The main concern is supplementation. People taking vitamin K antagonist anticoagulants such as warfarin should not start vitamin K supplements without medical supervision because changes in intake can alter INR and medication effect. Individuals with serious liver disease or malabsorption may need individualized plans. Pregnancy, breastfeeding, childhood, and polypharmacy also warrant clinician guidance. Dietary vitamin K from foods is generally appropriate; the debate is mostly about additional high-dose supplementation.