Vitamin K Bone Health and Supplementation

I was not planning to make any more posts on this site until I had finished all of the key informational pages such as the ones on calcium and osteoporosis medications. However, during my research into the Vitamin K and Osteoporosis key page, I hit on something that I found quite disturbing. I would normally give a little overview of a subject before diving into it (I will give some more information further down this post) but I will get straight to the point:

  • Japanese research (see below) into the use of Vitamin K2 as an osteoporosis treatment use a daily treatment of 45 mg (milligrams) of the MK-4 form.
  • Most vitamin K supplements sold are at a dosage of 45mcg (µg / micrograms) of the MK-7 form.

It is therefore clear that there are two major problems associated with the use of vitamin K for the treatment of osteoporosis.

  1. Supplements are sold at a dosage that is 1000× less than what is used in the Japanese studies. The thing that I like about this the least is that the manufacturers/sellers of vitamin K2 supplements make use of the number ’45’. This is deliberately misleading.
  2. Supplements come in the form of MK-7 and not MK-4. This has two major problems (there is a reason why the Japanese scientists use MK-4 and not MK-7):
    1. MK-4 is rapidly absorbed into the system.
    2. One third of all people do not have the genetics that allow for the efficient synthesis of Vitamin K2 MK-7. This can lead to a build-up of the isoprenoid in the body; many people are unable to tolerate prolonged use of this form of supplement without suffering side-effects.

Vitamin K Sources

Now that I have got the main problem that I have with vitamin K2 MK-7 supplements out of the way I will discuss the vitamin a little further. Firstly there are 5 known vitamers of vitamin K (1,2,3,4,5). K1 is found in the chloroplasts of plants, and plays an active role in the photosynthesis process. K2 is produced by bacteria; mainly by intestinal bacteria in humans. The other three vitamers are synthetic, and have been shown to be toxic in humans. Here are a few take home messages:

  • The K1 form of the vitamin is readily converted by bacteria in the gut to K2.
  • K2 MK-4 can be obtained in certain foods such as cheese and Pâté.
  • K2 MK-7 is produced by bacteria in the creation of Nattō  (Bacteria fermented soybeans).

As the body is able to convert K1 to K2 it is possible to incorporate an adequate supply of the vitamin through diet alone. This will require a love for green leafy vegetables such as spinach, kale and Brussels Sprouts. Vitamin K2 in the MH-4 form can also be incorporated into the diet by eating cheese, Duck/Goose liver Pâté, and bacon; unfortunately the amount of MH-4 in these products is fairly low: see vitamin K Rich Foods List. If you are not a fan of eating a lot of leafy vegetables everyday you may consider taking a liquid vitamin K2 MH-4 supplement.

Liver Pate is a great source of Vitamin K
Pate photograph by Smabs Sputzer (1956-2017); CC.

Vitamin K for Osteoporosis Treatment Requirements

There has been a lot of research into the use of Vitamin K with regards to bone health, and it is currently used for the treatment of osteoporosis in Japan. Meta analysis findings suggest that the risk of osteoporotic related hip fractures could be reduced by as much as 77%, vertebral fractures by 60%, and non-vertebaral fractures by as great as 81%. All of these studies, with the exception of one, used a dosage of 45mg vitamin K2 MK-4 (the exception used a dosage of 15 mg).

One of the studies also demonstrated that there was a statistically significant increase in bone strength, in comparison to the placebo. Further studies have demonstrated that 1mg of vitamin K1 daily can reduce the circulating levels of under-carboxylated osteocalcin; this demonstrates the effectiveness of the K1 form of the vitamin–higher levels of under-carboxylated osteocalcin are found in postmenopausal women–and it is predictive of fracture risk. An interesting epidemiological study reported that elderly people who consumed 250 µg of Vitamin K daily had a 65% lower risk of reporting a hip fracture over a seven year analyses period, in comparison to those with a daily intake of around 50 µg.

So the take home from the research:

  • 1 mg daily supplementation of Vitamin K1 is biologically active in the body and able to lower under-carboxylated osteocalcin.
  • People who consume 250 µg of Vitamin K2 per day have a lower incidence of hip fractures than those who consume just 50 µg
  • A 45 mg dose of Vitamin K2 in the MK-4 form can increase bone strength over a three year period
  • A 45 mg dose of Vitamin K2 in the MK-4 form decreases the risk of vertebal (60%); hip (77%); and non-vertebaral fractures (81%) to significant levels.

Vitamin K recommendations

For preventative measures:

  • Although the AI of vitamin K is 90 µg for women, and 120 µg for men, it seems that there is a benefit to bone health by consuming 250 µg on a daily basis. This amount can be incorporated into the diet by consuming broccoli, spinach and other green vegetables on a daily basis. The addition of cheese and liver Pâté is also recommended.
  • People over the age of 65 may also wish to take daily multivitamin supplements (that contain vitamin K).

If you have been diagnosed with osteopenia or osteoporosis

  • Follow the above recommendations.
  • Do not take Vitamin K supplements in the form of MK-7
  • Consider the use of 15 to 45 mg Vitamin K2 MK-4 supplements (the majority of research uses a 45 mg dosage).
  • There are presently no reported effects associated with high levels of Vitamin K2 consumption–though little research has been done into long term effects of supplementation at these levels.
  • As the MK-4 isoprenoid is naturally produced by the body, and the MK-7 is not, it may be presumed that there are less likely to be side-effects associated with taking this form. As with any treatment, if you do suffer any side effects then stop taking supplements immediately.

Costs and Sources of Vitamin K2 MK-4

One of the reasons that the MK-7 form of vitamin K is found in most supplements is due to manufacture cost. Indeed, MK-4 supplementation at the levels thought to combat osteoporosis, and increase bone health is not a cheap option. The supplement is usually taken in liquid form (3 x 15 mg doses), and supplied in a 1 ml quantity. If taken at a dosage of 45 mg then a bottle is likely to last for around three weeks at a cost of around £70 to buy in the United kingdom and $60 in the United States.

For those considering taking K2 as a preventative measure, it is possible to get a weaker vitamin D/K2 liquid mixture. As 250 µg of K2 MK-4 is thought to be beneficial for bone health, costs are much lower.

The supplements can be bought in the right form from Amazon:


Vitamin K2, 1 fl oz (30 ml) – Thorne

Vitamin D/K2 (1oz – 30ml) – Thorne


Thorne Research – Vitamin K2 Liquid – 1 fl oz

Thorne Research – Vitamin D/K2 Liquid – 1oz

I hope that this article has been hopeful for you, and has cleared up any questions that you have on the use of vitamin K with regards to bone health.