While vitamins A to E may be common names in your natural health medicine cabinet, vitamin K2 might not sound all that familiar. But stick with us. That’s all about to change!

Vitamin K2, belongs to the vitamin K family and just like vitamin D3, is also a fat-soluble vitamin. There’s a whole family of vitamin K molecules, you say? Yes!

Enter vitamin K1 and K2 (and there are more family members, but these are the two most often found in the human diet and to date have the most impact in the human body). While they each belong to the same fat-soluble family and have similar chemical structures, they each cover their own important functions in the body.

What’s the difference between vitamin K1 and K2?

We often associate the whole vitamin K family with blood clotting. That actually dates back to the accidental discovery of vitamin K, when a Danish scientist found that chickens fed a very low-fat diet bled very easily. This led to the discovery and naming of vitamin ‘koagulation’ or vitamin K for short!

For quite some time after that, the thought was that all forms of vitamin K had the same purpose—to help our blood clot appropriately to prevent excessive bleeding. But today we know that the different forms of vitamin K, mainly vitamin K1 and K2, have different roles in the body. Vitamin K1 mainly influences blood clotting. Vitamin K2 also plays a role in clotting (smaller than K1) but has many other important functions.

Vitamin K1 (also called phylloquinone), is mainly found in green leafy vegetables and is the main form of vitamin K found in the human diet. 90% of all the vitamin K we get from our diet is vitamin K1.

Foods that are rich in Vitamin K1 and K2

Vitamin K2 (also called menaquinone) varies by food source but is most commonly found in fermented foods and animal products that are rich in fat, including butter, dairy and organ meats. Actually, the food containing the highest amount of vitamin K2 is called natto—a Japanese dish made from fermented soybeans. Most typical North American diets don’t include natto, so incorporating cheeses like gouda or brie, animal livers, egg yolks, and fish eggs are good ways to increase your vitamin K2 your diet.

But thanks to refrigeration and canning, we are eating less vitamin K2-rich fermented foods like cured fish and aged cheeses these days, making supplementation important. Besides commonly low food intake of vitamin K2, certain health conditions and medications make you more likely to be low in this vitamin—these include bone conditions like osteoporosis, digestive health concerns like Crohn’s or colitis, and medications like statins.

So what special role does vitamin K2 have in the body?

Vitamin K2 hit the spotlight when research came out looking at calcium supplementation and osteoporosis. Many people who were taking calcium supplements had calcium build up in their arteries and kidneys (not where you want your calcium), and this placed them at risk for heart attacks and kidney stones. It seemed like the body was absorbing the calcium from the supplements, but the calcium was not going to the bones where it was needed.

So what was missing? We’ve since learned that vitamin K2’s job is to help direct calcium into the bones and teeth and away from the other areas of your body, especially your arteries and soft tissue. It does this by activating proteins in the body that regulate calcium integration into bone, and away from the bloodstream.

Who should take vitamin K2?

Most people can benefit from vitamin K2 supplementation!

Children & Teens

Children need nutrients for their rapidly growing bones and skeleton. Bone development begins as early as 6 weeks after conception and continues well into adulthood. Peak bone mass (bone mineral density) is achieved around the age of 20 before beginning a natural and steady decline.

Vitamin K2 is important for incorporating calcium properly into quickly developing bone structure. Together with vitamin D3, these fat-soluble nutrients help to mineralize bones and keep them healthy and strong. Studies have shown that taking vitamin K during childhood years can have a significant impact on bone mineral density.

Pregnant & Menopausal Women

Pregnant women can become calcium deficient because of the increased demand for nutrients to prepare for birth and the baby’s high demand for skeletal formation. In extreme cases, this can result in pregnancy-associated osteoporosis. Vitamin K2 supplementation has been shown to relieve this pain and improve bone health in expectant mothers.

Women nearing menopause also require vitamin K2 and D3, as a decrease in estrogen decreases bone density.

What other health concerns does vitamin K2 target in adults?

Bone Health

Vitamin K2 improves the mineral density and metabolism in adult bones too! It does this by turning on a protein (called osteocalcin) that helps the bone take in calcium and form stronger collagen bonds. This process helps to prevent fractures too! In fact, science has shown that you are more likely to suffer from bone fractures when you have low vitamin K2 intake.

Individuals at risk for osteoporosis or osteopenia and those who are currently taking calcium-containing supplements (i.e., most multivitamins and prenatal vitamins) would all benefit from a vitamin K2 supplement to direct calcium to bones and not to other tissues in the body.

Dental Health

Like our bones, our teeth need vitamin K2 to support mineralization and prevent tooth decay.

Did you know that some of the highest amounts of vitamin K2 in the body are found in our saliva? It seems vitamin K2 has bacteria-fighting effects and reduces the number of cavity-causing bacteria, which helps to prevent tooth decay.

Vitamin K1 and K2 are important for different parts of our body

Heart Health

Vitamin K2 activates a special protein in the blood called matrix Gla protein (MGP). This protein blocks calcium from depositing in your arteries and other soft tissues. Calcium build-up in the arteries reduces the elasticity of your blood vessels—this is known as ‘arterial stiffness.’ Think of a garden hose that becomes really stiff with calcium build-up and water can’t properly flow through—not ideal for your heart vessels. Without this special protein (which is activated by vitamin K2), calcium plaques can also start to build-up in the arteries, which restricts blood flow even more. Calcium deposits in the vessels leading into and out of the heart is a risk factor for heart disease.

Are all vitamin K2s the same?

The simple answer is ‘not quite.’ It turns out that vitamin K2 is actually not a single molecule. It’s actually a collection of molecules called menaquinones (MK), and different forms of these exist. For short, we call these subtypes ‘MK.’ You might notice MK-4 or MK-7 vitamin K2 supplements down the vitamin supplement aisle.

MK-4 versus MK-7

MK-4 has a much shorter lifespan (called a half-life) in the body than MK-7—it actually passes through your body in a matter of hours. MK-7, on the other-hand, has a longer chemical structure and a longer lifespan of about three days.

Because of its longer life in the body, scientists believe MK-7 can reach more parts of the body than the MK-4 form. Scientific studies have shown that the MK-7 form can improve measures of heart health.

The take-home message on vitamin K2

Vitamin K2 does the body good! Most of us get enough vitamin K1 in our diets to keep our blood clotting function under control, but K2 is often lacking in our diets, and has a very important and unique role for your bone and heart health. Vitamin K2 (MK-7 form) has been well-researched and found to improve bone mineral density and heart health, and protect against heart disease.  Vitamin D3 makes a perfect partner, as it helps you absorb dietary calcium and vitamin K2 puts that calcium into the right places.

Check your supplements to see if they contain the right form of vitamin K2 and if not, pick one up and add it to your daily supplement regimen for added bone and heart health protection.

Orange Naturals Vitamin D3 and K2 (MK-7) provides an excellent source of these vitamins. It comes in a base of medium chain triglyceride oil (MCT oil) that allows for superior absorption in a liquid dropper or an organic coconut oil-based soft gel form which is easy for adults and children to ingest.

Read the full K2 primer (which covers why it’s important, how it works, and how it can help your body), by downloading it here.

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