ABSTRACT
Introduction: The effectiveness of oral anticoagulation therapy with warfarin (a vitamin K antagonist) in the treatment of thromboembolic disease, including stroke prophylaxis in patients with atrial fibrillation is well recognised. However, warfarin has a narrow therapeutic window and an unpredictable anticoagulation response, which make it difficult to achieve and maintain optimal anticoagulation. Various dietary factors, including sudden changes in eating patterns, can significantly alter anticoagulation control, thereby potentially exposing patients to the risk of bleeding or thromboembolic complications. Dietary vitamin K intake is a particularly important factor, given the mechanism of action of warfarin.
Areas covered: In this article, we cover the sources of vitamin K and their potential effect of dietary vitamin K on anticoagulation response to warfarin. We also discuss the results of studies on the effect of vitamin K supplementation on anticoagulation stability.
Expert commentary: A stable dietary vitamin K, promoted by daily oral vitamin K supplementation, can improve anticoagulation stability in patients on warfarin therapy. There is experimental evidence in animals that dietary vitamin K affects anticoagulation response to the direct thrombin inhibitor, ximelagatran. Whether dietary vitamin K affects anticoagulation response to the currently licensed direct oral anticoagulants (DOACs) in man remains to be investigated.
Declaration of interest
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.