Vitamin K2: Vital for Calcium Absorption & More


By Lee Cowan

We’ve all seen the ubiquitous use of vitamin D as a supplement in milk, aiding in the absorption of calcium. We know how important calcium is for good bone health. But how many of us are aware that it is vitamin K2 that ensures that the calcium we are so careful to consume is actually binding to bones and teeth, instead of calcifying in the arteries, causing hardening and blockages?

“Scientific studies confirm that increased dietary intake of vitamin K2 does indeed reduce your risk for coronary heart disease,”says Dr. Joseph Mercola.  Vitamin K2 directs calcium away from the arterial walls, thus keeping your coronary arteries clear of calcium deposits that lead to the hardening of arteries and often to heart attacks. Consuming the wrong kind of calcium or having it deposited in the wrong places in our bodies because of vitamin K2 deficiency can lead to a whole host of other medical conditions, including:

  • Gallstones, colon cancer, and Crohn’s disease
  • Coronary artery disease and atherosclerosis
  • Kidney stones
  • Dental plaque and gum disease
  • Ovarian cysts
  • Hypothyroidism
  • Cataracts, glaucoma, and macular degeneration
  • Obesity and diabetes
  • Bone spurs, stiff joints, osteoarthritis, tendonitis, and bone cancer
  • Alzheimer’s disease
  • Cellulite and scar tissue
  • Breast cancer and cysts (fibrocystic breasts)

Clearly, vitamin K plays an important role in the long-term health of our bodies. But getting enough vitamin K is a little bit complicated. There are different forms of vitamin K and one of them has several different sub-types.  So taking a vitamin K supplement does not ensure you are getting the type of vitamin K that works with calcium and vitamin D.

Here’s a little history. Researchers have been studying vitamin K since Dr. Weston A. Price identified what he called “Activator X” in 1945, noting that it was an essential activation agent in the appropriate absorption and distribution of other nutrients, specifically calcium, vitamin D and vitamin A. He didn’t recognize this “X factor” as vitamin K.  And even though scientists knew about vitamin K, they thought the two forms of it did the same thing. It wasn’t until 1997 that researchers discovered that vitamin K2 had a distinct and important job.  And finally in 2007, Dr. Price’s “activator X” was linked with vitamin K2.

Picture of a bottle of Just Thrive Vitamin K2-7 in front of a pile of chickpeas.Vitamin K1 (phylloquinone) is found in plants, especially dark leafy greens, and is used primarily to help clot the blood. It is vitamin K2 (menaquinone) that the body uses preferentially to deposit calcium in the teeth and bones. It is essential to help maintain bone strength.(1) Some studies suggest that one form of K2 (menaquinone-7, also known as MK-7), which is derived from fermented food products like certain cheeses and a fermented soy-based food called natto, is more bioavailable than menaquinone-4 (MK-4), found in grass-fed animal products.(2) Many of these studies were performed on vitamin K2 supplements, so if you’re looking for supplements, one excellent product for this MK-7 form of K2 is Just Thrive K2-7.

Sometimes supplements are necessary, either for convenience or to get higher doses more frequently, or because our food is not as rich in vitamins and minerals as it once was.  However, whole food sources of nutrients are always the first place I look to find the extra nutrition I need.  There are certain nutrient dense foods, or “superfoods,” that are so rich in nutrition that they are almost like taking a vitamin supplement.  But humans have been using many of these foods since before modern technology knew anything of vitamins, minerals, or gel caps.  

Walkabout_Emu_OilOne of these superfoods is emu oil. Considered a sacred food among Australian Aboriginals, studies at the Weston Price Foundation have found that it is the highest whole food source of vitamin K2. However, not all emu oil is created equal. The emu oil with the most bioavailable form of vitamin K2 comes from a specific genotype of emu found only in Australia and only in populations that are 100% grass-fed and never given antibiotics or GMOs. Walkabout Emu Oil meets all these criteria.

The second highest source of K2 is Green Pastures Butter Oil.  Only animals fed their natural food source, grass, and able to move freely in the sunlight are able to make vitamin K through bacterial processes in their gut. So factory farmed animals, fed a diet of GMO grains and confined in industrial warehouses are not a significant source of vitamin K2.Picture of a cow eating nice green grass next to a bottle of Green Pasture X-Factor Gold High Vitamin Butter Oil.

So who needs extra vitamin K? Our bodies produce vitamin K in the intestines, so we should be all set, right? It turns out that only K1 is recycled in the intestines, while K2 is available only through food sources. And even though a healthy gut does produce proper amounts of vitamin K1 and grass-fed animals should be a good source of vitamin K2, there are several conditions and medications that can cause a deficiency.  Also, because of the use of chlorinated water, antibiotics, alcohol, and the depletion of our soil, our intestines are no longer the vibrant garden of trillions of microorganisms that they once were.

Certain health conditions contribute to a vitamin K deficiency, including:

  • Gallbladder or biliary disease
  • Cystic fibrosis
  • Celiac disease
  • Crohn’s disease
  • Liver disease

Other medical interventions that can lead to a vitamin K deficiency are the use of blood thinners such as warfarin (Coumadin), long-term hemodialysis, and prolonged or frequent use of antibiotics.  Because antibiotics kill the beneficial flora and fauna of the digestive tract, it hinders the body’s ability to produce vitamin K.(3)

Researchers recommend a range of dosing for vitamin K between 45 mcg and 185 mcg daily for adults. And if you are taking an oral vitamin D supplement you must also consume vitamin K2 in food or supplement form because an imbalance of these two vitamins can actually be harmful.  Even if you do not have any of the diseases or medications mentioned above, research suggests that you could still be vitamin K2 deficient if you do not regularly consume foods that are high in vitamin K2, namely grass-fed animal products, certain fermented foods (like natto or vegetables fermented using vitamin K2-producing bacteria), or cheeses such as Gouda and Brie. It is also recommended that you eat vitamin K2 with fat, since it is fat soluble and cannot be absorbed without it.(4)

So if you are the kind of person who eats only grass-fed animal products and loves their sauerkraut and Brie cheese, and you eat a lot of them every day, you’re getting closer to having enough vitamin K2. Unfortunately, it’s most likely that you still need a supplemental source of vitamin K2.  You would have to eat around 18 egg yolks to get the minimum vitamin K2 requirement or 15 tablespoons of butter (these numbers would vary slightly depending on how much quality grass the animals were eating). And you’d have to eat this much every day. That might be a little much for most of us.(5)

So in light of how important vitamin K2 is and how hard it is to get from food sources, I’m definitely going to start taking a whole foods based supplement. And I look forward to strong teeth and bones and continued health for many long years.


2 thoughts on “Vitamin K2: Vital for Calcium Absorption & More

    • Natto is a great source of vitamin K2-7, as stated in the article, but not so much K2-4. K2-4 comes from animal sources like Walkabout Emu Oil, Green Pasture Concentrated Butter Oil, and salmon. While some people consider natto a superfood, I still can’t help but worry about the hormonal effects of even good, NON-GMO soy. (Soy is a GMO crop so you have to be very careful about the source.) There is evidence supporting both sides of the soy and hormones controversy, so I won’t risk eating it every day. I really like my Emu Oil, and don’t have to worry about hormones or GMOs.

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