Coumadin (warfarin) and Your Diet

Read on if you are one of the four million Americans who take the blood thinner warfarin for an irregular heart rhythm or other cardiovascular condition. Without this medication, you may be more likely to suffer from blood clots, which can block the flow of blood to the brain or the heart. This can cause serious and sometimes fatal health problems.

The downside of this medication is that it must be monitored very closely. If you are on warfarin, you need to pay careful attention to your lifestyle, including your diet and any supplements you may be taking.

The effect of food
Vitamin K
Foods that contain vitamin K are the ones you need to watch the most. Vitamin K is a fat-soluble vitamin that helps your blood to clot. If there is too much vitamin K in your body, though, it interferes with the action of the blood thinner.

Many wrongly believe that people on warfarin should avoid all foods with vitamin K. In fact, eating a different amount of vitamin K from day to day can cause dangerous changes in your clotting time. It's best to maintain a limited but consistent intake of vitamin K in your diet. This does not mean that you have to eat the same thing every day. Rather, aim to balance your food intake of vitamin K.

Get the right amount of vitamin K
The highest concentration of vitamin K is found in green leafy vegetables. Follow the guidelines below to ensure you get adequate, but not excess amounts of the following foods which are rich in nutrients:

Eat no more than one serving a day of these: (300 mcg to 600 mcg of vitamin K per 1/2 cup serving) Kale, cooked Spinach, cooked Turnip greens, cooked Collard greens, cooked Swiss chard, cooked Parsley, raw Mustard greens, cooked

Consistency is the key
Do not suddenly eat more or fewer foods containing vitamin K.
Stick with your usual routine. For instance, if you normally have a salad for lunch every day and a serving of broccoli or Brussels sprouts with dinner, you may keep doing so. The goal is to try to take in about the same amount of vitamin K every day. If you change your eating patterns, you may need a medication adjustment, so always check with your doctor before you change your diet.

Vitamins and herbs
Do not take any supplements without asking your doctor first. All of the following can affect your medication:

• Anise
• Dong quai
• Omega 3-fatty acids in fish oil
• Garlic pills
• Gingko
• St. John's wort
• American ginseng
• Vitamin E
• Alfalfa
• Coenzyme Q10
• Multivitamins with vitamin K

Other considerations

• Do not finish more than two drinks of alcohol at a sitting. Alcohol increases the effect of warfarin. Your doctor may advise you to avoid alcohol completely.
• Eat a normal, balanced diet while you are taking this medicine. Do not go on a low-calorie diet or make major changes in your eating habits unless you first check with your doctor.
• If you are unable to eat for several days or if you are vomiting, have diarrhea or a fever, call your doctor. This may require a change in your medication.
• Check with your doctor or pharmacist before taking any other medication. Other medications (over-the-counter and prescription) can interact with warfarin.

Related Articles A Powerful Weapon Against Blood Clots Atrial Fibrillation on the Rise What Is Stroke?

External Sources National Heart Lung and Blood Institute. An NIH conference on dietary supplements, coagulation, and antithrombotic therapies. Accessed November 13, 2007. National Institutes of Health. Important information to know when you are taking: coumadin and vitamin K. Accessed November 14, 2007.

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