What is the role of vitamin K in my body?

Dariush Mozaffarian, MD
Internal Medicine
This relatively unknown vitamin got its name from "koagulation," the German word for coagulation (blood clotting), because vitamin K is essential for that process. Vitamin K also helps produce a key protein used in bone remodeling, and blocks substances that speed the breakdown of bone. The vitamin also helps regulate calcium excretion from the body in urine.

Vitamin K is found in green leafy vegetables, certain fruits, and commonly used cooking oils. People who shy away from salads and other greens may be low in this vitamin.
The name vitamin K comes from the German word koagulation, in reference to the vitamin’s first-known biological role in blood clotting. While blood has the remarkable ability to remain liquid even though it’s loaded with all sorts of solid material -- red and white blood cells, protein, vitamins, minerals and fat -- it can also become solid within seconds when a blood vessel breaks. This particular ability can spell the difference between life and death if you’re seriously injured -- and it requires vitamin K, which your body needs to make several blood proteins involved in clotting. If your body is short of vitamin K, your blood will clot very slowly, and you might develop symptoms, such as easy bruising, frequent nosebleeds or cuts that won’t stop bleeding.

This fat-soluble vitamin also helps strengthen bones, fight cancer and prevent heart disease. Vitamin K comes in a number of forms, including K1, which is found in plants, and K2, which is found in meats and eggs. Although K1 is the main dietary source for humans, K2 is the form found in the human body. Scientists suspect that the body converts K1 into K2. Unfortunately, 80 percent of men and 59 percent of women fail to get enough of this vital nutrient. Vitamin K deficiency is associated with bruising, extremely heavy menstrual periods and nosebleeds.
Michael T. Murray, ND
Naturopathic Medicine
One vitamin that is often neglected is vitamin K. Natural vitamin K from plants is called vitamin K1, phylloquinone, or phytonadione. Vitamin K2, or menaquinone, is derived from bacteria in the gut, and vitamin K3, or menadione, is a synthetic derivative.

The three vitamin Ks function similarly by helping with blood clotting, but for other important functions, vitamin K1 appears to be substantially superior. For example, vitamin K1 plays an important role in bone health. It is responsible for converting the bone protein osteocalcin, the inactive form, to its active form. Osteocalcin is the major non-collagen protein found in our bones. Vitamin K allows the osteocalcin molecule to join with calcium and hold it place within the bone.
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.