Vitamin K-2 (MK-7, from Natto)

An essential vitamin for bone and cardiovascular health, derived from fermented soybeans.

Also known as: Menaquinone-7

other Names
Menaquinone-7, K2-MK7
primary Benefits
Bone health, cardiovascular health, blood clotting
common Dose
90-120 mcg daily
best Form
MK-7 from natto
timing
With a meal containing fat
safety Rating
Very safe, with no known toxicity

Overview

Vitamin K2 in the form of MK-7 is a highly bioavailable form of Vitamin K. It is naturally found in high amounts in natto, a traditional Japanese dish of fermented soybeans. Vitamin K2 plays a crucial role in directing calcium to the bones and away from the arteries, thereby supporting both skeletal and cardiovascular health.

Key Benefits

Promotes Bone Health

Vitamin K2 activates osteocalcin, a protein that helps bind calcium to the bone matrix, improving bone density and reducing fracture risk.

Supports Cardiovascular Health

It activates Matrix GLA protein (MGP), which helps prevent calcium from depositing in the arteries, a major risk factor for heart disease.

Aids in Blood Clotting

Vitamin K is essential for the synthesis of several proteins involved in the blood clotting cascade.

Dosage & How to Take

The optimal dose of Vitamin K2 MK-7 can vary, but a daily intake of 90-120 mcg is generally recommended for adults.

PurposeDoseNotes
General Health90-120 mcg/daySufficient for most adults.
Bone Health Support180-360 mcg/dayHigher doses may be beneficial for individuals with osteoporosis.

Best Time to Take

Take with a meal that contains fat to enhance absorption.

With or Without Food

Yes, with a fatty meal.

Forms & Bioavailability

FormAbsorptionBest ForNotes
MK-7 from NattoHighOverall healthThis is the most bioactive and long-lasting form of Vitamin K2.
MK-4LowSpecific applicationsHas a much shorter half-life than MK-7 and requires multiple daily doses.

Side Effects & Safety

Common

  • None at recommended doses

Rare

  • None known

Contraindications

  • Individuals taking blood-thinning medications (e.g., warfarin) should consult their doctor before supplementing with Vitamin K.

Interactions

Warfarin (Coumadin)Important

Vitamin K can interfere with the effectiveness of warfarin. Dose adjustments may be necessary.

Scientific Research

2013Osteoporosis International

Three-year low-dose menaquinone-7 supplementation helps decrease bone loss in healthy postmenopausal women

Supplementation with 180 mcg of MK-7 per day significantly improved vitamin K status and decreased the age-related decline in bone mineral density.

2015Atherosclerosis

Menaquinone-7 supplementation to reduce vascular calcification in patients with coronary artery disease

MK-7 supplementation was associated with a decrease in the progression of coronary artery calcification.

Food Sources

Natto, hard cheeses, egg yolks, butter

Frequently Asked Questions

Medical Disclaimer

This content is for educational and informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare professional before starting any supplement regimen, especially if you have pre-existing health conditions or are taking medications. The statements on this page have not been evaluated by the Food and Drug Administration.