What dietary substances can increase the INR with Warfarin therapy?

Garlic is known to have properties that can influence blood coagulation. When consumed, garlic can potentially enhance the anticoagulant effect of Warfarin, leading to an increased International Normalized Ratio (INR). This occurs due to garlic's ability to inhibit platelet aggregation and possibly its effect on the pharmacokinetics of Warfarin, which can heighten the risk of bleeding when INR rises.

In contrast, other substances such as pepper, onion, and turmeric do not have the same notable effects on INR in the context of Warfarin therapy. Pepper may not significantly impact coagulation, onion's effects are generally considered mild in comparison, and while turmeric has some anticoagulant properties, its effect on INR in a clinical context is not as pronounced as that of garlic. Therefore, garlic stands out as the dietary substance with a clearer potential for increasing INR when taken alongside Warfarin therapy.