How to eat on Coumadin (warfarin)

Why should you be concerned about Vitamin K?

Vitamin K interacts with Coumadin (warfarin) and changes the way warfarin affects the blood. When you eat foods that are high in vitamin K, you can decrease the effect of warfarin. Likewise, eating less vitamin K can increase the effect of the medication. There are two approaches to managing the amount of Vitamin K in your diet: the first is to avoid all foods that are high in Vitamin K. The second is to consume about the same amount of Vitamin K each day. We take the second approach (here’s an article about that on The Right Dose of Vitamin K).

Since it’s best to keep your Vitamin K intake stable, it’s important that you do not make any major changes to your diet without speaking with your doctor. If you want to lose weight, eat a lower fat diet, or become a vegetarian, your doctor would want to know about these changes to help manage your warfarin.

Generally speaking, leafy green vegetables tend to contain higher amounts of vitamin K and one rule of thumb is to suspect that green veggies, cabbages and lettuces are high in Vitamin K. Certain vegetable oils, like canola oil, will have higher amounts of vitamin K.

Foods that are low in vitamin K include roots (like carrots), bulbs (onions, but not green onions/scallions), tubers, and many fruits and fruit juices. Cereals, grains, and other milled products are also low in vitamin K.