Can you tell me what I should eat while I am taking warfarin (Coumadin, Jantoven)? What foods should I avoid?
Answers from Sheldon G. Sheps, M.D.
Warfarin is a blood-thinning medication that helps treat and prevent blood clots. There is no specific warfarin diet. However, certain foods and beverages can make warfarin less effective in preventing blood clots. It's important to pay attention to what you eat while taking warfarin.
One nutrient that can lessen warfarin's effectiveness is vitamin K. It's important to be consistent in how much vitamin K you get daily. The adequate intake level of vitamin K for adult men is 120 micrograms (mcg). For adult women, it's 90 mcg. While eating small amounts of foods that are rich in vitamin K shouldn't cause a problem, avoid eating or drinking large amounts of:
- Brussels sprouts
- Collard greens
- Mustard greens
- Green tea
Certain drinks can increase the effect of warfarin, leading to bleeding problems. Avoid or drink only small amounts of these drinks when taking warfarin:
Talk to your doctor before making any major changes in your diet and before starting any over-the-counter medications, vitamins or herbal supplements. If you are unable to eat for several days or have ongoing stomach upset, diarrhea or fever, consult your doctor.
June 26, 2015
See more Expert Answers
- Mahtani KR, et al. Vitamin K for improved anticoagulation control in patients receiving warfarin (review). Cochrane Database of Systemic Reviews. http://onlinelibrary.wiley.com/doi/10.1002/14651858.CD009917.pub2/abstract. Accessed June 3, 2015.
- Ge B, et al. Updates on the clinical evidenced herb-warfarin interactions. Evidence-Based Complementary and Alternative Medicine. 2014;2014:957362.
- Chang C-H, et al. A practical approach to minimize the interaction of dietary vitamin K with warfarin. Journal of Clinical Pharmacy and Therapeutics. 2014;39:56.
- Hull RD, et al. Outpatient management of anticoagulation with warfarin. http://www.uptodate.com/home. Accessed June 4, 2015.
- Holbrook A, et al. Evidence-based management of anticoagulant therapy: Antithrombotic therapy and prevention of thrombosis, 9th ed.: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. Chest. 2012;141(suppl):e152S.
- Important information to know when you are taking: warfarin (Coumadin) and vitamin K. National Institutes of Health Clinical Center Drug-Nutrient Interaction Task Force. http://ods.od.nih.gov/factsheets/list-all/VitaminK/. Accessed June 4, 2015.
- A patient's guide to taking warfarin. American Heart Association. http://www.heart.org/HEARTORG/Conditions/Arrhythmia/PreventionTreatmentofArrhythmia/A-Patients-Guide-to-Taking-Warfarin_UCM_444996_Article.jsp. Accessed June 4, 2015.
- Vitamin K fact sheet for health professionals. National Institutes of Health Office of Dietary Supplements. http://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/. Accessed June 9, 2015.