Vitamin K plays an essential role in bone metabolism and blood clotting. It’s a very important vitamin because it helps the coagulation (thickening) of blood to prevent hemorrhaging (uncontrollable bleeding) when a wound has occurred. Vitamin K is found in cabbage, spinach, soy beans, alfalfa, and tomatoes. While uncommon, signs of Vitamin K deficiency include bruising, gastrointestinal bleeding, and hemorrhages. Severe cases of Vitamin K deficiency can lead to osteoporosis.