Vitamin K helps your blood to clot by controlling the creation of clotting proteins in the liver. Coumadin works in part by decreasing the availability of vitamin K in the blood stream.
Because Coumadin (warfarin) works against the clotting properties in vitamin K, great care must be taken to balance Coumadin dosage against the levels of existing vitamin K in your body. Too much vitamin K, and the blood remains susceptible to clots; too little vitamin K, and a blood thinner like Coumadin can cause the blood to become too thin.
Foods with large quantities of vitamin K, like green leafy vegetables, reduce Coumadin’s effectiveness. Patients on a Coumadin regimen must keep their diet constant and not alter their intake of foods rich in vitamin K. Frequent blood tests help physicians determine changes in Coumadin dosage based on fluctuation of levels of vitamin K in the blood stream.
Patients who are on a Coumadin regimen to reduce their risk of stroke associated with atrial fibrillation must avoid consuming the following53:
| Artichoke | Asparagus | Avocado |
| Broccoli | Brussels Sprouts | Cabbage |
| Cauliflower | Collard Greens | Green Onions |
| Green Tomato | Kale | Lettuce |
| Mustard Greens | Okra | Spinach |
| Swiss chard | Turnip Greens | Watercress |
| Garlic | Gingko Biloba |
| Ginseng | Feverfew |
| Fish Oil Capsules | Turmeric |
| St. Jons Wort | Chondrotin Sulfate |
| Vitamin A | Vitamin E |
| Coriander | Parsley |
| Beef | Pork |
| Chicken Livers |
| Canola | Olive |
| Chick Peas | Natto |
| Soybeans & Soybean Products, including Tofu |
| Alcohol | Cranberry Juice |
| Grapefruit | Green Tea |
| Seaweed |
Coumadin® is a registered trademark of Bristol-Myers Squibb. For the most recent information about Coumadin®, prescription information and precautions, please visit www.coumadin.com.
