Foods that contain Vitamin K include kale, collard greens, spinach, Brussels sprouts, strawberries and broccoli. Many plant greens, such as mustard greens, beet greens and dandelion greens, are also a top source of the nutrient.
Vitamin K is not a single vitamin, but a group of compounds that includes Vitamin K1 and Vitamin K2. Vitamin K1 is the main form of Vitamin K and is found in dark, leafy greens. Vitamin K2 is in eggs, meats and cheeses.
Healthy adult women should get 90 micrograms of Vitamin K per day, while adult men should get 120 micrograms per day. Most people get adequate Vitamin K in their diets, and so it is not typically used as a dietary supplement.
Vitamin K helps prevent excessive bleeding and plays a role in clotting. Vitamin K deficiencies are relatively rare in adults, although they do happen occasionally in newborn infants. Adults with digestive tract ailments, such as Celiac or Crohn's disease, may be more at risk for developing a Vitamin K deficiency. Those who drink alcoholic beverages regularly or are malnourished are also at an elevated risk.
There are some risks associated with too much Vitamin K, and individuals should not take a supplement unless directed by a doctor. People with heart problems or clotting disorders should especially watch their Vitamin K intake.