Vitamin K2 Benefits Revisited: Why Take Vitamin K2?

vitamin k2 benefits


Vitamin K2 benefits again? Yes, we’ve talked about vitamin K2 in a previous post but since then we’ve received lots of emails about this lesser-known form of vitamin K that’s getting more airplay these days.


Specifically, people have been asking about vitamin K2 supplement dosage information for supplements. So, we decided to dig a little deeper into vitamin K2 – why it’s important, how to get enough of it and how to choose a vitamin K2 supplement.


Feel free to email with questions if there’s something that’s not clear.


Vitamin K2 Benefits


There are two natural forms of vitamin K – vitamin K1 and vitamin K2. You need vitamin K1 for your blood to clot normally. Most people aren’t deficient in vitamin K1 since bacteria inside your intestines make it. Plus, it’s abundant in green, leafy vegetables. If you take antibiotics, you could become deficient in vitamin K1 because you destroy some of the intestinal bacteria that make, but, vitamin K1 deficiency is not a common problem.


What you likely get less of through diet is vitamin K2. Vitamin K2 has benefits that go beyond helping your blood clot. Studies show it helps to prevent “abnormal calcification.” Wondering what that means?


Vitamin K2 helps direct the calcium you get through diet to the places it should be – in your teeth and bones – and keep it away from areas that it shouldn’t be – like inside arterial walls where it can lead to atherosclerosis. Some studies have linked higher intakes of vitamin K2 with a lower risk for coronary artery disease.

Bone Health and Vitamin K2


There’s also evidence that vitamin K2 plays an important role in bone health. Although vitamin K1 appears to play some role in maintaining bone density, vitamin K2 appears to be a more powerful force for protecting your bones. The Framingham Study and the Nurse’s Health Study both showed a reduced risk of bone fractures among women who had higher vitamin K2 levels.


In another study, vitamin K2 combined with calcium proved more effective than calcium alone for maintaining bone density. Participants in this study also experienced fewer bone fractures. The dose in this study was 45 milligrams of K2 and 150 milligrams of calcium daily.


Another study showed vitamin K2 combined with vitamin D3 was more effective for maintaining bone density than either used alone. The best way to protect yourself against bone loss is to get adequate amounts of vitamin D, vitamin K2, and calcium. They work together to keep your bones healthy.


There’s other preliminary research suggesting vitamin K2 may reduce the risk for certain types of cancer, including prostate cancer. It’s really too early to say whether you can add cancer prevention to the list of benefits vitamin K2 offers. All in all, vitamin K2’s strength seems to be regulating calcium – keeping it in your bones and out of the walls of your arteries. That’s a pretty tough job in and of itself, don’t you think?


Why You’re Probably Not Getting Enough Vitamin K2


You can easily meet your vitamin K1 requirements eating green, leafy vegetables and avoiding antibiotics. It’s not so easy with vitamin K2. A small amount of vitamin K1 is converted to K2 by intestinal bacteria but, from what we’ve read, the amount is pretty small.


It’s also a challenge to get vitamin K exclusively through diet. Foods highest in vitamin K2 are natto (a Japanese fermented soy product), egg yolks, chicken liver and dairy products from grass-fed animals. If you eat a vegan diet, you probably don’t have very high vitamin K2 levels.


Why Take Vitamin K2?


A number of readers asked about taking a vitamin K2 supplement. As long as you’re not taking a blood thinner or on dialysis, getting vitamin K2 in supplement form is likely safe. You shouldn’t take a vitamin K2 supplement if you’re pregnant or breastfeeding either. If you take a supplement, take it with a fatty meal since it needs fat for proper absorption.


Vitamin K2 Dosage and Types


When you read a vitamin K2 label, you may see MK-4 or MK-7 listed. MK-7 is produced by fermentation of natto, the Japanese soy food we mentioned as being rich in vitamin K2. MK-4 comes from animal sources. In some cases, MK-4 is produced synthetically.


We prefer the MK-7 form for a few reasons. MK-4 has a short half-life, meaning it doesn’t stay in your system very long. MK—7 stays in your system for more than 24 hours so you only have to take it once a day. MK-4 is dosed in milligram amounts while MK-7 is in microgram amounts. (1000 micrograms = 1 milligram). Plus, MK-7 may have added benefits over MK-4 from a heart health perspective.


How much MK-7 do you need? The Japanese get about 200 micrograms of vitamin K2 in the MK-7 form daily. From what we’ve read, between 90 and 200 micrograms per day of MK-7 should be sufficient to get the full benefits.


You’ll find that some vitamin K2 supplements have both MK-7 and MK-4. You probably don’t need both. Stick with MK-7 due to its longer half-life and avoid using a K supplement that also has K1. One that we just started using is Douglas Labs-Vitamin K2 with Menquinone. It has 90 micrograms of MK-7 per capsule.

The Bottom Line?


Vitamin K2 is an overlooked vitamin in our diets. The best way to get vitamins and minerals is by eating healthy, whole foods. If you eat enough vitamin K2 rich foods that’s the best way to go. If not, supplements are an option.




Nutr Metab Cardiovasc Dis. 2009 Sep;19(7):504-10. doi: 10.1016/j.numecd.2008.10.004. Epub 2009 Jan 28.
Vitamin K2 in Bone Metabolism and Osteoporosis. Steven M. Plaza, ND, LAc, and Davis W. Lamson, MS, ND
J Nutr. 2004 Nov;134(11):3100-5.

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.