Coumadin and Vitamin K

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Q: I am on coumadin and not supposed to eat leafy green vegetables. I have vitamins which contains 10 mcg of vitamin K in them. How much would this affect my international normalized ratio? If I do not eat a lot of green leafy vegetables or salads, would that be okay?

Norma, Rockville Centre, New York

A: Vitamin K is essential to produce blood clotting factors, and people with deficiencies have a bleeding tendency. Coumadin interferes with the action of vitamin K and impedes the time it would take for your body to form a clot. Vitamin K counteracts the action of coumadin.

Very high sources of vitamin K deliver more than 400 mcg (per serving) and include the classic leafy green vegetables: kale, swiss chard, seaweed. Mild sources of vitamin K deliver 60-400 mcg and include avocado, broccoli, and lettuce.

The RDA recommends 90 mcg for the average adult female. It is important to take in consistent amounts of vitamin K while on Coumadin. The PT/INR will be more susceptible to change if your vitamin K intake fluctuates significantly. Update your clinic with your typical intake of vitamin K and eat consistent amounts of mild vitamin K rich foods. I would advise continuing to eat healthy vegetables but monitoring the ratio of which foods tend to be more concentrated and matching your intake day-to-day.

Overall, the vitamin K content of your tablet is fine as long as you are aware of foods that are concentrated sources of vitamin K (the leafy green vegetables) and can stay consistent in your intake.

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