Vitamin K2: Study unlocks which forms have higher bioavailability

By Stephen Daniells

- Last updated on GMT

Vitamin K2: Study unlocks which forms have higher bioavailability

Related tags: Vitamin k, Nutrition

Consuming vitamin K2 in its MK-7 form is better for raising levels of the vitamin in serum than K2 in the MK-4 form, says a new study from Japan and the Netherlands.

The results indicate that the “nutritional values of vitamin K2 homologues should be differentiated with regard to bioavailability and efficacy,” ​wrote scientists from J-Oil Mills, Inc., in Japan, University Maastricht in The Netherlands, and Kagawa Nutrition University in Japan in the Nutrition Journal​.

K forms

There are two main forms of vitamin K: phylloquinone, also known as phytonadione, (vitamin K1) which is found in green leafy vegetables such as lettuce, broccoli and spinach, and makes up about 90% of the vitamin K in a typical Western diet; and menaquinones (vitamins K2), which make up about 10% of Western vitamin K consumption and can be synthesised in the gut by microflora.

Menaquinones (MK-n: with the n determined by the number of prenyl side chains) can also be found in the diet; MK-4 can be found in animal meat, MK-7, MK-8, and MK-9 are found in fermented food products like cheese, and natto is a rich source of MK-7.

“Because all vitamin K homologues can be converted to MK-4 in vivo, MK-4 is considered to have specific functions other than gamma-carboxylation of vitamin K-dependent proteins,”​ explained the researchers.

“In this study, we demonstrated that a nutritional dose of MK-7 is well absorbed in human, and significantly increases serum MK-7 levels, whereas MK-4 had no effect on serum MK-4 levels.

Study details

The researchers tested the effects of a single dose of MK-4 (420 micrograms) or MK-7 (420 micrograms) consumed with a standardized breakfast in ten health Japanese women. Results showed that MK-7 was well absorbed and was measurable in serum samples up to 2 days after consumption.

On the other hand, MK-4 was not measured in any of the women at any time, they said.

A second study that used consecutive administration of MK-4 (60 micrograms) or MK-7 (micrograms) for seven days again with ten health Japanese women indicated that MK-4 again did not increase MK-4 levels. On the other hand, MK-7 was found to increase MK-7 levels.

“The current study shows that MK-4 has a poor bioavailability at a nutritional level dose, whereas MK-7 is well absorbed and detectable in the blood at nutritional levels,”​ wrote the researchers.

“In a previous rat study from our group [Vitamins (Japan) 2007, Vol. 81, pp. 377-381], the intake of a nutritional dose of MK- 4 did not increase the MK-4 levels in extrahepatic tissues, whereas MK-7 significantly increased MK-4 in extrahepatic tissues,” ​they added.

“Thus, MK-7 is a better supplier for MK-4 ​in vivo than MK-4 itself.”

Source: Nutrition Journal
2012, 11​:93 doi:10.1186/1475-2891-11-93
“Comparison of menaquinone-4 and menaquinone-7 bioavailability in healthy women”
Authors: T. Sato, L.J. Schurgers, K. Uenishi

Related news

Show more

Related products

show more

Whitepaper: Optimizing immunity with vitamin D

Whitepaper: Optimizing immunity with vitamin D

DSM Nutritional Products | 16-Jun-2022 | Technical / White Paper

With vitamin D science evolving rapidly since the COVID-19 pandemic, our new whitepaper breaks down the latest research on the role of vitamin D in supporting...

Custom Premix Solutions

Custom Premix Solutions

Glanbia Nutritionals | 14-Jun-2022 | Product Presentation

Developing a finished product is complicated.

Meeting the Retail Dietary Supplement Requirements

Meeting the Retail Dietary Supplement Requirements

Gemini Pharmaceuticals | 06-Jun-2022 | Technical / White Paper

Recently, retailers have been requiring additional assurances that the dietary supplement products they offer for sale meet label claims. Brand Owners...

Related suppliers



Posted by Frederick Bach,

The statements inferring that it is sufficient to take in K2-7 in preference to K2-4 are incorrect in my personal experience. I was suffering from serious short-term Memory loss and a terribly stuffy feeling inside my head about where the hippocampus is. O started taking K2-7 for a broken arm. Helped a lot. Did nothing for my head. A year later I broke my leg. My wife found K2-7 AND K2-4 separately. I started with the -7 Dec 2014 still nothing with my head. Then in January I started the K2-4. Wow! The fog in my head lifted and disappeared. My short-term memory returned. I could remember the piano music I just read AFTER I closed the book! Certainly a spooky change. So I let the bottle of K2-4 run out. Symptoms returned. But before I got really bad again I got another bottle of K2-4. Problems went away again. I repeated this one more time. Then I wrote to Life Extension dot org.
They phoned me back. I related my story again. Then they told me they had a paper on that from 2012. I said "So you have known about this for 3 years?" "Yes". Then I said, "Why doesn't the world know about this? I'm telling everybody!" The point is the vegan K2-4 handled by Trophic removed my symptoms while a lot of K2-7 might have helped my bones and skin but didn't do anything for my head. Research that surfaced this year (2016) shows that K2-4 fills in for, or sisters up with, Co-Q10 in the brain especially, and some tissues prefer K2-4.

Report abuse

vegetarian sources

Posted by Donald Spiderman Thomas,

As a vegetarian for 40 years, I am always amazed at the current trend in nutritional science. For so many years, vegetarian sources of many vitamins/minerals were considered inferior.heme iron was superior to non heme iron

Report abuse

Follow us


View more