The Health Benefits of Vitamin K2

Vitamin K2 May Offer Benefits Related to Heart Disease, Cancer, and Bone Health


Verywell / Alexandra Shytsman

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Vitamin K2 is a member of the vitamin K family, a class of nutrients involved in blood clotting and maintaining bone health. Found naturally in some animal-based and fermented foods, vitamin K2 is also synthesized by gut bacteria.

Vitamin K2 supplements are sometimes referred to as menaquinone. The most studied forms of menaquinone include MK-4 (menaquinone-4), MK-7 (menaquinone-7), and MK-9 (menaquinone-9).

Vitamin K1—also known as phylloquinone or phytonadione—is another common form of vitamin K.

Health Benefits

Studies have connected vitamin K2 with certain health benefits. The National Institutes of Health recognizes two: those related to osteoporosis and those related to coronary heart disease. Additional research recognizes a few others.

Greater Bone Health

From birth through childhood, our bones grow and develop. This is referred to as bone modeling. Once they've matured, bones transition from modeling to remodeling. Bone remodeling helps the skeletal system maintain its structure and strength as we age.

Osteoporosis is the most common bone remodeling disease, resulting in reduced bone mass and greater bone fragility. Yet, several studies have found that vitamin K2 may help improve bone health, reducing these effects.

For instance, one study looked at 19 different controlled trials and concluded that vitamin K2 can help reduce the risk of fractures for women who are post-menopause. This may be, in part, because it helps increase bone flexibility.

Reduced Heart Disease Risk

Some studies suggest that vitamin K2 might reduce your risk of heart disease. One piece of research explains that it does this by activating proteins that inhibit calcium deposits on blood vessel walls, thereby reducing vascular damage.

This research further suggests that taking vitamin K2 can also reduce risks associated with taking higher amounts of calcium. Namely, it helps inhibit calcification and stiffening of the arteries, reducing calcium buildup in blood vessels and soft tissues.

Another study found that daily K2 supplementation helps decrease vascular calcification in patients with kidney disease who are being treated with hemodialysis. This study involved the use of MK-7, specifically.

Lower Diabetes Risk

A 2018 review reports that supplementing with vitamin K2 appears to reduce the risk of developing type 2 diabetes, even more so than vitamin K1. It does this by increasing insulin sensitivity, promoting bone hormone metabolism, and acting as an anti-inflammatory.

Other studies suggest that vitamin K2 is beneficial for people with type 2 diabetes in the way it interacts with certain bacteria in the gut. While it doesn't necessarily make the gut microbiome healthier, it does appear to improve metabolic capability when low-grade inflammation exists.

Aids in Cancer Treatment

Preliminary research indicates that vitamin K2 may aid in the treatment of some forms of cancer. For example, in a report published in European Journal of Surgical Oncology, researchers found that vitamin K2 significantly improved one-year survival in people with hepatocellular carcinoma.

Conversely, a study published in Clinical Nutrition in 2017 found that vitamin K intake was not associated with cancer mortality. So, research in this area is somewhat mixed, making it a bit more inconclusive.

Possible Side Effects

The National Institutes of Health reports that, while vitamin K has no known adverse effects and a low risk of becoming toxic when taken in higher doses, it can potentially interact with a variety of prescription medications, including:

  • Anticoagulants, such as warfarin (Coumadin) and phenprocoumon
  • Antibiotics, primarily cephalosporin antibiotics like cefoperazone (Cefobid)
  • Bile acid sequestrants, such as cholestyramine (Questran) and colestipol (Colestid)
  • Orlistat, a weight loss drug found in Alli (over the counter) and Xenical (prescription) medications

Before you begin using vitamin K2, talk to your doctor to determine if it is safe given your current health and medication usage.

Dosage and Preparation

The Office of Dietary Supplements shares that adult men should consume 120 mcg of vitamin K daily, with adult women needing slightly less, or 90 mcg per day. However, some researchers are asking that recommendations be made for vitamin K2 specifically.

If you want to increase your vitamin K intake by taking a supplement, most multivitamins contain up to 75% of the recommended amount. You can also purchase a standalone K supplement or a combination supplement (such as a vitamin D and K combination).

Speak to your doctor before taking a vitamin K supplement above the recommended amount.

What to Look For

To boost your intake of vitamin K2 specifically, it's important to read the supplement's label. Look for MK-4 or MK-7. Research has found that MK-7 has a longer half-life and greater bioavailability, making this the preferred type if you can find it.

One study reports that diet alone typically supplies up to 25% of daily vitamin K2 intake, with this nutrient found in foods such as cheese and natto. You can also increase K2 in your diet by eating more collards, turnip greens, spinach, and kale.

Other Questions

Still have questions about vitamin K2? Here are a couple of the most common, as well as their answers:

Who Is at Risk of a Vitamin K2 Deficiency?

While deficiency is rare in the U.S., people who have had bariatric surgery or a medical condition that impacts vitamin K absorption ( such as celiac disease) may find it difficult to get adequate amounts of this nutrient.

What Happens If I Am Deficient in Vitamin K2?

If you don't have enough vitamin K, you may have an increased risk of excessive bleeding and an increased risk of bone fractures and bone diseases such as osteoporosis.

If you are concerned that you may be deficient in vitamin K2, talk to your doctor to determine whether your levels should be tested.

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