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Warfarin & diet

Warfarin is a medication used to prevent blood clots from forming or growing larger in your blood and blood vessels. It's essential for patients on warfarin to be aware of the potential interactions with foods, drinks, and supplements, as these can affect how the medication works.

Understanding the Role of Vitamin K

Vitamin K plays a significant role in blood clotting, and warfarin works by interfering with the action of vitamin K. Therefore, maintaining a consistent intake of vitamin K from your diet can help to keep the effects of warfarin stable.

General Tips for Managing Warfarin Interactions

  1. Keep a consistent diet, especially regarding foods, drinks and supplements high in Vitamin K.

  2. Ask me for a referral to a dietitian

  3. Keep a food diary

  4. Consistency is key to maintaining your INR levels, you do not have to avoid foods that contain vitamin K altogether.

Foods and Warfarin

High and Moderate Vitamin K Foods to consume consistently

  1. Green leafy vegetables: Kale, spinach, turnip greens, collards, Swiss chard, mustard greens, parsley, lettuce

  2. Other vegetables: Brussels sprouts, broccoli, cabbage, asparagus, green beans, carrots, peas

  3. Certain vegetable oils: Canola, soybean

Low Vitamin K Foods that are generally safe in varying amounts

  1. Root vegetables (excluding carrots): Potatoes, sweet potatoes, radishes

  2. Fruits: Apples, bananas, grapes, oranges

  3. Breads and cereals (excluding those with added vitamin K)

  4. Meat and fish (excluding liver and other organ meats which can be high in vitamin K)

Drinks and Warfarin

Drinks that may strengthen warfarin (increase risk of bleeding)

  1. Alcohol

Drinks that may weaken warfarin (increase risk of clotting)

  1. Cranberry Products

  2. Green tea


Supplements and Warfarin

Supplements that may strengthen warfarin (increased risk bleeding)

  1. Fish oil or Omega-3 fatty acids

  2. Garlic

  3. Gingko Biloba

  4. Ginger

  5. Glucosamine

  6. Vitamin E at high doses

Supplements that may weaken warfarin (increase risk of clotting)

  1. Coenzyme Q10 (CoQ10)

  2. St. John's Wort

  3. Ginseng

  4. Multivitamins that contain Vitamin K

  5. Green tea extracts

  6. Some meal replacement shakes or bars that may be fortified with Vitamin K

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