· By Kelin Marquet
Vitamin K2 Benefits
Have you heard of vitamin K2? Most people haven't, and many confuse it with vitamin K1. While both fall under the vitamin K family, they function differently in the body and are often discussed separately.
Intake of this important nutrient tends to be low in the typical diet. It’s found mainly in the fatty portions of animal products, especially organ meats, as well as certain fermented foods.
Let’s walk through what vitamin K is, how K1 differs from K2, key vitamin K2 functions, and how to get more of it in your routine.
What Is Vitamin K?
Vitamin K was first described by Nobel Prize–winning scientist Henrik Dam in 1929. He discovered that certain foods, such as green leaves and hog liver, supported healthy blood clotting in chicks experiencing unusual bleeding. After further research, he named this newly identified compound vitamin K for Koagulation, the German spelling.
Around the same time, researcher Weston A. Price traveled the world studying traditional diets and noted that many populations consumed a nutrient he referred to as “activator X.” These groups appeared to have stronger teeth and overall wellness compared with those eating more modern diets. That compound is now understood to be vitamin K2.
There are two main forms of vitamin K:
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Vitamin K1 (phylloquinone) — found in plant foods
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Vitamin K2 (menaquinone) — found in fermented foods and animal products
Within K2, the most common subtypes are MK-4 and MK-7.
Vitamin K1 vs. Vitamin K2
Both K1 and K2 assist with blood clotting. For a long time, scientists thought they played similar roles in the body, but newer research suggests they behave differently in several ways.
Vitamin K2 supports the regulation of calcium in the body. It helps direct calcium away from soft tissues where it is not needed, and toward bones and teeth where it plays a structural role. (3,4)
Some researchers believe K1 and K2 should eventually be categorized as separate nutrients because of these differences.
Studies exploring vitamin K intake for bone and cardiovascular health have found that vitamin K2 supports positive outcomes, whereas K1 did not show the same effects. (5)
In animal studies, K1 also did not support the same calcium-related processes as K2. (6)
Vitamin K2 Benefits
While both K1 and K2 help maintain normal blood clotting, K2 offers additional benefits:
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Supports calcium balance
K2 helps support the breakdown and movement of calcium within the body. This helps maintain flexibility in blood vessels and supports overall circulatory wellness. -
Supports bone strength
By helping activate proteins involved in guiding calcium into bones and teeth, K2 plays a supportive role in maintaining bone density. (8) -
Supports healthy cell function
Research has explored how K2 interacts with cellular processes throughout the body. Findings suggest it plays a role in maintaining normal cell activity, and certain studies have examined its relationship with long-term health outcomes. (9)
What Foods Have K2?
Most people consume significantly more K1 than K2. While some K1 can convert into K2, the process is not very efficient, so getting K2 directly from food is ideal.
K2 can also be produced in the gut, and some studies suggest that broad-spectrum antibiotics may reduce natural K2 levels. (10)
Rich dietary sources of K2 include:
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Animal products
Especially organ meats such as beef liver. Eel, butter, and some cheeses like muenster contain notable amounts. Some egg yolks also contain K2, depending on the hens’ diet. Animal foods tend to be highest in the MK-4 form. -
Fermented foods
Natto (fermented soybeans) is one of the richest sources, with about 150 mcg per teaspoon. Sauerkraut and miso also contain K2.
If your diet does not regularly include these foods, a vitamin K2 supplement can help support adequate intake. Many people choose a combined D3-K2 supplement, such as Why Not Natural D3-K2, because vitamins D3 and K2 work together in complementary ways related to calcium balance.
Disclaimer
The statements in this article have not been evaluated by the Food and Drug Administration. The products mentioned are not intended to diagnose, treat, cure, or prevent any disease. Please check with a doctor before starting any new supplement and to ensure the advice in this article is right for you.
References
(1) https://link.springer.com/chapter/10.1007/978-1-4899-1789-8_19
(2) https://www.westonaprice.org/health-topics/in-defense-of-vitamin-k2-mk-4-dr-prices-activator-x/
(3) Osteocalcin: the vitamin K-dependent Ca2+-binding protein of bone matrix https://pubmed.ncbi.nlm.nih.gov/3530901/
(4) The role of vitamin K in soft-tissue calcification