          
              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.
          
          
