Vitamin K1 Vs K2: What Are The Differences?

Unlike popular letter vitamins such as vitamin D, C, or B, vitamin K is often left behind. Vitamin K, much like vitamin B, refers to a group of several fat-soluble vitamins, not just a singular vitamin, hence vitamin K1 and vitamin K2. Vitamin K is well-known for its main purported and proven health benefit of its involvement with blood clotting and coagulation. We’re going to talk about vitamin K1 vs K2, their benefits, the differences, and what vitamin K rich foods you’ll want to include in your diet.

What Is Vitamin K 

Vitamin K is an essential bioactive compound which is required for its most researched and proven benefit - blood-clotting. Vitamin K also assists in the process of making various proteins and the building of bones. There are many various forms of vitamin K, however the two most well-known are vitamin K1 phylloquinone (K1) and menaquinones (K2).

Vitamin K1 is namely found in plants and leafy greens such as kale, spinach, and broccoli. Vitamin K2 is mainly found in fermented foods and animal products, such as beef, chicken, pork, cheese, and sauerkraut.  K2 can also be produced by bacteria in the gut.

Vitamin K Benefits

Blood Clotting

Vitamin K’s most well-known benefit is established in its biological role of blood clotting, which helps stop bleeding so that your body can adequately heal. The etiology shows that vitamin K serves as a coenzyme for Carboxylase, the primary enzyme needed for homeostasis, otherwise known as our blood coagulation process. Coagulation is the process of your blood transforming from a free-flowing liquid to a slow-gel like state, to prevent further hemorrhaging. Without an adequate amount of vitamin K in your diet, the risk for anti-coagulation and bleeding.

Heart Health

Cardiovascular disease is the leading cause of mortality in the world. A randomized double-blind controlled trial published in Thrombosis and Homeostasis, reported that 180mcg per day for three years, may inhibit age-related stiffening of the artery walls, and improve vascular elasticity. The results showed a 50% decrease in desphospho-uncarboxylated Matrix Gla-Protein (dp-ucMGP) [R]. Three years may seem like a long time, however foods such as kale, spinach, and collard greens have over 1,000mcg per cup [R]. Therefore, including leafy greens in your diet on a daily or just weekly basis, will assist in positively mitigating age-related cardiovascular events.

A study published in the Journal Of The American Heart Association also found that higher inactive levels of dp-ucMGP, was associated with a range of negative cardiovascular events including arterial stiffness [R].     

Bone Health

Vitamin K benefits bone density, growth, and strength. Your body needs vitamin K to activate proteins necessary for bone growth. It is required for the gamma-carboxylation of osteocalcin (the most abundant noncollagenous protein in bone), making osteocalcin functional. Epidemiologic studies suggest a diet high in vitamin K is associated with a lower risk of hip fractures in aging men and women. Therefore, vitamin K deficiency, may lead to an increased risk of osteoporosis, and a higher risk of bone fractures [R]. Increasing evidence also shows that vitamin K positively affects calcium balance, a key mineral in bone metabolism [R].

RELATED ARTICLE 5 Best Supplements For Bone Health

Vitamin K1 Vs K2: Differences And Similarities

The main benefits and functions of all forms of vitamin K is to activate proteins serving roles in blood clotting, bone health, and heart health.

Although K1 and K2 share similar structures, they do possess fundamental differences regarding absorption, proposed health benefits, and the source in which you derive them. That being said, K2 does have longer side chains, which allows it to circulate in the blood longer than K1. 

Vitamin K2 is found in animal products and fermented foods such as cheese, sauerkraut, chicken, and beef, as opposed to vitamin K1 which is primarily found in plant sources such as leafy greens. The main source of K2 is also synthesized from the microbiota in your gut.  

Both K1 and K2 share a similar and common ring structure referred as a menadione. They also share a similar etiology in metabolic pathways of creating and activating proteins for blood coagulation and bone density. 

K2 has a higher bioavailability and absorption than K1. K1 is derived from plant sources and is poorly and inefficiently absorbed. Your body only uses a small percentage or fraction of the K1 found in plant sources. Phylloquinone is tightly bound to the plant’s chloroplasts, making it difficult to effectively digest. Supplementing K1 in its free form can improve bioavailability up to 80%. 

K1 Vs. K2: Takeaway

Both vitamin K1 and K2 have similar function, and molecular structure, however the source, absorption rates, tissue distribution, and bioavailability does differ. Vitamin K2 circulates in the body longer than K1, and has better bioavailability, since it is produced by the microbiota in the gut. Vitamin K plays an essential role in blood clotting, bone health, and heart health, providing a fundamental role in human biology. For optimal health, aim for eating at least one serving of vegetables per day preferably with a fat source, to improve absorption. Eating a well-balanced diet full of lean protein rich foods, vegetables, and healthy fats, will provide the adequate amounts of vitamin K you need in your diet.   


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