Coumadin, also known as warfarin, is an anticoagulant, or blood-thinning, medication. If you are at an increased risk of developing blood clots that could block blood flow to your heart, brain or other parts of your body, your doctor may prescribe Coumadin. While taking Coumadin, pay attention to what you eat, as certain foods may interact with your medication. Closely monitoring your vitamin K intake is extremely important, as this nutrient can decrease Coumadin's effectiveness.
Role of Vitamin K
Vitamin K is involved in blood clotting, and Coumadin works by decreasing vitamin K-dependent clotting activity within the liver. This helps to prolong the time it takes for a clot to form within the body. Although you do not need to avoid vitamin K, maintaining a consistent daily intake of vitamin K is essential for Coumadin to be effective. Significant increases or decreases in vitamin K in your diet will alter the drug's effectiveness. If your diet changes, make sure to consult your physician, as your medication may need to be adjusted as well. Coumadin.com provides a list of the vitamin K content, in micrograms, for a variety of foods; this is a useful tool for tracking the amount of vitamin K in your diet.
Foods High in Vitamin K
The Daily Value for vitamin K is 80 micrograms, based on a 2,000-calorie diet, although you may not consume exactly that amount. According to the National Institutes of Health, foods are considered to be high in vitamin K if they provide 200% or more of the Daily Value. Leafy green vegetables including boiled kale, boiled turnip greens, boiled spinach, boiled collard greens, raw parsley, boiled mustard greens and boiled Swiss chard are all high in vitamin K. Scallions or spring onions are also high in vitamin K. Foods considered high in vitamin K should be limited to only 1 serving per day.
Foods Moderately High in Vitamin K
If a food provides 60 to 199% of the Daily Value per serving, it is labeled as moderately high in vitamin K, according to the National Institutes of Health. A half-cup of boiled Brussels sprouts provides 190% of the Daily Value for vitamin K. Other foods considered moderately high in vitamin K include 1 cup servings of raw spinach, raw turnip greens, raw green leaf lettuce, raw broccoli, raw endive lettuce and raw romaine lettuce. Since these foods are moderately high in vitamin K, you should consume no more than 3 servings per day of these foods.
