Coumadin Diet Recommendations

Published March 22, 2018
Leafy Vegetables In Kitchen Sink

When taking the drug coumadin, also known as Warfarin, it is important to know it interacts with some foods. Coumadin helps block the formation of dangerous blood clots in the body, and certain foods can interfere with its actions. Foods that impede coumadin's effects include those high in vitamin K, alcoholic beverages, grapefruit, and some herbal supplements.

Vitamin K

While taking coumadin, a person's vitamin K intake should be monitored. You do not need eliminate foods high in vitamin K from your diet. Instead, it is recommended to eat the same amount you consumed prior to starting the medication and keeping that amount consistent throughout the week. The reason this is an issue is because vitamin K does the opposite of coumadin; it promotes blood clotting. Excess vitamin K could decrease the effects of coumadin, but too little could have the opposite effect and make coumadin too effective.

Food Sources of Vitamin K

Foods high in vitamin K are typically green and leafy, but it is beneficial to know all possible foods sources of the vitamin.

  • Kale
  • Collard greens
  • Spinach
  • Turnip greens
  • Mustard greens
  • Dandelion greens
  • Beet greens
  • Swiss chard
  • Cress
  • Watercress
  • Escarole
  • Brussel sprouts
  • Broccoli

The key with these foods is to eat consistent amounts each day, which you can make simple by measuring the foods before you eat them and planning meals appropriately. For example, eating 1/2 cup of spinach every day provides a consistent intake. However, if you were not consuming foods high in vitamin K before starting coumadin, there is no need to start eating them now. Keep your diet as consistent as possible. Additionally, it has been found that cooking techniques don't impact the amount of vitamin K found in the food.


Another element that can influence coumadin metabolism is alcohol. It has been suggested that minor alcohol consumption may increase coumadin's anti-clotting effects by thinning the blood. However, chronic alcohol consumption can cause the body to increase the metabolism of coumadin, thus decreasing its anti-clotting effects. It's best to avoid alcohol consumption entirely or partake with extreme caution.


Grapefruit is known to interact with many medications, and coumadin is one of them. Avoid grapefruit and grapefruit juices while taking coumadin as they can decrease metabolism of the medication.


Daily multivitamins contain a wide variety of vitamins and minerals. Not all multivitamins contain vitamin K, but many do. Always conduct a double check to ensure your multivitamin does not contain vitamin K or you don't start a new vitamin or supplements containing vitamin K. Before taking a new vitamin supplement, talk with your doctor, pharmacist, or cardiologist.

Herbal Therapies

Some herbal products and treatments have been found to interact with coumadin. While taking this medication, limit intake of the following herbs.

  • Cranberry
  • Soya
  • St. John's wort
  • Danshen
  • Coenzyme Q10
  • Chinese angelica
  • Licorice
  • Ginger
  • Chamomile
  • Chitosan
  • Cannabis
  • Devil's claw
  • Horse chestnut
  • Ginkgo biloba
  • Garlic
  • Ginseng
  • Green tea
  • Lycium

Healthy Eating on Coumadin

While on coumadin, despite monitoring the above foods and beverages, you can easily maintain a healthy diet. A diet full of fruits, vegetables, dairy, lean protein, whole grains, and nuts and seeds is crucial to have good health on most medications, and coumadin is no different. Always speak with your doctor and registered dietitian about your diet before starting coumadin.

Coumadin and Your Diet

Coumadin can be an intimidating medication to begin. However, while on coumadin, managing your diet is as simple as monitoring vitamin K intake, limiting alcohol and grapefruit intake, and cautiously using herbal supplements. Coumadin can easily fit into any lifestyle without derailing a normal diet.

Coumadin Diet Recommendations