Uses of Vitamin K - Blood clotting - Bone formation (in co-ordination with Calcium) - Antidote for Warfarin Deficiency of Vitamin K The deficiency of Vitamin K is super rare. There are two types of Vitamin K i.e. K1 and K2. Body obtains Vitamin K1 from food and recycles it continuously. As far as Vitamin K2 is concerned, body produces it on its own. Therefore, the deficiency of Vitamin K is rare. Deficiency is caused by - Fat malabsorption - Vitamin K deficient diet - Excessive use of anticoagulants e.g. Warfarin - Excessive use of antibiotics The symptoms of Vitamin K are - Easy scratches and bruises - Small cuts under nails - Easy bleeding of mucous membranes - Tar-colored stools with blood Dosage of Vitamin K Adult men = 120 micrograms/day Adult women, pregnant or breastfeeding = 90 micrograms/day