Increasing vitamin K intake may help not hinder patients on warfarin


  • Mary Corcoran
  • Univadis Medical News
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New research suggests that increasing vitamin K intake may help rather than hinder patients taking warfarin. 

As part of a new trial, researchers investigated whether increasing dietary vitamin K intake by ≥150 µg/day improves anti-coagulation stability of warfarin-treated patients with a history of international normalised ratio (INR) instability. Patients were randomised to an intervention group (VK) and received dietary counselling to increase their vitamin K intake by ≥150 µg/day through specific food choices, recipes and cooking strategies, while patients from the control (C) group received general dietary information of similar intensity. 

A total of 49 participants completed the study. After six months, 50 per cent of those counselled to increase their vitamin K intake were maintaining stable anti-coagulation levels, compared with around 20 per cent of those who received the general nutritional counselling. 

"I think all warfarin-treated patients would benefit from increasing their daily vitamin K intake,” said lead study author Guylaine Ferland. "That said, given the direct interaction between dietary vitamin K and the action of the drug, it is important that (higher) daily vitamin K intakes be as consistent as possible."

Ferland added: “Our hope is that healthcare professionals will stop advising warfarin-treated patients to avoid green vegetables.” 

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