Many people know that vitamin K1 is involved in helping blood clot. It’s found in plant foods, particularly leafy greens. Examples include kale, collard greens, spinach, turnip greens, broccoli, and Brussels sprouts.
Apparently, vitamin K1 deficiency is rare.
But another vitamin – K2 – is important for its completely different functions. K2 helps to:
• prevent cardiovascular disease
• form strong bones and teeth
• prevent osteoporosis
• prevent kidney stones
• promote healthy skin and prevent wrinkles
• prevent cavities, and more.
K2 is found primarily in animal products and fermented foods. (It has several subtypes, but I’m going to declare that info beyond the scope of this brief article!) Food sources of K2 are listed below.
While K1 and K2 are similar in structure, they seem so different. Is there any connection between the two? And if so, what is it?
Let’s Start with How K2 Prevents Cardiovascular Disease
K2 promotes the deposit of calcium in bones and teeth, especially when it’s combined with vitamin D3. That’s because K2 activates osteocalcin and other proteins related to skeletal growth and bone formation.
Yet K2 also prevents the deposit of calcium in soft tissues, where it doesn’t belong. As a result, it can help prevent calcification of arteries and the formation of atherosclerotic plaques.
That’s its link with cardiovascular disease prevention.
Why Are Animal Products the Primary K2 Source?
The human body can convert K1 to K2 but is limited in its ability to do that. Animals are better at the conversion process.
And here we find the connection between the 2 vitamins.
Animals get their K1 from eating grasses and other plants. They convert that K1 to K2.
So it’s not enough to eat cheese or butter to get K2, for example – even though some sources simply list those foods. Instead, we need to choose cheese or butter from grass-fed cows because of the K1/K2 connection.
Fermented cheeses – such as Jarlsberg, Edam, Gouda, cheddar, Brie, and blue – contain vitamin K2 formed by the bacteria used during their production. Of these, cheddar and Brie are particularly high in K2 due to the types of bacteria used.
Ghee (clarified butter) from grass-fed cows is an excellent source of K2, even better than regular butter.
Egg yolks are another good source of K2 – but should come from free-range chickens, which eat grasses.
Dark chicken meat and beef are good K2 sources, but again should be from grass-fed animals.
Two other sources are goose liver and chicken liver. In keeping with the other K2 info, my recommendation would be to eat free-range versions of those animal products, as well.
What Should Vegans Eat to Get K2?
Natto from fermented soy is one of the few non-animal sources of vitamin K2, and has a high K2 content.
Sauerkraut is another K2 source.
I suggest real, fermented sauerkraut. That means the label should list only 2 ingredients: cabbage and salt. Possibly water, as well. Avoid a more “standard” product with vinegar. That would actually be pickled cabbage, not fermented sauerkraut.
Kimchi is fermented vegetables and also contains K2.
So there’s a little info on vitamin K2. Because we can convert K1 to K2 to some degree, I’d recommend that you eat plenty of leafy green vegetables – for many health reasons, but also to get lots of K1.