A vitamin K shortage can actually cause excessive bleeding, nosebleeds, and severe bruises. Vitamin K is a crucial supplement that your body needs in order to be able to coagulate blood efficiently. If this sounds familiar to you, you should visit your doctor and receive the same treatment. The bacteria in your colon produce half of the required vitamin K; you can supplement this with a regular diet of green vegetables and dairy products. It is crucial that you consult your doctor if you have any of the above symptoms because vitamin K is necessary for the formation of blood clots.