Summer Foods and Warfarin

summer foods that can impact the anticoagulant warfarin

Vitamin K is an essential nutrient for human beings. It helps create various proteins that are needed for blood clotting and the building of bones. Our blood needs vitamin K to help clot wounds. We can’t and shouldn’t eliminate all clotting, but excessive clotting or clotting in unwanted places, such as blood clots in the deep veins of the arms or legs (deep vein thrombosis or DVT) or life-threatening blood clots in the lungs (pulmonary embolism or PE), are a serious problem. Vitamin K is also (surprisingly) in some summer foods and can impact the anticoagulant warfarin.

Vitamin K and Warfarin

If you take the blood thinner warfarin, you probably have a fairly good understanding of how diet and nutrition, particularly vitamin K, can impact your medication. A sudden change in the amount of vitamin K you eat can cause dangerous bleeding (if you consume less) or blood clots (if you consume more).

People who take warfarin have regular blood monitoring to ensure they are taking the right amount of warfarin. A prothrombin time (PT) test measures how long it takes for a clot to form in a blood sample. An INR (international normalized ratio) is a type of calculation based on PT test results. A PT/INR test helps find out if your blood is clotting normally. It also checks to see if Coumadin/warfarin is working the way it should. An INR value that is too low may mean a person is at increased risk for blood clots and an INR value that is too low may mean a person is at increased risk for clotting. Vitamin K can interfere with how warfarin works and cause the INR value to fluctuate. 

The major foods to be aware of are green leafy vegetables like spinach, broccoli, and kale. It can be frustrating to try to eat a healthy and balanced diet if you take warfarin because some of the most nutritious foods also contain high amounts of vitamin K. It’s critical that people who take warfarin find a balance by aiming to consume consistent amounts of vitamin K and avoid sudden and drastic changes to their diets.

Even if you don’t like or choose to avoid vegetables with typically high vitamin K content, what common summer foods contain higher amounts of vitamin K that could potentially impact your dosage of warfarin? The answer surprised me.

Summer Foods and Warfarin

Vitamin K is a staple in my diet, even though I take warfarin, so I eat it as part of my daily diet (usually spinach or peppers). With summer in full swing – and as a new home gardener – I decided to change up my diet to add in more fresh fruits and vegetables. For breakfast, I had a spinach, avocado, and blueberry smoothie, and for lunch was a cucumber salad. I had freshly sautéed carrots with dinner and a handful of fresh cherries for dessert. It was Saturday night, so I also indulged in one glass of delightfully sweet Peach Moscato on the patio where I settled in to search the Internet for a few new recipes. It was a fantastic feeling to be so summery all around.

That was short-lived though. Much to my surprise, I discovered that cucumbers – along with blueberries, avocado, carrots, and cherries – have a higher vitamin K content. I already knew that alcohol can impact anticoagulants, but an occasional glass does typically not interfere with my medication. However, almost everything else I ate that day also had a higher vitamin K content. 

I felt myself sliding into a panic about it, and I immediately deduced that I should never try anything new ever again – or stay off the Internet completely. There was nothing I could do to change what I already. After taking a few deep breaths, I began to calm down and developed an actionable plan to address my situation.

I have a standing (always on file) order for my INR at the hospital near my house, so I went first thing Monday morning to have it checked. It was within my normal range, perhaps because I already consume vitamin K daily. I felt a lot better knowing for sure that my warfarin dose did not need to be adjusted to accommodate my dietary choices. Tuesday I had a regular appointment with my hematologist so we discussed the next time I should get my INR checked.

Summer Foods That Are (Maybe Surprisingly) High in Vitamin K

  • Blueberries 
  • Cherries 
  • Cucumber 
  • Cabbage
  • Green Snap Beans
  • Kiwi
  • Pickles
  • Avocados 
  • Blackberries 
  • Pomegranate 
  • Carrots 
  • Red Bell Peppers
  • Grapes

Vitamin K content listed by food.

Enjoying Summertime Foods

If you want to change your diet to include summer foods and take warfarin, or if you make changes unexpectedly as I did, be aware of your body and check in with your medical providers if you have any concerns. Be prepared to check your INR perhaps more frequently than usual or for the possibility that your warfarin dose might need to change temporally to get you back on track. If you experience any unusual bleeding while taking an anticoagulant, contact your doctor or go to the hospital right away.

You can still eat a healthy diet and enjoy summer while being aware of the foods (and drinks) that can impact your health. 

There is hope for healing from blood clots, and you are not alone.

Reader Writes In: What foods would you add to the list? How do you manage warfarin and summertime eating?

Share your thoughts in the comments!

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