Patient education: Warfarin and your diet (The Basics)

What is warfarin? — Warfarin (brand name: Jantoven) is a medicine used to prevent or treat blood clots. It is also known as Coumadin, an old brand name.

What is vitamin K? — Vitamin K helps the body make proteins that are important for blood clotting and bone health. Most vitamin K comes from foods, especially plant foods like green leafy vegetables.

Why do I need to watch how much vitamin K I eat? — If you take warfarin, you need to eat about the same amount of vitamin K each day. That's because the amount of vitamin K in your diet affects the amount of warfarin you need to take. Do not take vitamin K supplements unless your doctor tells you to.

A dietitian (food expert) can help you manage the amount of vitamin K in your diet.

You also need to eat the same amount of vitamin K in your diet if you are on certain other medicines that work like warfarin. Examples include acenocoumarol and phenprocoumon.

What can I eat and drink while taking warfarin? — It is OK to eat foods with vitamin K in them. Many of these foods are a part of a healthy diet. It is important to eat about the same amount of high-vitamin K foods every day.

To keep a steady amount of vitamin K in your diet:

●Know how much vitamin K you are taking in each day. Try to eat the same number of servings each day, and each week, from the list of foods that are "high" and "medium" in vitamin K. Portion sizes can affect how much vitamin K you are getting.

●Be aware if you are eating more foods from the "high-vitamin K" group than you normally do.

●Vitamin K can also be found in some nutrition supplement drinks, natural products, multivitamins, and calcium supplements. It's OK to take the same multivitamin every day. If you use any of these, check the labels of each product so you know how much vitamin K is in them. If you are not sure, ask your doctor, nurse, pharmacist, or dietitian.

●If you make a big change in the amount of vitamin K foods that you eat, or if you cannot eat for 2 or more days, tell your doctor or nurse. They might want to do a blood test to find out if you need to change your warfarin dose.

What foods are high in vitamin K? — These foods have a lot of vitamin K. They have over 100 micrograms (mcg) of vitamin K in each serving.

●Dark green leafy vegetables including kale, spinach, Swiss chard, watercress, parsley, and green cabbage

●Other greens, including collard, mustard, turnip, beet, and dandelion greens

●Brussels sprouts

●Spinach noodles

●Fermented soy products, such as natto or tempeh

What foods are moderate in vitamin K? — These foods have a moderate or medium amount of vitamin K. They have between 10 and 100 mcg of vitamin K in each serving.

●Vegetables:

•Lighter-colored green leafy vegetables like iceberg lettuce, Romaine lettuce, green leaf lettuce, Chinese cabbage, and Savoy cabbage

•Broccoli

•Okra

•Rhubarb

•Celery

•Green peas and pea pods

•Vegetable juice

●Fruits:

•Blueberries

•Kiwis

•Grapes

•Pumpkin

•Pomegranate juice

●Other foods:

•Nutrition supplements (sample brand names: Boost, Ensure)

•Tuna fish in oil

•Spaghetti sauce

•Mung bean sprouts

•Soybeans

•Chicken breast

•Cashews

•Canola oil and soybean oil

•Caesar dressing, avocado dressing, creamy mayonnaise full-fat dressings, and full-fat creamy French salad dressings

•Pine nuts

What foods are low in vitamin K? — These foods have a small amount of vitamin K. They have less than 10 mcg of vitamin K in each serving.

●Vegetables:

•Fresh tomato

•Yellow and green snap beans

•Artichokes

•Cucumbers

•Cauliflower

•Carrots

•Green and red peppers

•Split peas and lima beans

•Winter and summer squash

•White and sweet potatoes

●Fruits:

•Fresh blackberries

•Prunes and raisins

•Red and green grapes

•Mangos

•Prune juice

•Papaya

•Pears

•Honeydew melon

•Peaches

•Figs

●Dairy:

•Mozzarella and cheddar cheese

•Milk and soy milk

•Margarine (blend, tub, or stick)

●Protein:

•Ground beef

•Ham

•Chicken liver

•Salmon

•Shrimp

•Mixed nuts

•Pumpkin seeds

•Duck

•Eggs

•Pinto and refried beans

●Other foods:

•Dill pickles

•Asian ginger, poppy seed, Italian, oil and vinegar, honey mustard, blue, Roquefort, Russian and Thousand Island salad dressings

•Olive oil

•Oat cereal

What else should I know? — Many medicines and herbal supplements can change how warfarin works in unpredictable ways.

●Tell your doctor, nurse, and pharmacist about all medicines you take. This includes prescription or over-the-counter medicines, natural products, and vitamins.

●It's also important to tell them about any health conditions you have. They can make sure that it is safe for you to take warfarin.

●Do not start, stop, or change the dose of any medicine or supplement without checking with your doctor.

Your doctor, nurse, pharmacist, or dietitian will tell you if you should follow other specific guidelines.

More on this topic

Patient education: Choosing an oral medicine for blood clots (The Basics)
Patient education: Taking oral medicines for blood clots (The Basics)
Patient education: Stroke (The Basics)
Patient education: Deep vein thrombosis (blood clot in the leg) (The Basics)
Patient education: Pulmonary embolism (blood clot in the lung) (The Basics)
Patient education: Atrial fibrillation (The Basics)
Patient education: Medicines for atrial fibrillation (The Basics)
Patient education: Prosthetic valves (The Basics)
Patient education: Prothrombin time and INR (PT/INR) (The Basics)

Patient education: Warfarin (Beyond the Basics)
Patient education: Deep vein thrombosis (DVT) (Beyond the Basics)
Patient education: Pulmonary embolism (Beyond the Basics)
Patient education: Atrial fibrillation (Beyond the Basics)
Patient education: Ischemic stroke treatment (Beyond the Basics)