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Warfarin diet: What foods should I avoid?
By Mayo Clinic staffOriginal Article: http://www.mayoclinic.com/health/warfarin/AN00455

- With Mayo Clinic emeritus hypertension specialist
Sheldon G. Sheps, M.D.
read biographyclose windowBiography of
Sheldon G. Sheps, M.D.
Sheldon Sheps, M.D.
Dr. Sheldon Sheps, emeritus professor of medicine and former chair of the Division of Nephrology and Hypertension in the Department of Medicine at Mayo Clinic, has been with Mayo Clinic since 1960.
Dr. Sheps, a Winnipeg, Manitoba, native, is board certified in internal medicine and specializes in hypertension and peripheral vascular diseases. He developed a multidisciplinary approach with specially trained nurses, dietitians, technicians and educators to help form a team approach to the treatment of patients with abnormal blood pressure.
"I have always believed in involving the patient and family in their health care," Dr. Sheps says. "I have asked for their understanding of the illness and issues and for participation in decisions. The Web is a natural extension of that, and now many more people can be informed."
Dr. Sheps chaired the sixth working group, and he participated in the fourth, fifth and seventh groups that developed the then-latest guidelines for hypertension under the auspices of the National Heart, Lung, and Blood Institute (NHLBI). He helped write the latest American Heart Association (AHA) report on blood pressure measurement. He chaired an AHA group that produced an online accreditation for blood pressure measurement for health professionals.
Dr. Sheps has co-authored books, newsletters, CD-ROMs and other Mayo Clinic health information material. He joined Mayo Clinic's Web team in 1998. He was medical editor-in-chief of both editions of the "Mayo Clinic on High Blood Pressure" book; the last edition was published in 2003. He was also medical editor-in-chief of "Mayo Clinic 5 Steps to Controlling High Blood Pressure," published in 2008.
In addition, Dr. Sheps was section editor for each of the first three editions of "Hypertension Primer" for the American Heart Association.
Dr. Sheps was also chairman of the Science Base Subcommittee and the National High Blood Pressure Education Program, and he was a consultant to the Hypertension Initiative of the World Health Organization. In 1997, he was honored with the Individual Achievement Award on the 25th anniversary of the National High Blood Pressure Education Program of NHLBI. In 2009, he was honored as a Distinguished Mayo Alumnus.
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Question
Warfarin diet: What foods should I avoid?
Can you tell me what I should eat while I am taking warfarin (Coumadin)? What foods should I avoid?
Answer
from Sheldon G. Sheps, M.D.
Warfarin is a blood-thinning medication that helps treat and prevent blood clots. There is no specific warfarin (Coumadin) diet. However, certain foods and beverages can make it so warfarin doesn't effectively prevent 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 average daily allowance 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:
- Kale
- Spinach
- Brussels sprouts
- Parsley
- Collard greens
- Mustard greens
- Chard
- 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:
- Cranberry juice
- Alcohol
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. These signs and symptoms may mean you need a different dose of warfarin.
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- deAssis MC, et al. Improved oral anticoagulation after a dietary vitamin K-guided strategy: A randomized controlled trial. Circulation. 2009;120:1115.
- Nutescu EA, et al. Warfarin and its interactions with foods, herbs and other dietary supplements. Expert Opinions on Drug Safety. 2006;5:433.
- Ford SK, et al. Vitamin K supplementation to decrease variability of international normalized ratio in patients on vitamin K antagonists: A literature review. Current Opinion in Hematology. 2008;15:504.
- Valentine KA, et al. Outpatient management of oral anticoagulation. http://www.uptodate.com/index. Accessed June 14, 2012.
- Ansell J, et al. Pharmacology and management of the vitamin K antagonists: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines (8th edition). Chest. 2008;130:160S.
- Coumadin and vitamin K. National Institutes of Health. http://www.cc.nih.gov/ccc/patient_education/drug_nutrient/coumadin1.pdf. Accessed June 14, 2012.
- Warfarin natural product and drug interactions. Natural Medicines Comprehensive Database. http://www.naturaldatabase.com. Accessed June 14, 2012.


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