[petelamana (OP)]

Hello,

I make no pretense about knowing very much about the medical arts, so I am turning to the collective wisdom of The Naked Scientist.

I read that most of us in the "developed" world are vitamin K2 deficient. 
     → Is this true?
     → What does vitamin K2 do?

Thank you.

[Colin2B]

Sellers of chemical supplements will always tell you we are deficient in something, which only their products will supply. I havent seen evidence of any deficiency, although the switch away from dairy products may cause a problem for some unless they provide an alternative source in their diet.

Vitamin K2 is a collection of menaquinones (MKs) that mostly originate from bacterial synthesis.

Various bacterial species used as starter cultures for food fermentation are known to synthesize MK and fermented food are a good source of vitamin K2 - sauerkraut, natto, miso. In the Western diet, dairy products are one of the best known and most commonly consumed group of fermented products, but whole milk, butter, eggs are also a good source. K1 can also be converted to K2 by gut bacteria, but it’s not clear how much is absorbed.

K2 is used to activate proteins that regulate where calcium ends up in the body and may  play a part in whether calcium is deposited in the arteries and bones.
Most studies that have investigated the relationship between dairy and bone health have shown a benefcial effect of dairy consumption, even if the reason for this link is still unclear. After many years of focusing on calcium as the beneficial element recent evidence suggests that other macro‐ and micronutrients present in milk and dairy products, play an important role in this health outcome - including D, A, K2 etc.
The results of observational studies have shown an association between higher dietary menaquinone consumption and less calcification, decreased risk of coronary heart disease (CHD), CHD mortality, and all-cause mortality. The results of a Dutch prospective cohort study suggested that of all MKs the long-chain menaquinones (MK‐7 to MK‐9) have the most beneficial effects on cardiovascular disease. These results must be interpreted with caution, because validated biomarkers for single MK intake are missing.

 There is no evidence that consuming K2 will remove calcium deposits from the arteries and in terms of prevention it is generally better to obtain vitamins from diet than chemical supplements, this is particularly true in calcium regulation where a whole range of inter-related nutrients are involved.

[Colin2B]

I should have also said that both K vitamins are involved in blood clotting - the K comes from the German for coagulation. Those useing supplements should note the experience of an Ayrshire man with a mechanical heart who was on anticoagulants, who was hospitalised after his eating too many Brussels sprouts - which contain lots of Vitamin K and counteracted the effect of his medication.

[evan_au]

I know someone who was on anticoagulants, and the doctors were worried about the high doses she was receiving.

As I recall, it turned out that her high intake of tabbouleh was blocking with the anticoagulants, due to the large intake of vitamin K.