Vitamin K Should we be taking extra ? Simple question .... ?
Vitamin K ( i.e. K1 ) and vitamin K2 have different functions, in our bodies. Vitamin K1 is found in Greens, there is lots of it there. Vitamin K2 is a bacterial product , that cannot be made by us. Bacteria take K1 and convert it to K2, we use K2 as well , it is an essential nutrient, we would die without it, or suffer very serious disease depending upon the deficiency level.
( Just as Vit B12 is a bacterial product , another essential nutrient which we cannot make ourselves ).
In our gut we have bacteria which should convert some K1 to K2, which we then hopefully absorb. Some gut maladies may, I stress may , not be helpful to that absorption. some other people may , again I stress may, not be absorbing enough.
The function of K2 is to activate certain proteins ( osteocalcin, MGP )to enable calcium transport,( to bones, from tissues ) and very possibly other functions. In fact, the study of K2 is very much in progress, it would be wrong to say that we "know" all about it. There are very many other processes which determine where calcium is deposited, it would be simplistic to think that we know all the mechanism and all the "remedy" to put right any unwanted calcium deposition.
One of the great misconceptions of Vitamin D supplementation is that it "puts up your calcium in your blood." Blood calcium levels are determined by other processes, primarily , your Parathyroid Hormone (PTH) level. it is the PTH level which controls your kidneys and tells them how much Vit D hormone ( 1,25) to make from your background Vit D (25hydroxyD) . It is this Vit D hormone (1,25) which tells your gut cells what percentage of the calcium that you consume they should transfer to your blood. A lot , if not most of the calcium you consume will pass straight through. An adult needs about 200mg of calcium per day to replace that lost by excretion etc. We probably consume about 1.5 grams on average , some people much more, some much less, depending upon your diet. The presence of Vitamin D ( 25hydroxyD ) , in sufficient quantities, allows your body to regulate, under the direction of another hormone which controls your kidneys,( PTH ) what your blood calcium level is. If you are in a state of severe vitaminD deficiency , i.e. less than 25 nmol/L of 25hydroxyD , then you will not be able to extract more calcium from your food, IF YOU NEED IT . If your diet is low in calcium, then the percentage you are able to extract may total less than the 200mg that you require. You body however MUST keep the blood calcium level at a fixed level, the only way to do this , would be to mobilise calcium from the reserves in your body. That is your bones. That is why your bones can become weak, and is one of the reasons why osteoporosis, osteopenia, osteomalacia may occur if you have a deficient level of VitaminD ( 25hydroxyD). As I have explained, your body must maintain a fixed calcium level in your blood, otherwise your muscles , such as heart,also your nerves etc stop working properly. The PTH hormone will rise , instructing your bones to release calcium into the blood, keeping the level where it needs to be.
SO , although vitamin K2 level is very important , it will not be faced with a sudden surge of calcium , in your blood to deal with, if you take vitaminD supplements.
( here I am referring to an average person with no hormone imbalances,or parathyroid problems, not suffering from sarcoidosis or granulomatosis. etc.) These are very rare conditions, but it is the reason why I say that anyone with such problems , also carcinoma etc should be talking to their medical professional caregiver. They know ALL your circumstances.
If you are taking warfarin, to thin the blood, again , be careful if you take Vitamin K , it could, counteract the effect of warfarin. Again, you should be talking to your medical professional.
If you are interested in more of the detail about Vitamin K , here is a link , to a talk , by the director of the vitamin K laboratory at Tufts University.It is a bit technical, however , she gives her opinion about whether we should additionally supplement with Vit K2, towards the end. Her opinion is No.
That is not the final word, however, scientific research is ongoing. In my opinion , at present we cannot say for definate. IF I was a person with inappropriate calcification , arteries, liver,kidney etc, then I would be considering K2 supplementation. I would have expected it to occur, independently of whether I was taking vitaminD supplementation or not.
Sorry this is a bit wordy ... !
Hope it is helpful though
BTBH
PS. Grass fed cows ( not corn fed ) will produce K2, in their milk, concentrated in their butter. It makes a lot of sense, when you consider that such a rich calcium source such as milk will contain those ingredients that are needed to direct calcium to where it is needed. i.e. bones.
Butters such as Kerrygold, and Anchor are made from almost entirely grassfed animals. If you are a butter eater, then it may be advantageous to use them , rather than cheaper corn fed butters. This is not a proven scientific fact, but a maybe a reasonable assumption. Also the bacteria used to ferment Edam cheese produce some K2. If you are a cheese eater, then again, this may be a route to ingest more. This is not a recommendation to eat large extra amounts of fat..!, but possibly a reason to swap some of your current consumption to those above.
The highest concentration of K2 in food , is within a food known as Natto , a fermented soy product. A Japanese food ( I believe ).