Vitamin K2 Benefits: The Vitamin You May Not Be Getting Enough Of?

vitamin K2 benefits


You know about vitamin C and vitamin E – but how much do you know about vitamin K2?  You’ll probably be hearing a lot more about this vitamin in the future. Why the interest in vitamin K2?


Research suggests it could be important for bone health and for protecting against heart disease. This vitamin really peaked our interest after reading a few studies so we thought we’d share what we learned with you – how it may be beneficial to your health and what foods you find it in.


Vitamin K2 Benefits: What is Vitamin K2?


Chances are you’ve heard about one form of vitamin K called vitamin K1 that’s important for blood clotting. If you’re deficient in vitamin K1, you’re at risk for easy bruising and abnormal bleeding from the digestive tract. Vitamin K1 is abundant in green, leafy vegetables like spinach, collard greens, Swiss chard, and kale.


If you eat a veggie-rich diet, chances are you’re getting enough vitamin K1 and aren’t at risk for a deficiency unless you have problems absorbing fat-soluble vitamins due to intestinal problems, are chronically malnourished or consume large amounts of alcohol.


Our focus is 0n its counterpart – vitamin K2. Unlike vitamin K1, which is classified as a phylloquinone, vitamin K2 is chemically distinct from vitamin K1 and in a family of compounds called menaquinones. It has a different structure and activity inside your body. Just because you’re eating a veggie-rich diet and getting enough K1 doesn’t mean you’re getting lots of vitamin K2.


That’s because it’s found mostly in fermented foods like aged cheese and a food that’s popular in Japan called natto. Natto is made from fermented soybeans. There’s a reason most people in Western countries don’t eat it. It has a unique and not particularly pleasant texture and smell. There’s a synthetic form of vitamin K called vitamin K3 but it’s used in cancer chemotherapy and isn’t available for human use.


To make natto, soybeans are boiled, soaked and fermented.  What you end up with is a soybean dish with a sticky texture and strong odor that’s unlikely to send you back for more. It’s definitely an acquired taste. Plus, it’s not always easy to find unless you live in Japan. The best place to buy natto, should you want to try it, is a Japanese market.


Other good sources of vitamin K2 include dairy foods from grass-fed animals and organ meats and other fermented foods. Fortunately, bacteria in your intestines make some K2, although probably not enough to offer the health benefits this vitamin seems to have.


Some vitamin K1 is also converted to vitamin K2 but this is probably not enough to offer the full health benefits either.


Unfortunately, it’s not easy to get a lot of vitamin K2 through diet – but why should you want to?

Health Benefits of Vitamin K2


There’s a growing body of research suggesting that vitamin K2 may offer protection against heart disease. K2 appears to play a role in depositing calcium in places where you need it, like your teeth and bones and keeping it away from places you don’t want it like the inside of arteries and blood vessels. 


Atherosclerosis, or hardening of the arteries, is a direct result of calcification of arteries. When calcification involves blood vessels that lead to your heart, it can be a precursor to a heart attack.


How is vitamin K2 protective? It activates a protein called osteocalcin. Osteocalcin not only directs calcium to your bones – it keeps it away from your arteries where it could build-up and lead to heart disease. Osteocalcin is sort of a calcium regulator, making sure this bone-reinforcing mineral goes where it should.


Is there any research to back up vitamin K2 benefits? Yes, there is. A number of studies support the benefits of vitamin K2 for bone health and for the prevention of heart disease. For example, one study showed those with the highest intake of vitamin K2 had the lowest risk for atherosclerotic heart disease.


Another study published in the journal Atherosclerosis showed a lower risk of atherosclerotic heart disease in people who consumed higher levels of vitamin K2 through diet. Vitamin K1 didn’t have the same heart-protective benefits.


Bone Health: Vitamin K2 and Osteoporosis


Another common health concern, especially among women, is osteoporosis. One study found that post-menopausal women who took 45 milligrams a day of vitamin K2 daily experienced improvements in bone density and strength in their hips compared to those taking a placebo.


This is much higher than the amount the typical person gets in their diet. Most supplements have much smaller amounts, measured in micrograms. Based on research, it appears you need about 100 micrograms a day for optimal bone health.


Two large studies called the Framingham Study and the Nurse’s Health Study also showed a reduced risk of fracture in participants who consumed higher levels of vitamin K.


There’s evidence that vitamin K2 improves the architecture of both bone and the collagen that surrounds it while helping to mineralize bone with calcium, making the bone stronger and more resistant to fracture.


How Can You Add More Vitamin K2 to Your Diet?


If you want to get more dietary K2, here are some of the best sources:


  • Natto (by far the best source)
  • Cheese
  • Butter from grass-fed cows
  • Eggs
  • Chicken breast and chicken liver
  • Grass-fed Beef
  • Yogurt
  • Kefir


If you eat a mostly plant-based diet, you’re probably not getting much dietary vitamin K2, although raw sauerkraut is a decent source. It’s always best to get vitamins from dietary sources but it may be tough to get enough vitamin K2 through diet unless you eat the foods on the list above. There are also vitamin K2 supplements available.


Vitamin K2 comes in different forms. Some like MK-4 are short-chained, while the most critical long-chain ones are MK-7, MK-8 and MK-9. It’s the long chain ones that seem to be most important for heart disease prevention, although in animals MK4 is also beneficial.


The best form of protection against heart disease, based on current research, appears to be MK-7, also the form that’s abundant in natto.


Should You Take a Vitamin K2 Supplement?


Keep in mind not all studies show vitamin K2 is strongly protective against atherosclerotic heart disease or osteoporosis. Still, there is some compelling evidence in its favor. Plus, there are really no known adverse effects from taking vitamin K2.


People who are on blood thinners shouldn’t take a vitamin K supplement since it can interfere with the ability of blood thinners to thin blood. It’s also not a good idea to take it if you’re pregnant, diabetic or are prone towards hypoglycemia.


Based on the current studies, we plan on starting a vitamin K2 supplement ourselves in the next few weeks. We thought about buying natto instead but it’s pretty hard to find. Plus, I have to admit we’re a little afraid of the smell and texture. LOL! If you’re more daring, try it and let us know what you think. 🙂



Curr Pharm Des. 2004;10(21):2557-76.
J Nutr. 2004 Nov;134(11):3100-5.
Atherosclerosis. 2009 Apr;203(2):489-93.
Osteoporos Int. 2007 July; 18(7): 963–972.
Arteriosclerosis, Thrombosis, and Vascular Biology. 2011; 31: 2169-2171.

Kristie Leong M.D.

Dr. Kristie Leong and Dr. Apollo Leong are physicians helping you to lead a healthy lifestyle by sharing nutrition and fitness tips and keeping you abreast of the latest health news.