Based on NIH | Is it true that eating rice can interact with warfarin and affect INR levels?

Eating plain rice does not meaningfully interact with warfarin or change INR for most people. The well‑documented food interactions with warfarin are primarily tied to vitamin K intake (especially leafy green vegetables and certain oils), alcohol, and a handful of specific foods/drinks like cranberry products and grapefruit not staple grains like rice. ^{[1] [2]}

Key takeaways

• Rice (white or brown) is very low in vitamin K and is not listed among foods known to raise or lower INR in clinical guidance. ^[1]
• The most important dietary factor for warfarin is keeping vitamin K intake consistent; large swings in vitamin K can lower or raise INR. ^[3]
• Established dietary cautions include leafy green vegetables (high vitamin K), certain vegetable oils, alcohol, cranberry products, black licorice, grapefruit, and green tea. Rice is not among these. ^{[1] [2] [4]}

Why vitamin K matters with warfarin

Warfarin works by blocking vitamin K–dependent clotting factors, so eating a lot more vitamin K than usual can lower INR (blood becomes “thicker”), while suddenly eating far less can raise INR (higher bleeding risk). ^{[1] [3]} Keeping your vitamin K intake steady day to day helps maintain a stable INR and a stable warfarin dose. ^{[5] [6]}

What the evidence and guidelines emphasize

• Authoritative medication guides consistently warn about “leafy, green vegetables” and “certain vegetable oils” because of their high vitamin K content; they do not flag grains or rice. ^{[1] [3]}
• Patient‑facing guidance highlights consistency in vitamin K intake and lists common interacting foods/drinks (e.g., alcohol, cranberry, grapefruit, green tea), with no mention of rice. ^{[2] [4]}
• Research and clinical reviews identify “foods high in vitamin K” as the relevant dietary inhibitor of warfarin effect; staple grains like rice are not identified as clinically significant interactants. ^{[7] [8]}

Practical advice if you eat rice

• You can generally continue eating rice as part of your normal diet without expecting INR changes due to the rice itself. ^[1]
• Focus on consistency overall: if you add or remove large amounts of vitamin K–rich foods (e.g., spinach, kale, broccoli) or oils (soybean, canola), let your care team know so your INR can be monitored and your warfarin dose adjusted if needed. ^{[1] [3]}
• Be cautious with alcohol and certain beverages/supplements (cranberry products, grapefruit juice, green tea, black licorice), which may affect warfarin. ^{[2] [4]}

Bottom line

There is no good evidence that rice directly alters warfarin activity or INR, and it is not listed among foods of concern in standard warfarin diet guidance; maintaining a consistent intake of vitamin K–rich foods remains the key strategy. ^{[1] [3] [2]}