Human Nutrition 3(3+0)

Lesson 23 : Vitamin K

Physiological and biochemical functions

• Vitamin K is essential for blood clotting mechanism.
• Vitamin K administration leads to an increase in the prothrombin level. In vitamin K deficiency, prothrombin level is reduced.

Source: Wardlaw et al. (1992)

Figure: Blood clot formation requires vitamin K.

• Vitamin K is involved in the carboxylation of glutamic residue in prothrombin. Vitamin K antagonists like dicumarol block this reaction. The main site of prothrombin synthesis is liver.