What are the best foods for Vitamin K2?
One of the newer focuses on nutritional health in the past 10 years has been on Vitamin K2 (not to be confused with Vitamin K1 that has a role in blood clotting).
Scientists continue to uncover more about Vitamin K2 and its impact on osteocalcin in metabolic, bone, and cardiovascular health. (1)https://www.sciencedirect.com/science/article/abs/pii/S0899900716000411
The basics about Vitamin MK4 and Vitamin MK7
The research on Vitamin K in its forms of MK4 and MK7 is still evolving and there is still a lot to be learned. What we do know is that Vitamin MK4 (menaquinone-4) and Vitamin MK7 (menaquinone-7) do have important roles supported bone, dental and cardiovascular health (2)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3502319/
How much Vitamin K2 do we need?
Its a little unclear. The NIH guidelines only refer to Vitamin K and don’t break out their guidelines to Vitamin K1 and Vitamin K2.
In fact, until about 2005 or 2006, we really didn’t differentiate between Vitamin K1 and K2 and simply referred to all these chemicals as “Vitamin K.”
The NIH guidelines say that adult men have the highest recommend amounts of Vitamin K, followed by adult women. Surprisingly, the NIH doesn’t make a different daily recommended dose for pregnant women.
|Age and Sex||Daily amounts of Vit K (mcg)|
|Birth to 6 months||2 mcg|
|7 to 12 months||2.5 mcg|
|1 to 3 years||30 mcg|
|4 to 8 years||55 mcg|
|9 to 13 years||60 mcg|
|14 to 18 years||75 mcg|
|Adult Men||120 mcg|
|Adult Women||90 mcg|
|Pregnant and breastfeeding teens||75 mcg|
|Pregnant and breastfeeding adult women||90 mcg|
What are the best foods for Vitamin K2 – MK4?
The best sources for MK4 are from animals or dairy products. So look for grass-fed butter, cheese, eggs from pastured-raised chickens and organ meats like liver and kidneys.
The human body seems to prefer MK4 over MK7 for update in the tissues, while bone seems to uptake MK7 over MK4.
MK4 also seems to be the only form of Vitamin K2 that has a measurable impact on gene expression. (3)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6116188/
It also seems that our bodies will convert other forms of Vitamin K, (including Vitamin K1) to MK4 so it your diet is high in MK7 or Vitamin K1, you might be converting some to MK4. This conversion to MK4 is probably more important for strict vegans that wouldn’t be eating any animal products.
In general, hard cheeses appear to have higher concentration of MK4 than soft cheeses (4)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5946231/ although the Vitamin K2 MK4 concentration appears to also depend on where the cheese is from, how long it is aged as well as fat content.
Other sources high in MK4 include the dark meat of chicken and eel as well as goose liver.
Where are the best foods for Vitamin K2 – MK7?
Fermented foods like Natto (a Japanese dish made from fermented soybeans), kimchi (a Korean dish from fermented cabbage) and sauerkraut all are great sources of Vitamin K – mk7. But having tried Natto several times, I can forewarn you that it takes some time to get used to the “slimy” texture and pungent odor. I tend to go with either fermented sauerkraut or kimchi. Its important to know that the source of the Vitamin K2 is from the bacteria that causes the fermentation and not the soybeans or cabbage, so you won’t get the same benefits of Vitamin K – MK7 from eating edaname or adding shredded cabbage to a salad.
It seems that you don’t need to eat natto every day (whew!) to see an increase in MK-7 levels. A research study published in the Journal of Bone and Mineral Metabolism in 2000 found that eating natto just several times a week increased circulating MK-7 levels significantly higher than those test subjects that either ate natto infrequently (a couple of times a month) or not at all. (5)https://pubmed.ncbi.nlm.nih.gov/10874601/
Vitamin K2 supplements
For some people, taking a Vitamin K2 supplement may also be another way of ensuring that you are getting an adequate amount of Vitamin K2. Since Vitamin K2 works closely with Vitamin D, calcium and magnesium, I currently take a combined Vitamin D3 and Vitamin K2 supplement as well as daily magnesium.
Since Vitamin K2 and Vitamin D are fat-soluble molecules, its also important to take them with a meal that has some fat in it. I usually take my in the morning with the morning coffee that has either grass-fed butter and MCT oil in it.