Saturday, November 22, 2008

Vitamin K2 in Marrow

I'm always on the lookout for foods rich in vitamin K2 MK-4, because it's so important and so rare in the modern food system. I heard some internet rumors that marrow might be rich in fat-soluble vitamins. Google let me down, so I decided to look through the rat studies on K2 MK-4 in which they looked at its tissue distribution.

I found one that looked at the K2 MK-4 content in different tissues of rats fed vitamin K1. Marrow was rich in K2, along with testes. It contains 10-20 times more MK-4 than liver by weight, and more than any of the other organs they tested (serum, liver, spleen, kidney, heart, testes, marrow, brain) except testes. They didn't include values for salivary gland and pancreas, the two richest sources.

If we assume beef marrow has the same amount of MK-4 as rat marrow per weight (I have no idea if this is really the case, but it's probably in the ballpark), two ounces of beef marrow would contain about 10 micrograms MK-4. Not a huge source, but significant nevertheless.

Bone marrow was a prized food in many hunter-gatherer societies. Let's see what Dr. Weston Price has to say about it (from Nutrition and Physical Degeneration):
For the Indians living inside the Rocky Mountain Range in the far North of Canada, the successful nutrition for nine months of the year was largely limited to wild game, chiefly moose and caribou. During the summer months the Indians were able to use growing plants. During the winter some use was made of bark and buds of trees. I found the Indians putting great emphasis upon the eating of the organs of the animals, including the wall of parts of the digestive tract. Much of the muscle meat of the animals was fed to the dogs. It is important that skeletons are rarely found where large game animals have been slaughtered by the Indians of the North. The skeletal remains are found as piles of finely broken bone chips or splinters that have been cracked up to obtain as much as possible of the marrow and nutritive qualities of the bones. These Indians obtain their fat-soluble vitamins and also most of their minerals from the organs of the animals. An important part of the nutrition of the children consisted in various preparations of bone marrow, both as a substitute for milk and as a special dietary ration.
Here's a bit more about these same groups, also from Nutrition and Physical Degeneration:
The condition of the teeth, and the shape of the dental arches and the facial form, were superb. Indeed, in several groups examined not a single tooth was found that had ever been attacked by tooth decay. In an examination of eighty-seven individuals having 2,464 teeth only four teeth were found that had ever been attacked by dental caries. This is equivalent to 0.16 per cent. As we came back to civilization and studied, successively, different groups with increasing amounts of contact with modern civilization, we found dental caries increased progressively, reaching 25.5 per cent of all of the teeth examined at Telegraph Creek, the point of contact with the white man's foods. As we came down the Stikine River to the Alaskan frontier towns, the dental caries problem increased to 40 per cent of all of the teeth.
Evidently, the traditionally-living groups were doing something right.


Peter said...

Hmm, another Terminator failure then...


Unknown said...

Very good source are also brains. In beef it probably vary alot with fodder (consider butter variation).


Stephan Guyenet said...


Yes indeed! Although I have yet to find a farmer who's willing to sell me brain here.

Unknown said...

I find it very interesting, that when our cat catches a mouse, it eats only the head (brains) and usaly leaves everything else intact (a little bizarre scene). Our cat usally has plenty of food and I guess brains are just nutrition supplement :). Brains are rich in omega 3, K2 MK-4 and at least some D3. Perfect nutrition supplement for balancing weak link in modern foods.

Stephan keep on good work.


Stephan Guyenet said...


Very interesting! I've noticed that domestic cats do tend to go for the organs and leave the muscle behind.

Anna said...

My younger cat is an expert mouse hunter. If she eats her prey, it's the head she goes for, leaving the body. Then the older, slower cat finishes the remainder off. Neither ate prey (that I know of) until they were on a raw meaty bones diet at home. The taste of meat must have awakened their carnivorous instincts after suffering the effects of dry kibble for too long.

Unknown said...

During Thanksgiving one of my favorite parts of the traditional meal is stuffing with giblets, which I guess isn't too unhealthy after all (except for the bread or croutons).

Bryan - oz4caster said...

Funny, I was just looking at some food photos from a restaurant in France, where they served big marrow bones with dinner. I wish restaurants here in the U.S. would serve meat with marrow bones on the side like that :)

I remember Anthony Bourdain saying that his favorite food is bone marrow. Maybe that's what protects him from all the other junk he eats :)

Lee said...

How about egg yolks as a source of K2? I have seen some very low amounts reported but Chris Masterjohn has larger amounts listed:

Egg Yolk (Netherlands) 32.1
Egg Yolk (United States) 15.5

Hopefully, these are nearer the truth for good quality free range chicken eggs.

Stephan Guyenet said...


Those figures are for 100g egg yolks I believe, which is about 1/4 lb. That's about 6 yolks. Still, it's a meaningful source of K2. I suspect that true pastured eggs would be substantially higher than either of those numbers. They show that the amount can vary by at least 2-fold.

Unknown said...

I know this anecdote is late but when I eat real, pastured beef marrow, I feel totally satisfied in a way no other food can provide. It's not surprising, given that we've been eating marrow since before we were human. Unless I'm in ketosis, having a very lean week, or lifting heavy, I eat my food too quickly, as I have my whole life. The instant marrow touches my tongue I slow down. Perhaps some of this is due to my celiac disease. Be warned that feedlot marrow is rather disgusting - Steffanson called it "insipid" - while lightly cooked pastured marrow is delicate and almost fruity.

PS - Stephan, you may find lamb's brain at halal markets.

Unknown said...

Sorry this anecdote is late. When I eat real, pastured beef marrow, it satisfies me in a way no other food can. Unless I'm in ketosis, having a very lean week, or lifting heavy, I eat my food too quickly, as I have my whole life. The instant marrow touches my tongue I slow down. Perhaps some of this is due to my celiac disease. Then again, we have been eating marrow since before we were human. Be warned that feedlot marrow is rather disgusting - Steffanson called it "insipid" - while lightly cooked pastured marrow is delicate and almost fruity.

PS - You can often find lamb's brains at halal markets.

Zoli said...

So what are the Vitamin K2 (MK-4) figures for brains and testicles? Also do these organs - or any others - contain any MK-7?

In my corner of the world you can easily buy pork brains and turkey testicles, and they aren't expensive.

So I am more than willing to incorporate more of these into my diet if they are worthy of it.

DS said...

Where do you get the idea that pancreas and salivary glands are high in k2?

I briefly tried to look for data on pubmed and could not find anything.

Could you point me to the data?

If there is no data and you are making an educated guess, I would say: despite the fact k2 is important in insulin secretion from the pancreas and for dental mineralisation (which depends on the salivary glands); it may be a bit too much of an assumption to say that these organs must be high in k2. The effect of k2 on the function of these organs could be indirect, without the k2 having to be present at the site.

Kindest Regards,