Dietary Considerations in Warfarin Patients
Warfarin acts by impairing the utilization of Vitamin K. The liver requires Vitamin K for the manufacturing of certain key proteins in the native clotting mechanism. When Vitamin K is not made available, these clotting factors are not manufactured, and blood clotting is impaired. At the same time, oral intake of Vitamin K will thus counteract the medicinal purpose of Warfarin, essentially acting as the antidote for Warfarin. Sudden intake of large amounts of Vitamin K can diminish the effect of Warfarin, permitting the blood to clot. Some physicians place Warfarin patients on strict Low-Vitamin-K diets. Foods that are high in Vitamin K are discouraged. However, dietary restrictions rarely succeed over a long period of time. Most patients return to eating their favorite foods, gradually at first. Thus the more prudent approach for Warfarin maintenance is to adjust the medication, not the diet. That is one of the very reasons for repeating the Pro-Time until a steady dose is found that provides the right anticoagulation regardless of the dietary intake of the patient. For your information, the following lists presents foods known to be high in
Vitamin K.
- Kale
- Spinach
- Broccoli
- Turnip greens
- Cauliflower
- Chick peas
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- Brussels sprouts
- Green tea
- Beef, pork, or chicken livers
- Soybean oil
- Soy protein products (including tofu)
- Vitamins A & E (large doses)
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If your regular diet already contains these food items, Don't Change Your Eating Habits. Consistency in your daily eating pattern is the key. If you move to a new climate, or change your eating habits for any other reason, a new series of Pro-Times will be needed to make certain that your Warfarin requirement has not changed. However, even if it has changed, the best option is to change the dose which you take.
The information provided in this educational forum is solely for your information, and is not intended to replace actual recommendations or advice given by your treating physician.
Your Diet & Vitamin K
Warfarin works to keep your blood from clotting by decreasing the availability of Vitamin K. Vitamin K helps your blood to clot. These are opposing actions. Excessive Vitamin K intake can interfere with the Warfarin and allow your blood to remain susceptible to clots. Likewise, if you eat too little Vitamin K, the excess medication may cause your blood to become too thin. Your medication will be adjusted to the amount of Vitamin K typically in your diet. If you suddenly increase or decrease the amount of Vitamin K in your diet, your medication will not work properly.
A healthy, low fat diet following the Food Guide Pyramid is the best diet to follow. It is important for you to keep the Vitamin K content of your diet consistent. The amount of Vitamin K you eat affects the amount of Warfarin you require. Be sure to tell your healthcare provider if you change your diet. The medication will need to be adjusted to the amount of Vitamin K in your diet.
Some foods that are high in Vitamin K (i.e., leafy, green vegetables, broccoli, and cauliflower) can contribute to a healthy diet. Your efforts should be focused on keeping your intake of Vitamin K consistent from day to day. The first step is to evaluate your typical intake of Vitamin K foods by reviewing the food list in this packet.
Although there is little information about the effects of cooking, freezing, or drying on the Vitamin K content of foods, it appears that the Vitamin K content of cooked, frozen, or dried foods is about the same as fresh foods.
Evaluate your typical Vitamin K intake by reviewing the food list provided. The list contains foods that are known to be high in Vitamin K, as well as a few others that are not very high, but are often asked about by Warfarin patients. If you do not see a particular food on the list, it most likely contains very little Vitamin K, however, be sure to ask you dietitian about the food if you are concerned.
First, review the list to find foods that you are presently eating. Each list is identical. The first organizes foods from the highest Vitamin K content to lowest, while the second is in alphabetical order. Observe the amount of Vitamin K contained in the foods you eat. If you typically eat a larger portion than what is listed, be sure to increase the Vitamin K value proportionally. (i.e., there is 40ug of Vitamin K in ½ cup of lettuce, but you eat 2 cups worth in your salad, so you would actually have 160ug of Vitamin K in total). Add up the total amount of vitamin K that you typically consume in a day. Whatever it may be, 100, 200, 300, 400ug, etc., your job is to keep this daily intake as consistent as possible. By selecting combinations of foods, and/or adjusting portion sizes you should be able to consume about the same amount of Vitamin K each day.
