vitamin k
18 interactions related to vitamin k
parsley + warfarin
Fresh parsley is exceptionally vitamin K-dense; in cup-sized portions it provides a vitamin K load that can lower the INR in people on warfarin, reducing anticoagulation. The clinical effect depends on portion size and consistency.
green tea + warfarin
Green tea leaves contain vitamin K, the cofactor the liver needs to make the clotting factors warfarin works against. Large or fluctuating green tea intake can lower the INR and weaken warfarin's anticoagulant effect, as documented in a published case report. Moderate, steady intake is generally not a problem.
mustard greens + warfarin
Mustard greens are a dark leafy green that is very high in vitamin K1, the nutrient warfarin works against. Because warfarin blocks the recycling of vitamin K needed to make clotting factors, large or fluctuating intake of mustard greens can blunt warfarin's effect and lower your INR, while abruptly stopping a long-standing habit can push it up.
matcha + warfarin
Matcha is powdered whole green tea leaf, so each serving delivers more vitamin K than a brewed cup of green tea. Vitamin K is the cofactor warfarin works against, so starting, stopping, or varying a matcha habit can shift your INR and change how well warfarin protects you. The effect is documented for green tea and extends to matcha through its whole-leaf vitamin K content.
fat-soluble vitamins + dietary fat
Vitamins A, D, E, and K depend on bile-driven micelle formation in the small intestine to be absorbed, and that process is triggered by dietary fat. Taking these vitamins with a fat-free meal or on an empty stomach reduces how much you absorb, while taking them with a meal that contains some fat improves absorption. Controlled studies in vitamin D show meaningfully greater absorption when the supplement is taken with fat.
noni juice + warfarin
Noni juice (Morinda citrifolia) products vary widely in vitamin K content, and one published case of warfarin resistance was attributed to a high-vitamin K noni preparation. Noni has also been linked to drug-induced liver injury, which can secondarily destabilize warfarin. The interaction is real but rests on case reports rather than large studies.
collard greens + warfarin
Collard greens are one of the most vitamin-K-dense vegetables in the diet. Because warfarin works by blocking vitamin K, sudden increases or decreases in how much you eat can push your INR out of its therapeutic range. The goal is consistency, not avoidance.
spinach + warfarin
Spinach is one of the most concentrated dietary sources of vitamin K1, the very nutrient warfarin works against. Eating a lot of spinach, or suddenly changing how much you eat, can shift your INR out of its target range.
turnip greens + warfarin
Turnip greens are one of the most vitamin-K-rich vegetables on the table. Because warfarin works by blocking vitamin K-dependent clotting, large or fluctuating servings of turnip greens can blunt warfarin's effect and pull the INR below the therapeutic range, raising clot risk. The problem is inconsistency, not the food itself.
romaine + warfarin
Romaine lettuce is a moderate source of vitamin K1 (phylloquinone) - lower than dark cooking greens but meaningful at multi-cup salad servings. Large daily salads or romaine-heavy juices can supply enough vitamin K to oppose warfarin and nudge the INR downward. The risk is in changing your romaine habit, not in eating it.
microgreens + warfarin
Microgreens are the immature seedlings of vegetables and herbs, harvested when the first true leaves emerge. On a per-gram basis they concentrate vitamin K1 (phylloquinone), the form found in green plants that directly opposes warfarin. Brassica-family and amaranth microgreens are highest. A garnish-sized sprinkle is usually trivial, but daily salad-sized or smoothie portions are a meaningful vitamin K source that can shift the INR.
broccoli + warfarin
Broccoli is one of the most vitamin K1 (phylloquinone)-rich common vegetables, and vitamin K is the cofactor warfarin works by blocking. It is not about avoiding broccoli but about consistency: large swings in intake can move your INR and reduce warfarin's effect or raise bleeding risk.
sauerkraut + warfarin
Sauerkraut is fermented green cabbage and is a moderate source of vitamin K1, the nutrient that warfarin works against. Because vitamin K supplies the cofactor for the very clotting factors warfarin blocks, suddenly starting, stopping, or swinging your sauerkraut intake can shift your INR and loosen anticoagulation control. The goal on warfarin is consistent intake, not avoidance.
brazil nuts + warfarin
Brazil nuts contain essentially no vitamin K, so they do not antagonize warfarin or destabilize INR the way leafy greens can. Their notable feature is a very high selenium content, but selenium has no established effect on how warfarin works or is metabolized. The only practical reason to keep brazil nuts modest is selenium safety, not anticoagulation.
walnuts + warfarin
Walnuts contain only trace amounts of vitamin K and small quantities of plant-based omega-3 (alpha-linolenic acid). Normal food servings are unlikely to meaningfully shift INR. The standard warfarin principle applies: keep your intake reasonably consistent rather than swinging between none and very large daily portions.
swiss chard + warfarin
Swiss chard is a high-vitamin-K leafy green, and warfarin works by blocking vitamin K. Large, sudden swings in how much chard you eat can move your INR out of range, but the interaction is manageable: the goal is steady, consistent intake rather than avoidance.
pumpkin seeds + warfarin
Pumpkin seeds (pepitas) are a low-vitamin-K food and do not meaningfully affect warfarin in normal snack portions. The general warfarin principle of keeping vitamin-K intake consistent still applies, but pumpkin seeds are not a notable source.
kimchi + warfarin
Kimchi is fermented Napa cabbage and contains vitamin K1, the cofactor warfarin works against. Inconsistent kimchi intake can shift your INR and change warfarin's effect. The problem is not the food but the swings in how much you eat.