Can you tell me what I should eat while I am taking warfarin (Coumadin, Jantoven)? What foods should I avoid?
Answer From Francisco Lopez-Jimenez, M.D.
Warfarin is a blood-thinning medication that helps treat and prevent blood clots. There's no special diet for people who take warfarin. However, certain foods and drinks can make warfarin work not as well at preventing blood clots. It's important to pay attention to what you eat while taking warfarin.
For example, vitamin K can make warfarin less effective. So, it's important to get about the same amount of vitamin K every day. The recommended intake level of vitamin K for adult men is 120 micrograms (mcg). For adult women, it's 90 mcg.
To keep vitamin K intake consistent, avoid changing the amounts of vitamin K-rich foods or drinks you have from day to day or week to week. Vitamin K-rich foods include:
- Brussels sprouts
- Collard greens
- Mustard green
- Turnip greens
- Swiss chard
- Chamomile or green tea
Certain drinks when taking warfarin might lead to bleeding problems. Avoid or drink only small amounts of these when taking warfarin:
- Cranberry juice
- Grapefruit juice
Talk to your health care provider before making major changes in your diet and before starting medications, vitamins or herbal supplements. If you can't eat for several days or have ongoing stomach upset, diarrhea or fever, call your provider.
Francisco Lopez-Jimenez, M.D.
July 01, 2022
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- Hull RD, et al. Warfarin and other VKAs: Dosing and adverse effects. https://www.uptodate.com/contents/search. Accessed April 18, 2022.
- San San Tan C., et al. Warfarin and food, herbal or dietary supplements: A systematic review. The British Pharmacological Society. 2020; doi:10.1111/bcp.14404.
- Yu CP, et al. Bidirectional influences of cranberry on the pharmacokinetics and pharmacodynamics of warfarin with mechanism elucidation. Nutrients. 2021; doi:10.3390/nu13093219.
- Vitamin K fact sheet for health professionals. National Institutes of Health Office of Dietary Supplements. http://ods.od.nih.gov/factsheets/VitaminK-HealthProfessional/. Accessed April 18, 2022.
- Quick reference guide to foods that are high and low in Vitamin K. American Heart Association. https://www.heart.org/en/health-topics/arrhythmia/prevention--treatment-of-arrhythmia/a-patients-guide-to-taking-warfarin. Accessed April 18, 2022.