Leafy Greens are OK For People on Warfarin
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A new study suggests that - despite doctor warnings to the contrary - you can eat leafy greens rich in vitamin K if you are taking the blood thinner warfarin.
Vitamin K aids clotting, so patients on the anti-clotting drug (or "anticoagulant") warfarin are often warned by their physicians to limit the amount of foods rich in the nutrient. These foods include green vegetables such as spinach, kale, broccoli, cabbage, Brussels sprouts and several others.
A new study however suggests that warfarin-treated patients may actually benefit from increasing their daily vitamin K intake. The results of the study were presented this year that the meeting of the American Society for Nutrition, in Baltimore.
The research team involved in this study sought out to test the if long-held notion that vitamin K really poses a problem for these patients. The study enrolled 46 patients, aged 32 to 85, all of whom were having trouble maintaining their anticoagulation levels. Half of the patients attended regular dietary counseling and cooking lessons. The other half went to counseling and cooking classes, but instructors in these classes promoted adding more green vegetables, as well as oils with vitamin K, to the diet.
The findings of the study were a surprise - six months later, 50% of people who had added more vitamin K to their diets were maintaining stable anticoagulation levels, compared to only 20% of those who did not add more of the vitamin. These results suggest that taking in more vitamin K, not less, might benefit patients on warfarin (Coumadin).
Based on the new findings, the study investigators now recommend a minimum of 90 micrograms of vitamin K per day for women and 120 micrograms per day for men. And it seems prudent that health care professionals stop advising warfarin-treated patients to avoid green vegetables. It should be noted that previous studies have shown a direct interaction between dietary vitamin K and the action of the drug, so it it is important that (higher) daily vitamin K intakes be as consistent as possible so that proper adjustments can be made to the dosing of this medication.
The accepted teachings to patients taking warfarin is to avoid vitamin K at all costs, to prevent any inhibition of warfarin by vitamin K. This new study showed that a reasonable and balanced diet involving vitamin K actually results in better outcomes.
The potential issues with vitamin K are actually less relevant today as there are now many new anticoagulant medications (include Rivaroxaban (Xarelto), Dabigatran (Pradaxa), and Apixaban (Eliquis) that do not interact with vitamin K and which do not need frequent blood monitoring.
If you are on warfarin, the key to minimizing food and drug interactions is through consistency, not avoidance. Eating a steady amount of vitamin K rich foods each day helps ensure a healthy, well-balanced body.