vitamin · for high blood pressure
Vitamin K2
Keeps calcium out of artery walls, which helps them stay springy rather than stiff.
Say that in clinical terms
Activates MGP to prevent arterial calcification and improve arterial elasticity, reducing systolic and diastolic pressure.
How strong is the research?
A 24-week trial in 96 dialysis patients found no real change in artery stiffness.
4 papers read, 1 supporting, 1 against.
Who was studied: Studied in healthy postmenopausal women who started with low vitamin K.
How much to take
daily
180–360 mcg
Contraindicated with warfarin. Higher doses more effective for vascular health.
Before you take it
- No Tolerable Upper Intake Level (UL) has been established for any form of Vitamin K, including MK-7, by the Food and Nutrition Board; the NIH ODS states no adverse effects from food or supplemental Vitamin K have been reported in humans or animals.
- Warfarin/VKA contraindication: Vitamin K2 (MK-7) directly antagonizes the anticoagulant effect of vitamin K antagonists (warfarin, acenocoumarol, phenprocoumon) by restoring carboxylation of vitamin K-dependent clotting factors. MK-7's 72-hour biological half-life produces sustained, cumulative INR interference; even approximately 10 mcg/day has caused clinically significant INR reductions in approximately 40% of anticoagulated patients in dose-response research. MK-7 supplementation is considered contraindicated in patients on VKAs.
- Pregnancy: NIH ODS lists an Adequate Intake of 90 mcg/day for pregnant women without specific warnings for standard supplemental doses; however, high-dose MK-7 supplementation data in pregnant women has not been systematically characterized.
When to take it
Best taken: with food
What we make of it
The trial measured artery stiffness. Blood pressure only moved in an after-the-fact subgroup.
The detail
The study set out to measure how stiff arteries were, not blood pressure. A blood pressure drop turned up only when the data were re-cut afterwards, in postmenopausal women who had stiff arteries to begin with — which is a hypothesis to test, not a finding.