After my mom had heart surgery, my “nagging daughter” mode went up quite a few notches. While chatting on the phone one day, I scolded her for not eating more leafy greens like spinach and kale. That’s when she told me those nutrient-rich veggies are a little too rich when it comes to vitamin K and can negate the affect of her prescribed blood thinner.
That might sound like she was just trying to get me off her back about eating healthier, but it turns out she was right. According to the Mayo Clinic, vitamin K is a natural coagulant. That means eating a lot of foods with heavier amounts of it have the potential to counteract blood thinners, like Warfarin, and cause blood clots.
However, it’s not an excuse to totally exclude certain vitamin K-rich veggies from your diet. The Mayo Clinic simply warns against eating large amounts of food with particularly high levels. They also list the daily recommended value of vitamin K for women as 90 mcg (micrograms). Of course, everyone is different. So if you’ve been prescribed blood thinners, it’s important to talk with your doctor about how much vitamin K is too much for your diet.
To give you a better idea of exactly which foods you might need to careful about, we consulted the US Department of Agriculture (USDA) FoodData Central for some nutritional breakdowns.
Take a look below to see which foods have the highest levels of vitamin K that might counteract blood thinners.
Vitamin K per cup: 37.8 mcg
Enjoying some fresh kiwi as a snack once in a while shouldn't set you back too much, but it won't leave much room in the daily recommended amount of vitamin K for the rest of your meals.
Vitamin K per cup: 59.4 mcg
This is the same amount you'll have in a cup of either fresh or canned green beans once they're cooked.
Vitamin K per cup: 76 mcg
This is a hefty amount of the vitamin, so you might want to think twice about how much coleslaw and other cabbage-y recipes you pile on your plate.
Vitamin K per cup: 92.5 mcg raw, 139 mcg cooked
As you can see, cooking your veggies actually enriches the amount of vitamins. While that's normally a good thing, you want to be careful with it when it comes to vitamin K and blood thinners.
Vitamin K per cup: 222 mcg
The USDA listed this as the amount of vitamin K in a pan-cooked cup of the vegetable. If you prefer boiling Brussels sprouts, that will only give you about 140 mcg of the vitamin.
Vitamin K per cup: 389.6 mcg raw, 418.5 mcg cooked
This popular leafy green is clearly way above the recommended daily amount of vitamin K, which is usually fine. But if you're a big fan of kale and on a blood thinner, you should probably talk with your doctor about how much of it you can safely eat.
Vitamin K per cup: 145 mcg raw, 887 mcg cooked
The popular salad choice gets the heftiest boost in vitamin K from cooking the leaves — a little more than six times the amount while raw! Which means it's definitely worth keeping an eye out for and possibly avoiding any boiled or sautéed spinach.
Again, we want to stress how you don't need cut any of these foods out of your diet completely. This isn't an excuse to skip your veggies! However, if you're a big fan of any delicious green vegetable listed here and happen to be on a blood thinner, you should definitely talk with your doctor about how to make sure they don't cause any blood clots.