Based on WHO | Do dairy products like milk, yogurt, or cheese interact with warfarin or affect my INR?

Most dairy products like milk, yogurt, and most cheeses do not have enough vitamin K to meaningfully change warfarin’s effect for most people, so they typically do not affect INR if your overall diet is consistent. ^[1] However, warfarin is very sensitive to changes in vitamin K intake, so sudden increases in high–vitamin K foods (mainly leafy greens and certain oils not typical dairy) can lower your INR and make warfarin less effective. ^{[2] [3]}

How warfarin and diet interact

• Warfarin works by blocking vitamin K–dependent clotting factor activation, so dietary vitamin K can counteract its effect. ^[4] Keeping your vitamin K intake steady from day to day helps keep your INR stable. ^[1]
• Clinically, changes in vitamin K intake especially big swings are a well‑recognized reason for INR drift. ^[5] Consistency, rather than strict avoidance, is the key. ^[3]

Dairy foods and vitamin K

• Typical dairy (milk, plain yogurt, most soft cheeses) is generally low in vitamin K compared with leafy greens and certain vegetable oils, so it usually does not have a significant independent effect on INR. ^{[2] [3]}
• The major foods that raise vitamin K intake are leafy green vegetables (e.g., spinach, kale), some cruciferous vegetables (broccoli, Brussels sprouts), and certain oils (soybean, canola) rather than dairy products. ^{[6] [7]}

When dairy could matter

• If a dairy product is fortified or made with ingredients rich in vitamin K (for example, products containing added plant oils), a sudden increase in servings could, in theory, lower INR; maintaining a steady pattern would minimize this risk. ^{[6] [3]}
• In infants, vitamin K–supplemented formulas can blunt warfarin’s effect, while exclusive human milk may make infants more sensitive to warfarin; this reflects vitamin K content differences, but it does not generally apply to adults. ^[8]
• The biggest concern is not dairy itself but any abrupt dietary change; even seasonal diet shifts can modestly influence INR, which is why steady habits are recommended. ^{[4] [9]}

Practical guidance you can use

• Keep your overall diet consistent, including the amount and types of dairy you usually consume, to help keep INR stable. ^[1]
• You do not need to avoid milk, yogurt, or cheese solely because you take warfarin, but try not to drastically change your typical portions from one week to the next. ^[3]
• If you plan to start or stop a diet high in vitamin K (for example, a green smoothie program or cooking more with soybean/canola oil), let your care team know, as your warfarin dose or INR monitoring schedule may need adjustment. ^{[2] [4]}
• Continue routine INR checks; warfarin has a narrow therapeutic range, and monitoring is essential as diet and other factors can shift INR. ^[4]

Other common food and drink considerations

• Consistent vitamin K intake is the priority; avoid large, sudden increases in leafy greens and certain oils. ^[6]
• Some items can interact unpredictably with warfarin (e.g., cranberry products, grapefruit, green tea, alcohol, and some supplements), so discuss any major changes with your clinician. ^{[6] [10]}

Bottom line

• Most dairy products are low in vitamin K and, when eaten consistently, are unlikely to meaningfully alter your INR on warfarin. ^{[2] [3]}
• The most important step is to keep your day‑to‑day vitamin K intake steady and continue regular INR monitoring with your healthcare team. ^{[1] [4]}