Vitamin K helps ensure the effectiveness of certain proteins in the body that are responsible for clotting and coagulation. It is found in high quantities in leafy green vegetables and dark berries. Children, in particular, need vitamin K for proper growth and development. Specifically, vitamin K helps develop strong bones and healthy tissues. A person who has a vitamin K deficiency will suffer from prolonged bleeding because the condition affects the blood’s ability to clot, resulting in excessive and uncontrollable blood loss. Vitamin K deficiency also causes weak bones and joints. Young children do not have a sufficient amount of vitamin K in their system, so they receive a shot of the supplement shortly after birth.