ago

Please check out Menacin for Vitamin D, Calcium and Vitamin K2. Naturalarctic.com or visit the facebook group Menacin Natural Vitamin K2 Supplements 😉

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[…] of supplementing with handfuls of calcium pills without considering the roles of vitamins D and K2 in bone mineralization, we still need calcium. We still need that raw building block (and crucial […]

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[…] servings of vitamin K2 rich foods like natto, soft cheeses [try those made from raw milk], or organic liver pate, authentic fermented […]

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[…] other sources site that fish eggs are also quite high in K2. Certain cheeses such as gouda do not need to be made […]

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[…] makes pastured milk (and foods derived from pastured milk) better, is that it will have much more vitamin K2 than milk from cows that are mostly grain […]

Summer
Summer
4 years 6 months ago

Regarding the Weston Price link to the K2 content graph of foods, the link in the article did not work, but here’s a link that does work:

http://www.westonaprice.org/fat-soluble-activators/x-factor-is-vitamin-k2#foods

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[…] – The New Anti-Aging Nutrient April 24th, 2012   dougie_c   No comments Vitamin K2 has been referred to by many as the new vitamin D. While new to most, it is hot, hot, hot and of […]

sprogy
4 years 5 months ago

whaat about K3? will I need another pill?!?

Dr Samir
Dr Samir
4 years 4 months ago

Can we consider Vit K4and Vit K7 have same function and same indication
and as considered menaQ7 and mena K4 are both vit K2

which you prefer
and why
Regards
Dr Samir

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[…] of the better sources of vitamin K2, an oft-ignored nutrient involved in cancer prevention, arterial health, and bone metabolism, is […]

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