Vitamin K The Green Leafy Vitamin

Vitamin K

The Green Leafy Vitamin

 

Vitamin K is a fat-soluble vitamin needed for blood  coagulation. Coagulation refers to the process of blood clotting. Vitamin K was discovered by a Danish scientist, Henrik Dam, in the late 1920s. He discovered a factor that was causing excessive bleeding and was missing from some diets. He published his work in a German journal and called the new coagulation vitamin Koagulationsvitamin. The initial letter in this word is how vitamin K got its name.

Vitamin K and Blood Clotting

Blood must flow freely and not clot unless there is a break in a blood vessel. Clotting is normally triggered by a rough edge in a blood vessel, such as a cut artery. The liver synthesizes several proteins important in blood clotting including prothrombin and fibrinogen. These two proteins circulate in blood. One of the first steps in
blood clotting is triggered by the formation of thrombin from prothrombin. Thrombin then accelerates the conversion of fibrinogen to  fibrin, which consists of fine threads that tangle together to form a blood clot. Vitamin K is necessary in order for the liver to synthesize prothrombin. Vitamin K converts the glutamic acid that is in prothrombin, enabling it to bind to calcium. Without adequate vitamin K, prothrombin production slows, leading to a bleeding tendency.

There are several other proteins involved in blood clotting that are activated by vitamin K. Balance and control are important parts of blood clotting. In addition to speeding blood clotting, vitamin K also assists in creating proteins that slow blood clotting. Vitamin K is needed to synthesize two proteins, protein C and protein S, which are important inhibitors of coagulation. Protein S is also synthesized by the blood vessel walls where it has a role as a coagulation inhibitor.

Vitamin K and Bone Mineralization

Bones are formed by bone-forming cells called osteoblasts. The osteoblast cells synthesize osteocalcin, under the direction of the active form of vitamin D, calcitriol. Vitamin K is needed to enable osteocalcin to bind minerals to bones. Vitamin K is used as a coenzyme to convert three glutamic acid residues in osteocalcin that enable bone mineralization.

Higher vitamin K levels may be protective against osteoporosis and age-related fracture. Several studies have found a correlation between higher vitamin K levels and lowered risk of hip fracture. However, since leafy green vegetables are the primary source of vitamin K, this protective effect could be from other nutrients, such as the calcium or magnesium in green leafy vegetables.