The People's Perspective on Medicine

What Can Vitamin K2 Do for You?

Scientists are studying what vitamin K2 can do. It may help build bone and reduce calcification of major arteries, but research is ongoing.
Cheeses dairy food

The early 20th century was the Golden Age of vitamin research. Scientists identified previously unknown compounds and named them in order: vitamins A, B, C and so on. The B vitamins turned out to be a family: vitamin B1, vitamin B2, vitamin B3, for example, all the way through vitamin B12. A Danish scientist, Henrik Dam, identified a fat-soluble compound critical for blood clotting in 1929. The German journal that published his research termed the discovery Koagulationsvitamin, aka vitamin K. Most people are unaware that in addition to vitamin K1, which controls clotting, scientists are also studying vitamin K2 and vitamin K3. What does vitamin K2 do?

Will Vitamin K2 Do Anything for Your Health?

Q. I became interested in vitamin K2 about a year ago when my nurse practitioner told me to take it for my joints. Curious, I started researching it to see what it could do. And boy, what it can do! I take it every day now for general overall health and my joints.

I found two clinical trials on vitamin K2 with very encouraging results. Vitamin K2 supplementation increased bone density in older women in one trial (Osteoporosis International, July 2007). In another trial it reduced stiffness in women’s arteries (Thrombosis and Haemostasis, May 2015). Granted, women took supplements daily for three years to achieve these effects, but they are impressive results nonetheless.

What Does the Research Show?

A. Thank you for highlighting research on this compound. A review of the medical literature on vitamin K2 (menaquinone) suggests that it may play an important role in getting calcium into bones and keeping it out of arteries (Frontiers in Cardiovascular Medicine, Feb. 5, 2019).  That could help explain both benefits you describe. Fermented foods such as cheeses or natto provide vitamin K2 in the diet. 

Danish investigators are currently conducting a trial of menaquinone-7 supplements to see if they can alleviate aortic valve calcification (BMJ Open, Aug. 23, 2018). That would certainly be a significant health benefit. However, another recent study found that such supplements might actually increase calcification of blood vessels (American Journal of Clinical Nutrition, online Aug. 6, 2019).  The researchers didn’t report any adverse effects, but it seems we still need more clinical trials to understand what this compound can and cannot do.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies. .
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  • Knapen MHJ et al, "Vitamin K2 supplementation improves hip bone geometry and bone strength indices in postmenopausal women." Osteoporosis International, July 2007.
  • Knapen MH et al, "Menaquinone-7 supplementation improves arterial stiffness in healthy postmenopausal women. A double-blind randomised clinical trial." Thrombosis and Haemostasis, May 2015. doi: 10.1160/TH14-08-0675
  • Wasilewski GB et al, "The bone-vasculature axis: Calcium supplementation and the role of vitamin K." Frontiers in Cardiovascular Medicine, Feb. 5, 2019. DOI: 10.3389/fcvm.2019.00006
  • Lindholt JS et al, "Effects of menaquinone-7 supplementation in patients with aortic valve calcification: study protocol for a randomised controlled trial." BMJ Open, Aug. 23, 2018. DOI: 10.1136/bmjopen-2018-022019
  • Zwakenberg SR et al, "The effect of menaquinone-7 supplementation on vascular calcification in patients with diabetes: A randomized, double-blind, placebo-controlled trial." American Journal of Clinical Nutrition, online Aug. 6, 2019. DOI: 10.1093/ajcn/nqz147
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I have read that MK4 is used as a treatment for osteoporosis in Japan – 45mg/day.

I believe that adding 90 mcg. vit K2 as MK7 form, in combination with resistance exercise, helped improve my steroid-induced postmeno osteoporosis.

DEXA results are improving, my hips are now just osteopenic, docs are scratching their heads because this should only have happened with the alendronate or Prolia that were forcibly recommended.

I continue to take Prednisone daily, reversal “just does not happen” — says my rheumatologist — in that circumstance. ;)

How do vitamin K supplements affect blood clotting? I wonder it is safe to take supplements without fear of getting blood clots?

Vitamin K1 affects clotting. In theory, vitamin K2 does not.

Didn’t say what foods chain this vitamin. Which ones do?

Natto, dark greens such as collards, turnip greens, kale and spinach, broccoli, edamame, canned pumpkin, pomegranate juice, okra. Also cheese and egg yolks. Here’s a long list:

After surviving two heart attacks, my search for a holistic cardiologist lasted three long years, during which time I visited four different cardiologists, all of which knew little to nothing about natural products to improve heart health. Finally, I found a cardiologist who had gotten tired of treating heart disease and began a new career in “Preventing” heart disease. It was under his great care that I was told to take vitamin K-2. Today, I am regaining my strength. He also suggested Co Q-10, Ionic Magnesium and Potassium. Today I control angina far faster using Ionic Magnesium than the $1,200 per month drug Ranexa. So tragic the established, drug industry has such a hold on prevention and treatment of disease.

I also did some research on Vitamin K2 and liked what I read. So I have been taking one supplement every day for the past 3 years. I did not want to go on the osteoporosis meds. Glad I found K2 and appreciate your article on this. I feel I am on the right track.

Help me understand why people who take warfarin need to watch their Vitamin K and others on new blood thinners don’t. Now I see there are different vitamin Ks. So what is a person to do since most doctors are not trained in nutrition. DO they really know the effects of medicine?

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