Warfarin diet: what food affect my INR? There are a number of natural supplements and food products, which may affect the level of warfarin in different ways. For example, research has shown that the popular herbal product with ginseng may decrease the effects of warfarin, Ginkgo biloba may increase its effects. Page 1 of 1 Warfarin and Your Diet Introduction Warfarin is a medicine used to prevent the formation of blood clots. People who have an artificial heart Warfarin is an anticoagulant, which means that it increases the time it takes for your blood to clot. It works by reducing the effects of vitamin K, which is a vitamin your body uses in the process of blood-clotting. Advice on alcohol While alcohol can be a source of pleasure and enjoyment, drinking too much or at the wrong time, can cause problems when on warfarin. Warfarin is the most widely prescribed anticoagulant in the UK. Find out why you might take it, possible side effects, and what else you need to know. Find out why you might take it, possible side effects, and what else you need to know. Warfarin interferes with the way a certain clotting factor helps your blood to clot. A clotting factor is a substance that helps the blood clump together to form a clot. Warfarin ‘thins’ the blood, and increases the time it takes to clot. Changes to your diet, when Changes to your diet, when taking warfarin, can have an effect on the ‘thinness’ of your blood. 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. Foods Low in Vitamin K for a Warfarin (Coumadin) Diet Written by Daisy Whitbread, MScN Last Updated: December 14th, 2018 If you are taking an anticoagulant or a blood thinner, like Warfarin (Coumadin), then it is important to keep your PT/INR (Prothrombin Time and International Normalized Ratio) levels stable. info@afa.org.uk Warfarin and diet This factsheet is intended to help those aff ected by atrial fi brillation understand more about the interaction between warfarin and certain types of food, to help patients maintain a stable INR level. Many people with atrial fi brillation may find that warfarin therapy is recommended to thin the blood and reduce their risk of stroke.