VITAMIN K

          

            

         

              Vitamin K is a fat-soluble vitamin usually formed in

          the body by intestinal bacteria but also available from

          some plant and animal sources.

         

              Function: Essential in the formation of prothrombin, a

          substance necessary for proper clotting of blood, and at

          least five other blood-clotting factors.

         

              Sources: All green leafy vegetables (including lettuce,

          spinach, kale, and cabbage), eggs, meats, cereal grain

          products, fruits, and milk and dairy products.

         

              Deficiency: vitamin K deficiency may cause bleeding

          disorders in premature infants with inadequate amounts of

          stored vitamin K, and in people on blood-thinning

          medications and those with fat malabsorption syndromes.

         

              Excess: Natural forms have no known toxic effects;

          large doses of the synthetic version, menadione, and its

          derivatives cause anemia and kernicterus, a condition

          characterized by jaundice, in infants.