Vitamin K is one of the essential vitamins found in a healthy balanced diet. Your liver uses vitamin K to produce clotting factors, and as such plays a role in your body's natural clotting process. Warfarin works against vitamin K and reduces the amount of clotting factors your liver can produce.
Vitamin K is found in some of the foods that we eat, so our diet plays a big part in how much vitamin K is in our body. Changes in the amount of vitamin K in your body will mean that your body needs different amounts of warfarin to have the same effect on your clotting factors. For example, if you reduce the amount of vitamin K you eat, you will have less in your body for warfarin to work against, so even less clotting factors will be made and your INR will increase.
The important thing to remember is not to make radical changes to your diet. If you keep eating the same things as you have always eaten then your vitamin K levels will stay the same and your warfarin shouldn't be affected. Consistency is the key!
This is NOT a list of foods to avoid or a comprehensive list of all foods containing vitamin K. It provides an idea of those foods with high and moderate vitamin K content as an aid to helping you maintain a consistent dietary intake.
* cranberry juice consumption has been linked with increased bleeding with warfarin