Coumadin is a brand name of warfarin, an anticoagulant drug prescribed to prevent blood clots in people who have suffered a heart attack or have had heart valve replacement surgery. It may also be prescribed for other conditions as determined by your doctor. Vitamin K can intensify Coumadin's clotting effects and increase the risk of bleeding, or it can stop Coumadin from working properly and lead to blood clots. Doctors instruct patients either to avoid or limit foods that are high in vitamin K, such as certain types of vegetables and fruits, when taking this medication.
Leafy Green Vegetables
Dark, green leafy vegetables contain the highest amount of vitamin K of any food source. Some health practitioners tell patients who are taking Coumadin not to eat all leafy green vegetables while they are on the medication. Leafy green vegetables to avoid include kale, spinach, green leaf and romaine lettuce, parsley, endive and watercress. Turnip, beat, collard, mustard and dandelion greens also have high amounts of vitamin K. Some doctors believe that it is most important to keep your diet consistent by eating the same types and portions of vegetables you usually eat so your vitamin K levels do not fluctuate. This does not mean you should eat a lot of leafy green vegetables, just that you should limit your intake of these foods and not vary the amount that you eat from week to week.
Cruciferous Vegetables
Cruciferous vegetables are vitamin-K rich, so patients taking Coumadin should follow their doctor's instructions and either limit or avoid eating these vegetables, which include broccoli, cauliflower and Brussels sprouts. Foods such as cole slaw and sauerkraut that are made with these vegetables should also be avoided.
Legumes
Legumes have only moderate amounts of vitamin K, but some doctors advise their patients not to eat certain legumes such as bean pods, chickpeas, lentils, black-eyed peas or mung beans and mung sprouts. Soy, soybeans and soy products may also be problematic for people taking Coumadin. Soymilk and foods containing soy may cause Coumadin levels to increase in some cases and to decrease in others, according to a University of Michigan website.
Stalk Vegetables
Stalk vegetables, such as celery, asparagus and rhubarb, contain moderate amounts of vitamin K. If you are taking Coumadin, you should refrain from eating large quantities of these vegetables or foods made with them such as rhubarb pie.
Fruits
Most fruits have low amounts of vitamin K and can be eaten safely by people taking Coumadin. Do not overindulge in fruits that contain moderate amounts of this vitamin. These include blueberries, dried or stewed plums, kiwi fruit and grapes. Mangoes, if eaten too frequently, may interfere with the effectiveness of Coumadin.
