Warfarin Diet and Vitamin K
Vitamin K is an essential nutrient for the formation of prothrombin and other clotting factors in the liver to make blood clot and to stop bleeding. Warfarin, a blood thinning medication, prevents vitamin K from participating in the production process of clotting factors.As a result, it reduces the amount of clotting factors leading to blood thinning, and it helps to lower the risk of abnormal blood clot formation. In other words, vitamin K works against Warfarin.
When you are on Warfarin, you need to maintain a consistent vitamin K intake on a daily basis to avoid affecting the efficacy of Warfarin. Doctor could adjust the dosage of Warfarin for you based on your eating habits in order to maintain the INR* within a safe and effective range, reaching optimal blood viscosity.
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INR (International Normalized Ratio)
– an index obtained from a blood test to evaluate the blood’s ability to clot
You may choose to eat vitamin K containing foods according to your usual eating habits. For example, if you like to eat high vitamin K-containing dark leafy vegetables regularly before you are put on warfarin, you do not need to stop eating these immediately; instead, you could maintain similar amounts of daily vitamin K intake and let your doctor to adjust the Warfarin dosage, if necessary. Please seek advice from your doctor and dietitian first if you intend to change your diet pattern drastically, e.g. energy restriction for weight loss.
Food Sources of Vitamin K
Food group containing higher amount of vitamin K
(Intake should be consistent)
Other Foods/ Drinks that may interacts with Warfarin
Some foods/ drinks do not or contain only a small amount of vitamin K but may interact with Warfarin affecting its effectiveness as a blood thinner. Please avoid or decrease intake of these foods/ drinks according to healthcare professionals’ recommendation.
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