Menaquinone-7 supplementation and vitamin K protein activation in healthy adults
What it found
Daily menaquinone-7 capsules at doses around the recommended amount improved the activation of bone and artery proteins in healthy people.
Blood clotting activity stayed the same across all doses tested.
What they found
Studies in people
Bone protein activation
Doses around the recommended daily amount significantly lowered the inactive form of a bone protein called osteocalcin. Lower doses below that amount did not change these levels compared to the dummy capsules.
Artery protein activation
Higher doses also reduced the inactive form of a protein found in artery walls and cartilage. This suggests better vitamin K status outside the liver at those dose levels.
Blood clotting unchanged
Taking menaquinone-7 at any tested dose did not change two measures of blood clotting activity. Start and end values for clotting remained about the same across all groups.
Blood levels rose with dose
Menaquinone-7 levels in the blood went up as the capsule dose increased. Compared to the dummy group, this rise became clear starting at the 90 mg daily dose.
Other findings
Capsule ingredients
The supplement capsules held oils from linseed and natto, along with potato starch, sunflower oil, a wax coating and a colouring agent. Only the amounts of the two main oils varied between the different dose strengths.
What the authors conclude
- They conclude that daily menaquinone-7 at doses near the recommended amount measurably improves the activation of proteins outside the liver.
- They state that menaquinone-7 does not raise the risk of unwanted blood clots in people who are not taking blood-thinning medicine, even above the recommended amount.
- They advise that more research is needed to find out if this protein improvement actually protects against age-related diseases.
How it was done
Normally, 10 to 40 percent of certain bone and artery proteins remain only partly activated because of low vitamin K intake. The authors wanted to see how different amounts of extra menaquinone-7 affected this activation, and whether it changed blood clotting.
Forty-two healthy Dutch men and women aged 18 to 45 took part. They were split into seven groups to take either dummy capsules or menaquinone-7 capsules daily for 12 weeks. The active doses ranged from 10 to 360 mg per day.
What it can’t tell you
- This trial measured changes in blood proteins, not actual disease outcomes like fractures or heart problems. It cannot show whether taking menaquinone-7 prevents illness over time.
- Only 42 people took part, so the results might not apply to everyone, especially older adults or people with existing health conditions.
Who paid
- Authors work at
- Maastricht University, The Netherlands
The paper
- Title
- Low-dose menaquinone-7 supplementation improved extra-hepatic vitamin K status, but had no effect on thrombin generation in healthy subjects
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Theuwissen E, Cranenburg EC, Knapen MH, et al (2012). Low-dose menaquinone-7 supplementation improved extra-hepatic vitamin K status, but had no effect on thrombin generation in healthy subjects. The British journal of nutrition. doi:10.1017/S0007114511007185Free full textPubMed 22289649DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error