Introduction

Some vitamins, such as Vitamin C and Vitamin D, receive greater recognition than others. Which is perhaps why so many people have never even heard of Vitamin K. In fact, not many multivitamins even include Vitamin K (though there is a reason for that, as we’ll discuss below).

Fortunately, Vitamin K can be found in many types of food. This is why Vitamin K deficiency is rare, according to the U.S. Department of Health and Services. Still, there are many people who could benefit from getting more Vitamin K into their day — and some people who need to avoid it.

Although Vitamin K normally takes a backseat to more prominent vitamins, it is needed to carry out multiple key functions throughout your body. Among these functions are blood clotting and bone mineralization. As a result, this particular vitamin is a vital component in heart health, bone strength, and more.

The Blood Clotting Vitamin

While Vitamin K doesn’t generate the same buzz as other vitamins and minerals, it still serves an important purpose for your health. Vitamin K is known as the “Blood Clotting Vitamin,” and for good reason. In fact, the “K” stands for “Koagulation, the Danish word for “Coagulation.” That’s because an essential cofactor in several Vitamin K proteins are associated with blood coagulation, bone metabolism, and the prevention of mineralization in your blood vessels. According to the U.S. Department of Health And Services, Vitamin K functions as a coenzyme for carboxylase, an enzyme dependent on Vitamin K that is required to synthesize the proteins involved in blood clotting and the formulation of bone marrow.

Two such proteins involved in this process are Prothrombin and Osteocalcin. Both proteins depend on Vitamin K to carry out vital actions — Prothrombin for blood clotting and Osteocalcin for healthy bone marrow production, according to Harvard Health.

Vitamin K for Heart Health

One of the important aspects of how Vitamin K works — especially Vitamin K2 — is how it helps your body process calcium. This is especially critical for the health of your arteries. Calcium often gets “lost” on the way to your bones and can end up “hanging out” in your arteries, affecting arterial integrity, elasticity, and blood flow. However, as a recent study has shown, Vitamin K acts as a “traffic officer,” helping calcium find its way out of your arteries and to your bones.

A review of relevant clinical studied published in the health journal Current Nutrition Reports examined the role of Vitamin K in cardiovascular health. The report indicated that Vitamin K has a potential role in cardiovascular health, but more study should be pursued to discover the full depth of the benefits.

The key takeaway is that Vitamin K has been shown to play a large role in heart health via its support for blood clotting and helping manage calcium mineralization in blood vessels. Hence, the foundation for the correlation between Vitamin K and heart health is clearly laid out, especially when you couple this with Vitamin K’s benefits for arterial health.

Where to Find Vitamin K

Vitamin K is found in traditional sources of food including green leafy vegetables such as spinach, broccoli, Brussels sprouts, kale, and several types of lettuce. Small amounts of this vitamin are found in meat, cheese, and eggs, but you’ll get most of your Vitamin K fix through the aforementioned vegetables.

Here is a list of multiple common – and not so common – food sources of Vitamin K, courtesy of MedlinePlus.

Kale
Cauliflower
Parsley
Collard Greens
Green Leaf Lettuce
Spinach
Broccoli
Brussels Sprouts
Eggs
Pork Chops

Vitamin K can also be found in fermented foods — though the American diet does not contain enough of these types of foods to be considered a significant source.

And while Vitamin K deficiency is currently rare in the U.S., it is a possibility. Medical News Today, a popular health news media outlet that utilizes peer-reviewed studies in their research, acknowledged that certain medical conditions (such as celiac disease or intestinal disorders) and medications (including regular antibiotic use) could reduce Vitamin K production and reduce absorption in the body. As a result, adults may become deficient in Vitamin K. You should always check with your doctor if you have a medical condition or are taking prescription medications about supplementing with Vitamin K or any other supplement.

Types of Vitamin K

There are two primary forms of Vitamin K: Vitamin K1 (phylloquinone), and Vitamin K2 (menaquinone). Although each form is found in different sources of food, Vitamin K1 is considered the primary form of this particular vitamin. Vitamin K1 is found in green leafy vegetables such as spinach, kale, and broccoli, while K2 is present in meat, dairy, and eggs.

Aside from the food sources where each form can be found, the main difference between Vitamin K1 and K2 is absorption. According to Healthline, Vitamin K1 found in plants is poorly absorbed by the human body. One study, titled “Effect of Food Composition on Vitamin K Absorption in Human Volunteers,” found that less than 10% of Vitamin K1 found in plants is absorbed.

Although less concrete evidence doesn’t help the case for Vitamin K2 when it comes to absorption, it is believed that this form is better absorbed by the human body than its counterpart. However, a 2013 study concerning the role of Vitamin K2 cited “significant gaps” in current knowledge of this form of Vitamin K, but acknowledged the differing chemical structures between the two forms. Hence, the different chemical structures affect bioavailability and metabolism in the body.

With this in mind, it is also important to consider the fact that Vitamin K is one of four fat-soluble vitamins in the human diet. Vitamin K — along with Vitamin A, D, and E — are better absorbed into your bloodstream when consumed with fat. This helps the case for Vitamin K2 and its ability to be absorbed better than K1 because it is found in animal food sources such as meat, dairy, and eggs. Since these foods contain more fat than leafy green vegetables, it is likely that Vitamin K2 is more bioavailable and better absorbed than Vitamin K1.

Be on The Lookout for Future Studies!

As mentioned, Vitamin K is directly involved in blood clotting and the prevention of mineralization in blood vessels. As a result, there is a growing belief that Vitamin K is beneficial for cardiovascular health, especially as concerns the flexibility and elasticity of our arteries — the “superhighway” for blood flow. This is why it is important to stay on top of the latest clinical studies that concern Vitamin K and its role in heart health, bioavailability, and more!

A Warning About Vitamin K Supplementation

While many people might benefit from getting a daily dose of Vitamin K in their diet through supplementation, there are other people who should avoid Vitamin K — or at least speak with their doctor first. That is due to Vitamin K’s coagulation/blood clotting action. People who are prescribed blood thinners should avoid Vitamin K — which would work against the action of their medication. This is why most multivitamins leave Vitamin K out of the mix. However, it has also led to Vitamin K getting a bad reputation, especially among people concerned about heart health. It is important to educate yourself about Vitamin K — and to speak with your doctor if you are on anti-coagulants to find alternate ways to support healthy blood flow and arterial integrity.

References

https://www.healthline.com/nutrition/fat-soluble-vitamins#vitK

https://www.healthline.com/nutrition/vitamin-k1-vs-k2 - TOC_TITLE_HDR_3

https://www.hsph.harvard.edu/nutritionsource/vitamin-k/

https://www.medicalnewstoday.com/articles/320394#causes

https://medlineplus.gov/ency/article/002407.htm

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5585988/

https://ods.od.nih.gov/factsheets/VitaminK-Consumer/

https://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/

https://pubmed.ncbi.nlm.nih.gov/23590754/

https://pubmed.ncbi.nlm.nih.gov/8813897/

https://www.mdpi.com/2072-6643/7/11/5443/htm