Date of Award


Degree Type


Degree Name

Departmental Honors


Nutrition, Dietetics, and Food Sciences

First Advisor

Megan Bunch


Background: Atrial fibrillation (AF) is the most commonly observed arrhythmia and is expected to increase to over 12 million in the next few decades. Patients with AF are at high risk of stroke due to the use of Coumadin in combination with stroke risk factors such as age >75 years, hypertension, diabetes, heart failure, and prior stroke or transient ischemic attack. Coumadin specifically targets the blood clotting cascade by inhibiting the regeneration of vitamin K needed for the activation of clotting factors. A 100 mcg increase in vitamin K intake over at least 4 days can reduce patient internationalized national ratio (INR) by 0.2 units. INR values outside of the recommended range of 2.0-3.5 increase the risk of intracranial bleeding and stroke. The objective of this study was to assess the understanding of the AF population related to their role in reducing the risks associated with Coumadin and the effects of proper understanding on stroke risk with a particular emphasis on patient understanding of the interaction between vitamin K and Coumadin.

Methods: Patients with known AF (n=75) who were receiving treatment from the Utah Heart Clinic and were currently taking Coumadin were asked to complete a one-time questionnaire of 52 questions related to Coumadin use and its’ drug-nutrient interactions. Data collected was analyzed to identify any vitamin K and diet knowledge deficits related to nutrition and Coumadin use.

Results: Sixty-eight of the patients had at least one risk factor for stroke with hypertension, the most common stroke risk factor (58.7% of the population). Age > 75 years was the second most common, followed by heart failure. Only 63.9% of the patient population had some understanding of diet/vitamin K and Coumadin use.

Conclusion: This study demonstrates a lack of patient knowledge regarding the interaction of Coumadin and nutrition/vitamin K in patients with additional stroke risk factors.

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Nutrition Commons