Vitamin K and Warfarin: What You Should Know

When your body senses an injury, a series of action occurs to form a blood clot that can protect the injured area. Vitamin K is one of the substances in your blood that is required for this reaction to occur.

Having blood clots, increases your risk your risk for heart attacks, stroke, or other serious complications and warfarin also known as Coumadin slows the action of vitamin K thereby slowing blood clot information. 


  • 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.

The takeaway point is that for warfarin to be effective, you must keep your dietary intake of vitamin k consistent. It is not necessary cut off your intake because:

  • greatly decreasing your vitamin k intake, is dangerous because your blood can become too thin putting you at increased risk for bleeding; on the other hand, greatly increasing your intake leaves you at a risk for forming blood clots

Food Source

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

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

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

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

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

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