green tea
4 interactions related to green tea
matcha + warfarin
Matcha is powdered whole green tea leaf, so each serving delivers far more vitamin K than a normal brewed cup. Vitamin K is the cofactor warfarin antagonises, so large or fluctuating matcha intake can lower INR and reduce the anticoagulant effect, similar to the documented green tea-warfarin case report.
green tea + warfarin
Green tea leaves contain vitamin K, which is a cofactor for hepatic synthesis of the clotting factors that warfarin inhibits. Large or fluctuating intake of green tea can lower INR and reduce the anticoagulant effect of warfarin, as documented in a published case report.
green tea + folate
Green tea and EGCG inhibit the proton-coupled folate transporter (PCFT) in the small intestine and inhibit dihydrofolate reductase, the enzyme that converts folic acid into its active form. In humans, concomitant green tea reduced folic acid Cmax by about 58% and AUC by about 44%.
green tea + iron
Green tea catechins, especially epigallocatechin-3-gallate (EGCG), chelate non-heme iron in the gut and form insoluble complexes that reduce intestinal absorption. The effect is dose-related and most pronounced when tea is consumed with iron-containing meals or supplements.