If you should ever decide to dramatically change your typical daily intake of Vitamin K, be sure to inform your Doctor or pharmacist BEFORE making the change. They will most likely need to adjust your Warfarin dosage.
CAUTION - The following should be taken only with your physician's approval, because they also thin your blood, thus increasing the effect of your medication: alcohol, garlic pills, fish oil capsules, Vitamin E. Vitamin K tablets can also interfere with your Warfarin medication. Be sure to get your physician's approval, if you take Vitamin K tablets or a multi-vitamin pill with Vitamin K included. If you should have any additional questions or concerns regarding your daily intake of Vitamin K, please contact a dietitian at phone number (210) 292-7587 or 7472.
Highest to Lowest Vitamin K Content (Listed by food item, portion size and Vitamin K content)
- Seaweed (Nori), 2 sheets (shredded), 511
- Turnip greens, ½ cup, 470
- Collard greens, ½ cup, 440
- Spinach, ½ cup, 360
- Brussels sprouts, ½ cup, 289
- Kale, ½ cup, 270
- Swiss chard, ½ cup, 249
- Green tea, 1 oz (leaves)**, 199
- Parsley, ½ cup, 162
- Green scallion, ½ cup, 155
- Broccoli, ½ cup, 113
- Cauliflower, ½ cup, 96
- Cabbage, ½ cup, 80-100
- Liver (beef, pork, chicken), 3.5 oz, 80-100
- Soybean oil, 1 Tbsp, 76
- Endive, ½ cup, 69
- Avocado, ½ cup, 57
- Coriander, ½ cup, 52
- Asparagus, ½ cup, 51
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- Mustard greens, ½ cup, 51
- Green tomato, ½ cup, 50
- Watercress, ½ cup, 42
- Artichoke, ½ cup, 42
- Lettuce, ½ cup, 40
- Okra, ½ cup, 40
- Soybeans, ½ cup, 34
- Green beans, ½ cup, 33
- Nettle leaves, ½ cup, 31
- Red tomato, ½ cup, 25
- Garbanzo beans, ½ cup, 22
- Green peas, ½ cup, 22
- Alfalfa sprouts, ½ cup, 16
- Celery, ½ cup, 16
- Cucumber (sliced with peel), ½ cup, 6
- Green pepper, ½ cup, 5
- Tofu, ½ cup, 2.5
- Lima beans, ½ cup, 2
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Vitamin K Content by Food Item (Listed by food item, portion size and Vitamin K content)
- Alfalfa sprouts, ½ cup, 16
- Artichoke, ½ cup, 42
- Asparagus, ½ cup, 51
- Avocado, ½ cup, 57
- Broccoli, ½ cup, 113
- Brussels sprouts, ½ cup, 289
- Cabbage, ½ cup, 80-100
- Cauliflower, ½ cup, 96
- Celery, ½ cup, 16
- Collard greens, ½ cup, 440
- Coriander, ½ cup, 52
- Cucumber (sliced with peel), ½ cup, 6
- Endive, ½ cup, 69
- Garbanzo beans, ½ cup, 22
- Green beans, ½ cup, 33
- Green peas, ½ cup, 22
- Green pepper, ½ cup, 5
- Green scallion, ½ cup, 155
- Green tea, 1 oz (leaves)**, 199
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- Green tomato, ½ cup, 50
- Kale, ½ cup, 270
- Lettuce, ½ cup, 40
- Lima beans, ½ cup, 2
- Liver (beef, pork, chicken), 3.5 oz, 80-100
- Mustard greens, ½ cup, 51
- Nettle leaves, ½ cup, 31
- Okra, ½ cup, 40
- Parsley, ½ cup, 162
- Red tomato, ½ cup, 25
- Seaweed (Nori), 2 sheets (shredded), 511
- Soybean oil, 1 Tbsp, 76
- Soybeans, ½ cup, 34
- Spinach, ½ cup, 360
- Swiss chard, ½ cup, 249
- Tofu, ½ cup, 2.5
- Turnip greens, ½ cup, 470
- Watercress, ½ cup, 42
- Ensure, 8-oz can, 18
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** Current analytical findings indicate that the brew from green tea leaves has negligible Vitamin K content.
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