Based on WHO | Is it true that bananas are high in vitamin K and should be limited or avoided while taking warfarin?

Bananas are low in vitamin K, and they do not need to be routinely limited or avoided while taking warfarin as long as your overall vitamin K intake is consistent. ^[1] Warfarin’s effect is reduced mainly by large or sudden increases in vitamin K–rich foods like leafy green vegetables, not by fruits like bananas that contain very little vitamin K. ^{[2] [3]}

Why vitamin K matters with warfarin

• Warfarin works by blocking vitamin K’s role in making clotting factors; if you suddenly eat a lot more vitamin K, warfarin can seem weaker and your INR may drop. ^{[4] [2]}
• Because of this, guidance emphasizes keeping your vitamin K intake steady from day to day rather than avoiding it entirely. ^{[1] [5]}

Are bananas high in vitamin K?

• Lists of vitamin K–rich foods focus on greens such as kale, spinach, collards, Swiss chard, broccoli, Brussels sprouts, and similar vegetables not bananas. ^[3]
• Practical patient instructions warn against large amounts of leafy greens and certain oils because they are high in vitamin K; bananas are not included among high‑K foods. ^{[2] [6]}

What to do in real life

• You can generally keep eating bananas in normal portions if you enjoy them, while avoiding big day‑to‑day swings in vitamin K intake overall. ^[1]
• The key is consistency: avoid sudden changes in how much vitamin K‑rich food you eat in a week, because that can alter how much warfarin you need. ^{[4] [5]}
• If you plan a major diet shift (for example, starting daily large salads or green smoothies), talk with your clinician so your INR can be monitored and your dose adjusted if needed. ^{[2] [4]}

Other diet pointers with warfarin

• Be cautious with very high‑vitamin K foods (leafy greens and some vegetable oils) and aim for a steady pattern rather than complete avoidance. ^{[2] [7]}
• Certain drinks and products can also interact with warfarin (for example, alcohol, grapefruit, green tea, and cranberry) and may need moderation. ^{[8] [3]}

Bottom line

• Bananas are not a high‑vitamin K food, and there is no standard recommendation to limit or avoid them on warfarin when eaten in typical amounts. ^[3]
• Focus on keeping your total vitamin K intake consistent and monitoring INR as advised by your care team. ^{[1] [4]}