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Drug/Nutrient Interactions: Warfarin and Vitamin K

Warfarin (brand name, Coumadin) is a medication ordered for you by your doctor. It is a medication that is used to keep your blood from clotting. A blood clot could cause a serious health problem for you. You must take Warfarin as your doctor has ordered.  

Vitamin K is an important nutrient in the body and is found in some foods that you eat.  The table below contains a list of these foods.  Vitamin K has the opposite effect of Warfarin and helps the blood to clot.  

The foods in the list below may be consumed; however, the key to managing your diet when taking Warfarin is to keep the intake of these foods at a constant level. In other words, you should not change your eating habits dramatically. If you regularly eat foods from the list, continue to do that; and if you do not eat them, don’t start while you are taking Warfarin. If you decide to suddenly change your intake of these foods, it will affect the way that the drug works.  

General Guidelines and Recommendations:  

  • Vitamin K counteracts how Warfarin works
  • Take Warfarin as ordered by your doctor
  • Continue to eat your usual diet and maintain a consistent intake of food from the list that you would normally eat.  
  • If you need to make dramatic diet changes, such as with illness, a weight loss diet, or any other reason, call your doctor.  Your dosage of Warfarin may need to be adjusted.  
  • Do not take vitamin supplements (especially A, E, K and C) while on this medication.
  • Do not take herbal supplements including garlic oil supplements, fish oil supplements, ginger supplements or onion extract pills while taking Warfarin.  
  • Do not drink herbal teas and green tea while taking Warfarin
  • Avoid alcohol
  • You may be advised not to consume large amounts of cranberry products such as cranberry juice, syrup, and relish. Follow your doctor’s recommendations.  

Vitamin K Food List

If you normally eat these foods, maintain the same intake while you take Warfarin.
  • Asparagus
  • Avocado
  • Beans pod, raw
  • Broccoli
  • Brussel Sprouts
  • Cabbage (white, red), Sauerkraut, Coleslaw
  • Cauliflower
  • Chickpeas (Garbanzo beans)
  • Collard Greens
  • Cucumber Peel
  • Egg Yolk
  • Green Onions
  • Green Tea Leaves
  • Greens:  Kale, Mustard, Swiss Chard, Turnip
  • Lettuce (most) including Romaine, Watercress, Endive
  • Lentils
  • Liver:  Beef, Chicken, and Pork
  • Mint
  • Multivitamins
  • Parsley
  • Pickles
  • Pistachio Nuts
  • Salad oils – canola, soybean, olive
  • Seaweed (Sushi rolls) – (contains an extremely high level of Vitamin K)
  • Soybeans, Tofu
  • Spinach
  • Snack chips containing Olestra

Breastfeeding moms:  

Warfarin may be transferred to your baby through breast milk. This could cause bleeding in your baby. Talk with your doctor about the best way to feed the baby if you have to take Warfarin while breastfeeding.

Disclaimer: This information is not intended to substitute or replace the professional medical advice you receive from your child's physician. The content provided on this page is for informational purposes only, and was not designed to diagnose or treat a health problem or disease. Please consult your child's physician with any questions or concerns you may have regarding a medical condition.

Reviewed: 08/2009