This post relies heavily on the excellent book by Kate Rheaume- Bleue entitled “Vitamin K2 and the Calcium Paradox: How a Little-Known Vitamin Could Save Your Life”(1)
As indicated in Blog 21, the fermented product prepared from soya is a particularly good source of Vitamin K2 (VK2) which is readily available in certain parts of Japan. However this is not easily obtained in Europe or the USA and in any case it has an acquired taste and would probably not be acceptable to those who have not been brought up on it. In practice therefore the non-Japanese will be dependent on two main sources, namely:
- Products from grass-fed animals
- Cheese.
Animals have the ability to convert Vitamin K1 (VK1) which is present in green chlorophyll containing plants into VK2. For many farm animals this is provided by grass in their habitual diet. However most of the modern-day animal production systems do not include access to grass with the result that the amount of VK2 produced can be severely limited. In addition even when there is a high content of VK2 present as in meat or milk produced from grass-fed animals, many people still miss out. This is because they are attempting to comply with the dietary recommendations which advise that saturated/animal fats should be avoided or reduced. As a consequence they trim the fat from meat and choose semi-skimmed milk. Unfortunately this means that they also reduce the intake of VK2 which is present in the fat.
The other main source is cheese because the VK2 is produced by the bacteria during the cheese fermentation. In the EPIC study on cancer described in Blog 21 it was found that almost half of the VK2 intake was from cheese and that the difference in cheese consumption was responsible for much of the difference in intake between individuals. It was also noteworthy that there was an inverse relationship between cheese intake and cancer incidence. The researchers concluded that:
“the findings of our study imply that the consumption of cheese may have a beneficial effect with respect to cancer, particularly prostate and lung cancer in men”(2)
The possibility that there are other factors present in cheese which help to control cancers cannot be ruled out. Certainly there is no evidence to support the recommendation that cheese, especially full fat versions should be avoided. In fact it is probably the reverse.
Other good sources include goose liver pate, egg yolk, fresh meats especially from animals with access to grass. Cheese, especially Gouda and Brie, is a very good source. The presence of VK2 in these products may help to explain why the incidence of heart disease in countries such as France is relatively low.
It is important to appreciate that there are minor differences in the chemical structures of the VK2 produced by animals (referred to as MK 4) and that produced during cheese fermentation (referred to as MK 7). The MK 7 has a longer half-life than the MK4 which means that they provide higher and more stable VK2 levels in blood than foods which contain MK 4. It also has the advantage that a relatively low dose is effective.
For those who wish to take supplements therefore it is preferable to select products which contain the MK 7 rather than MK 4. Unfortunately the authorities are not up-to-date with devising “Recommended Daily Intakes” so complying with them will not necessarily ensure an adequate intake. Kate Rheaume-Bleue advises that a daily intake of 120 micrograms for the majority of people but for menopausal and post-menopausal women it may be advisable to take 240 micrograms or more. She also points out that the MK 7 is prepared from natto and may not be suitable for those who are allergic to soya. Supplements in the form of a soft gel or oil-based liquid suspension will be more efficiently utilised than those which are hard gels or tablets.
One final point is that an adequate supply of VK2 is particularly critical for anyone already taking supplements or calcium or vitamin D. For these nutrients to be utilised effectively by the body it is essential to have ample VK2. Otherwise there is a real danger that the calcium and the Vitamin D will do more harm than good.
REFERENCES
- K Rheaume-Bleue (2012) Vitamin K2 and the Calcium Paradox: How a Little-Known Vitamin Could Save Your Life. John Wiley & Sons Canada
- K Nimptsch et al (2010) American Journal of Clinical Nutrition 91(5) pp1348-1358
Verner, I admire your work on this blog. In the case of Vitamin K2, I think the MK-4 form, the form that mammals make and use, is getting short shrift. The doses have to be frequent and larger than with MK-7 in order to be absorbed and used by all the tissues in the manner of endogenous MK-4, but this is not a defect. I notice greater cognitive clarity and more testosterone, so this is more than just calcium out of the arteries and into the bones. MK-4 seems to increase one’s protein requirement somewhat as more and more bodily systems get repaired properly. Personal experimentation with MK-4 is now the only way to go because there is little research on things like why the endocannabinoid system seems to work better after a course of MK-4 supplementation. Although you can feel these things, unfortunately you cannot yet read about them in scientific research.
Thank you for this. I was not aware of this. V
Verner, check out this review of MK-4 (mostly) and the nervous system: http://advances.nutrition.org/content/3/2/204.full .
It does make sense for us aging humans to supplement MK-4!
Jim
I also wanted to say that I feel the brain effects when supplementing 4 mg. of MK-4 three times a day. At this dosage, I need to increase protein to about 2 grams per kg/day in order to avoid side effects of visual “floaters” and little periodontal issues such as tiny areas of gum soreness. So, I am assuming that there is some blood/brain barrier resistance to oral MK-4, that it increases protein requirements by up-regulating tissue repair, and that my endogenous MK-4 production is inadequate or else I would get no beneficial effect from supplementation. Perhaps my endogenous production would resume if I ate prodigious amounts of rabbit food, but aging seems to reduce endogenous MK-4 production.
Hi Verner.
You can usually get Natto in Asian supermarkets and stores.
Contrary to your statements, Natto is quite palatable.
An acquired taste to a degree but certainly not hard to get used to and better than supplements.
Take it with soy and green onion.
Cheers.
Thank you. I will take your word about the taste. Must try to find it next time I am in Bradford. V