Vitamin K and bone health

Recent research has revealed that vitamin K plays a vital role in maintaining healthy bones and arteries by keeping calcium in the bones and out of the arteries.

It matters greatly, however, which vitamin K you use as a supplement to prevent or treat osteoporosis.

The majority of vitamin K research to date has focused on vitamin K1, the dominant dietary form of vitamin K that occurs in green, leafy vegetables. Yet it appears that vitamin K2, which occurs in organ meats, egg yolks, and dairy products, is a more important inducer of bone mineralization in human osteoblasts (bone-building cells) than vitamin K1.

•    Vitamin K1 (5 mg) has been shown not to protect against age-related decline in bone mineral density.
•    Low dose vitamin K2 (45mg daily) has been shown to not only prevent bone loss but also to help maintain bone health in postmenopausal women.

The Japanese long ago recognized the power of vitamin K2 to maintain or restore bone health. In certain regions of Japan, a staple dish called natto or fermented soybean, frequently eaten several times a week, is uniquely rich in vitamin K2.

Two main forms of vitamin K

  • Vitamin K1 (phylloquinone or phytonadione) which is found in green leafy vegetables including lettuce, broccoli, and spinach and makes up about 90% of the vitamin K in a typical Australian diet.
  • Vitamin K2 (menaquinones) are also made by bacteria in the gut. Vitamin K2 does not strictly speaking qualify properly as a vitamin as it can be made from bacteria, however, it shows how incredibly important it is to have a healthy microbial system in our intestines.

Healthy gut

Conditions or drugs that impair fat absorption will also impair the absorption of Vitamin K, especially antibiotics. In their effort to rid foreign bacteria, antibiotics destroy the normal intestinal flora needed for Vitamin K synthesis, causing a deficiency of the vitamin.

Osteoarthritis, rheumatoid arthritis and heart disease

Vitamin K2 deficiency has also been found in the bones of patients with osteoarthritis, so it is likely that K2 supplementation may also help this condition.

For patients with established rheumatoid arthritis treated with alendronate, coadministration with vitamin K2 may provide further benefits.

Vitamin K2 also protects against heart disease.


Vitamin K2 is very safe, however, there has been a case published where a patient with a heart condition experienced mild low blood pressure when vitamin K2 was combined with his heart medication. Patients taking warfarin need to be carefully monitored if taking vitamin K2.
Vitamin K is required by the human liver to manufacture blood-clotting proteins. This is the basis for administering the vitamin K-blocking drug, warfarin to people who are at risk for blood clot formation.


The lowest effective dosage of vitamin K is around 50 micrograms. Although dosages as high as 1000 microgram have been used. We recommend starting out with 100 microgram.

We also recommend combining vitamin K2 with vitamin D and a quality mineral supplement both to build strong bones and in the treatment of osteopenia or osteoporosis, as well as for supportive treatment of osteoarthritis and rheumatoid arthritis.