Vitamin K2, What You Need to Know

If you are familiar with Vitamin K, you may know about its role in normal blood clotting. You may have learned about Vitamin K when it was suggested for your newborn at birth.

That is Vitamin K1. 

K2 is the little known but other very important form of Vitamin K.

Only very recently has it been understood that there are multiple forms of Vitamin K. Both the scientific community and the general public have been unclear about this.

Previously, it was thought that vitamins K1 and K2 were different forms of the same vitamin, having the same functions in our bodies.

According to more recent evidence, K2’s role extends far beyond blood clotting.

K2 may prevent chronic disease including:

• Preventing heart disease
• Ensuring healthy skin
• Forming strong bones and improving bone health
• Promoting brain function
• Supporting growth and development
• Helping to prevent cancer and kidney stones

K2 has many functions not associated with K1. For this reason many researchers insist K1 and K2 are best seen as two different vitamins.

So what exactly does K2 do that is so important?

K2 helps us put calcium where we need it, like into bones and teeth.

And, maybe even more importantly, it keeps calcium from going where it does not belong, like the soft tissues of your kidneys, heart, brain and the lining of your blood vessels.

Calcium deposited in these soft tissues can result in kidney stones, heart disease, brain malfunction or atherosclerosis, often known as “hardening of the arteries”.

A large study from the Netherlands illustrates the difference between K1 and K2. They measured the extent of heart disease and how this related to K2 intake and blood vessel calcification or hardening.

They found that calcification of the arteries was the best predictor of heart disease. Those with the highest intake of K2 were:

• 52 percent less likely to develop severe calcification of the arteries

• 41 percent less likely to develop heart disease

• 57 percent less likely to die from heart disease

Vitamin K1 intake had no effect on participants’ heart health.

In an acknowledgment of the different roles played by vitamins K1 and K2, the United States Department of Agriculture (USDA) determined Vitamin K2 contents of foods in the U.S. diet for the first time in 2006.

So, how can you get K2 in your diet? You may have to be really intentional about it. You don’t need much, but you do want to make sure you get at least the daily requirement of 90-120 micrograms.

Here is a list of food sources of K2 according to Dr Axe:

The 20 best vitamin K2 foods include (percentages based on daily value requirement of 120 micrograms):

• Natto: 1 ounce: 313 micrograms (261 percent DV)
• Beef liver: 1 slice: 72 micrograms (60 percent DV)
• Chicken, especially dark meat: 3 ounces: 51 mcg (43 percent DV)
• Goose liver pate: 1 tablespoon: 48 micrograms (40 percent DV)
• Hard cheeses such as Gouda, Pecorino Romano, Gruyere, etc.: 1 ounce: 25 micrograms (20 percent DV)
• Jarlsberg cheese: 1 slice: 22 micrograms (19 percent DV)
• Soft cheeses: 1 ounce: 17 mcg (14 percent DV)
• Blue cheese: 1 ounce: 10 micrograms (9 percent DV)
• Ground beef: 3 ounces: 8 micrograms (7 percent DV)
• Goose meat: 1 cup: 7 micrograms (6 percent DV)
• Egg yolk, specifically from grass-fed chickens: 5.8 micrograms (5 percent DV)
• Beef kidneys/organ meat: 3 ounces: 5 mcg (4 percent DV)
• Duck breast: 3 ounces: 4.7 micrograms (4 percent DV)
• Sharp cheddar cheese: 1 ounce: 3.7 micrograms (3 percent DV)
• Chicken liver (raw or pan-fried): 1 ounce: 3.6 micrograms (3 percent DV)
• Whole milk: 1 cup: 3.2 micrograms (3 percent DV)
• Canadian bacon/cured ham: 3 ounces: 3 micrograms (2 percent DV)
• Grass-fed butter: 1 tablespoon: 3 micrograms (2 percent DV)
• Sour cream: 2 tablespoons: 2.7 micrograms (2 percent DV)
• Cream cheese: 2 tablespoons: 2.7 micrograms (2 percent DV)

"Grass-fed” and “pastured-raised” animal foods have more K2 than products that come from factory farm raised animals. This is because the more vitamin K1 an animal consumes in its diet, the higher the level of K2 that will be stored in the tissues.

Natto is a fermented soy food native to Japan. Apparently, it is quite an acquired taste. It is the only plant-based food source of K2 that I know of.

So, if you don’t eat natto, and you don’t regularly eat liver and dairy, you may want to supplement Vitamin K2. 

Lastly, it was once thought that intestinal bacteria played a major role in supplying the body with K2. It now seems this may not be the case. 

Most of the K2 produced in the intestine is embedded in bacterial membranes and not available for absorption. So, intestinal production of K2 likely makes only a small contribution to your vitamin K status.

This is why the recent explosion of attention to Vitamin K2.  Whether from diet or supplement, it is critical for good health.

Work with me to assess your diet and lifestyle for K2 and other health-promoting foods and actions.