151 Vitamin K2 Supplementation [6 February 2012]

As discussed previously, there are two different vitamin Ks – K1 and K2. K1 – the clotting factor – should be adequate in our diets if we eat lots of leafy green vegetables. K2 – the important one for preventing both atherosclerosis and osteoporosis – is more likely to be deficient and is difficult to get in our modern diet, so supplementation is required.

There are two main forms of vitamin K2 – MK4 and MK7. Both forms work well at ensuring our dietary calcium goes into our bones and teeth instead of our arteries. But there are critical differences which affect their suitability as supplements.

MK4 is the form made by mammals and is found in goose liver, egg yolk, butter and fat from grass-fed birds and animals. It lasts only a few hours in the body so needs to be taken in divided doses throughout the day. A therapeutic dose for bone and artery health is 45g (4,500mcg). Unfortunately Health Canada’s regulations haven’t kept up with the latest research and the largest allowed dose of any K vitamin in a supplement is 120mcg. While this is an appropriate limit for K1, for MK4 you would need to take nearly 40 pills a day.

Fortunately MK7 comes to our rescue. The MK7 form of K2 is produced by certain bacteria and is the form found in natto. It lasts several days in the body so needs to be taken only once a day. And only 1 or 2 of the 120mcg capsules fulfils our daily requirement, so is perfect for Canada.

Anyone taking an anti-coagulation prescription (e.g. Warfarin) is advised to avoid dietary sources of K1 and all K supplements. As well as controlling K1, Warfarin also inhibits K2, increasing risk of osteoporosis and atherosclerosis. Fortunately a small daily dose (less than 50mcg) of MK4 (not MK7) will ameliorate some of the K2 deficiency side effects without interfering with its blood thinning effect. Talk to your doctor before attempting this if you are on an anticoagulant prescription.

Source: Vitamin K2 and the Calcium Paradox by Kate Rheaume-Bleue, Bsc. ND, John Wiley & Sons, 2012.

For more information on this or other natural health topics, stop in and talk to Stan; for medical advice consult your licensed health practitioner.