Vitamin K is best known for its role in blood clotting. This is actually how it was named, the K stands for the Danish word “koagulation”. However, there’s more to vitamin K than just blood clotting. 

We’re taking a look at what vitamin K has to do with your cardiovascular health, including how much you need and high vitamin K foods to include in your diet.

What is Vitamin K?

You may be surprised to learn that vitamin K isn’t just one nutrient, but the name for a group of nutrients that share a common chemical structure. Getting enough vitamin K is important for functions like proper blood clotting, supporting strong bones, and cardiovascular wellness.

The two main types of vitamin K include: 

• Vitamin K1 (Phylloquinone): The primary job of Vitamin K1 is to allow for normal blood clotting. It’s involved in the production of clotting factors, which are needed to heal wounds and prevent excessive bleeding.
• Vitamin K2 (Menaquinones): Vitamin K2 is involved in calcium metabolism. It helps shuttle calcium into your bones and teeth, supporting bone health and reducing your risk of osteoporosis. It also helps keep calcium from being deposited in your arteries. This potentially reduces the risk of arterial calcification (when calcium deposits abnormally build up in your arteries and raise your risk of having a heart attack).

And for an important distinction: is vitamin K potassium? No, vitamin K and potassium aren’t the same nutrients. They are commonly mistaken as such because the chemical symbol for potassium is K. 

Vitamin K and Cardiovascular Health

Getting enough vitamin K in your diet is important for overall health. The different types of vitamin K have unique roles in supporting the health of your heart but it’s important to get a combination of both.

Vitamin K and arterial calcification

Arterial calcification is a hallmark of atherosclerosis and a major risk factor for cardiovascular disease and stroke. Vitamin K2 plays a crucial role in preventing this calcification, by activating a protein called Matrix Gla Protein (MGP). 

Maintaining levels of vitamin K may help support calcium regulation, keep your arteries flexible, and lower the risk of cardiovascular problems associated with calcification.

Vitamin K on vascular health 

The role of vitamin K2 in regulating calcium metabolism and preventing arterial calcification is important for vascular health as it helps protect your arteries. While vitamin K1 isn’t directly linked to heart health, its role in blood clotting indirectly affects cardiovascular wellness. 

For instance, proper blood clotting prevents excessive bleeding during injuries and surgeries. Excessive clotting can lead to issues like thrombosis, which is a risk factor for heart attacks and strokes. Therefore, striking a healthy balance between too much and too little vitamin K is critical for a healthy heart.

Vitamin K2 and Vitamin D

You may have seen supplements with both vitamin K2 and vitamin D. This is because they work together to support:

• Bone health: Vitamin D helps increase calcium absorption, while vitamin K2 ensures that the absorbed calcium is properly used and directed to the bones. This helps prevent accumulation in arteries or other soft tissues. 
• Cardiovascular health: Vitamin D may indirectly support heart health by promoting proper calcium metabolism. As previously mentioned, Vitamin K2 directly prevents arterial calcification, thus complementing each other’s roles in maintaining a healthy cardiovascular system.

If you don’t eat enough dietary sources of vitamin D and vitamin K2, it may be worth a conversation with your healthcare provider or registered dietitian who specializes in heart health to see if it makes sense for you to supplement.

Vitamin K Deficiency and Cardiovascular Risks

Vitamin K deficiency affects an estimated 8% to 31% of healthy adults at any time. However, most people don’t experience noticeable symptoms (like significant bleeding or slowed clotting times), so it may not be quickly diagnosed. Clinically severe vitamin K deficiency in adults is fairly rare. 

The daily amount of vitamin K determined to be enough for general health is 120 mcg for adult men and 90 mcg for adult women, including during pregnancy and lactation. 

Most newborns receive a vitamin K injection at birth. Newborns who don’t receive this standard injection at birth are at the highest risk of developing vitamin K deficiency. People who have malabsorptive disorders like cystic fibrosis, Celiac disease, ulcerative colitis, and short bowel syndrome are also at risk. 

Vitamin K deficiency may increase your risk of cardiovascular disease because of how it affects calcium regulation and arterial calcification, though more research is needed.

Vitamin K and Medication Interactions

People who take certain medications that may interfere with vitamin K absorption or activity may be at a higher risk of deficiency over time, such as: 

• Bile acid sequestrants: used to lower cholesterol levels by preventing the reabsorption of bile acids.
• Some antibiotics: may destroy vitamin K-producing bacteria in the gut.
• Weight loss medications like Orlistat: may reduce how much dietary fat and fat-soluble vitamins your body can absorb.
• Blood-thinning medications (anticoagulants) like Warfarin (Coumadin): work against the activity of vitamin K and lower your levels. 

If you’re taking any of the medications above, especially when it comes to vitamin K and warfarin, work with a registered dietitian who specializes in heart disease to ensure your vitamin K intake is consistent. Dramatically changing how much vitamin K you’re consuming can interfere with how well your blood thinner works and influence your vitamin K levels. It’s better to find consistency versus not eating vitamin K foods.

Practitioners use a tool called international normalized ratio (INR) when someone is using an anticoagulant or other medication with a higher risk of interacting with vitamin K. INR helps assess the risk of excessive bleeding and is monitored while you’re using these medications. INR values help practitioners determine whether an adjustment is needed in your medication, diet, or both. 

High Vitamin K Foods

It can be tempting to seek out vitamin K supplements when you’re trying to increase your intake. However, it’s almost always better to emphasize getting nutrition from whole and minimally processed foods. Typically supplements should be reserved for specific circumstances or when they may be prescribed to correct a deficiency. 

Most cases of vitamin K toxicity are associated with taking too many supplements. Taking high-dose single-nutrient supplements increases your risk of getting too much, exceeding the tolerable upper level, and experiencing related adverse outcomes.  

Vitamin K toxicity from dietary sources is rare because your body regulates its absorption and excretion efficiently. Focus on getting the high vitamin K foods below, rather than taking a supplement. 

Vitamin K1 foods

Some of the best sources of vitamin K1 foods are green and cruciferous vegetables. Green leafy vegetables such as spinach, kale, Brussels sprouts, collard greens, Swiss chard, and lettuce are great choices. Kiwi fruit and parsley are also rich vitamin K1 foods.

Vitamin K2 foods

Vitamin K2 can be found in certain animal-derived foods like aged Gouda and Brie cheese, pasture-raised eggs, and beef. It can also be found in fermented foods like natto (a traditional Japanese dish made from fermented soybeans) and sauerkraut. 

Vitamin K: The Takeaway

Vitamin K is important for supporting healthy bones and cardiovascular health and it’s best to get it from food sources. You can get a mixture of vitamin K1 and K2 by eating a variety of leafy greens, cruciferous vegetables, specific fermented foods, kiwi, and eggs. 

If you’re interested in optimizing your heart health through science based nutrition, join my 6 week heart optimization group program. For more individualized guidance for optimizing your diet for heart health, learn more about 1:1 counseling sessions with me here. 

References

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