Warfarin, your diet, and vitamin K foods

What do I need to know about my diet?

Some foods you eat affect the way warfarin works in your body. Try and keep eating what you normally do. It is most important to eat a healthy, consistent, and balanced diet.

Certain foods and dietary supplements have vitamin K. Vitamin K works against warfarin.

  • If you eat more vitamin K, it can decrease your INR.
  • If you eat less vitamin K, it can increase your INR.

Important things about vitamin K:

  • Keep your diet of foods high in vitamin K about the same.
  • You do not need to avoid foods high in vitamin K.
  • Check with your health-care provider before making any big changes in your diet.
  • Contact your health-care provider if there are sudden or big changes in your diet due to illness.

What is high in vitamin K?

The most common foods that have high vitamin K are green leafy vegetables such as kale, collard greens, broccoli, spinach, cabbage, and lettuce.

Other foods that could affect warfarin may include beef liver or other animal liver products.

Vitamin K can also be found in certain nutrition supplements, such as:

  • Boost, Ensure, and Slim Fast
  • Certain multiple vitamins and Viactiv calcium chews
  • Tobacco, such as cigarettes and chewing tobacco

If you have any questions about vitamin K, please ask your health-care provider.

Vitamin K foods

It is important to try and keep the same amount of vitamin K in your diet. All foods are okay, but do not make big changes to how much or what you eat. It is important to check with your health-care provider before making any big changes to your diet.

Very high in vitamin K (more than 800 mcg per serving)

Food Portion Size
Kale 1 cup
Spinach (frozen, chopped, cooked, boiled, or drained) 1 cup
Collards 1 cup
Turnip greens 1 cup

High in vitamin K (400 to 800 mcg per serving)

Food Portion Size
Beet greens 1 cup
Dandelion greens 1 cup
Mustard greens 1 cup

Medium in vitamin K (80 to 400 mcg per serving)

Food Portion Size
Spinach (raw, leaf) 1 cup
Brussel sprouts 1 cup
Broccoli 1 cup
Onions (springs or scallions, tops and bulb) 1 cup
Lettuce (iceberg) 1 head
Lettuce (green leaf) 1 cup
Cabbage 1 cup
Asparagus 1 cup
Endive 1cup
Parsley 10 sprigs
Okra 1 cup

Tables were adapted from the USDA National Nutrient database for Standard Reference



Last reviewed: 
August 2017

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