Updated: Jul 6, 2020
Reference: Information taken from VCH (Vancouver Coastal Health) patient handout EA.485.D54
Vitamin K and certain foods decrease the effectiveness of this type of blood thinner, Coumadin and Warfarin. Better control of your blood clotting can be achieved if the amount of vitamin K in your diet remains relatively consistent. People respond to Warfarin (Coumadin) differently. Close monitoring of your INR is important.
Foods high in Vitamin K do not need to be avoided, but keeping your intake of these foods consistent is important.
Dark Leafy Greens are the highest in Vitamin K. ½ a cup of cooked greens contains a lot more Vitamin than ½ a cup of uncooked greens. So keeping it raw or cooked consistent is a good idea as well. Ones that are high include - beet greens, collards,
kale, mustard greens, parsley, spinach, turnip greens.
Other vegetables that have contain Vitamin K and can vary slightly raw or cooked (especially the leafy greens) and the portion should be kept constant as well throughout the week - asparagus, avocado, broccoli, Brussel sprouts, butter lettuce, cabbage, dandelion greens, endive, green leaf lettuce, green onions, green peas, iceberg lettuce, Romaine lettuce, sauerkraut, seaweed and watercress.
If you do not normally eat foods high in Vitamin K do not suddenly eat a large amount. Inform our physician if you are going to change your Vitamin K pattern of vegetables (increase or decrease) significantly.
Foods to avoid - Natto (Japanese fermented soybean)
Other foods that can affect this medication, use in moderation - Cranberry and pomegranate juice (limit to ½ cup), 1 to 2 cups of green tea, 1 to 2 alcoholic drinks per day, avoid omega-3 supplements and be careful with other herbal products - especially turmeric (curcumin).
Talk to your dietitian for more information.