Vitamin K is needed for the production of prothrombin, which is necessary for blood clotting. It is also essential for bone formation and repair;  it is necessary for the synthesis of osteocalcin, the protein in bone tissue on which calcium crystalizes. Consequently, it may help prevent osteoporosis. In addition, it may protect the vascular system by preventing calcification in the arteries. The liver is a very efficient extractor of vitamin K, which is used to make clotting factors for the blood. Some investigators have argued  that  the current DRI's may be insufficient to meet the needs of the other tissues in the body. 

Vitamin K plays an important role in the intestines and aids in converting glucose into glycogen for storage in the liver, promoting healthy liver function. It may increase resistance to infection in children and help prevent cancers that target the inner linings of the organs. It aids in promoting longevity. A deficiency of this vitamin can cause abnormal and/or internal bleeding.