Broccoli wars: vitamin K and blood-thinners

Q. I take a blood-thinner (Coumadin) and my doctor gave me a list of foods to avoid because they cause an interaction with the medication. The list includes broccoli, cabbage, brussels sprouts, kale, and spinach. Aren't these foods supposed to be super good for you?  What will I be missing if I stop eating these foods?

A. The list that your doctor gave you contains foods that are high in Vitamin K, a nutrient that plays a key role in the formation of blood clots. The clotting mechanism isn't necessarily a bad thing, by the way. It's what keeps you from bleeding to death from a paper cut. But if your blood forms clots too easily, you can have a stroke or heart attack.  Vitamin K does a lot of other important things for you, too. It helps protect against both heart disease and osteoporosis by regulating the way your body stores and uses calcium, for example.

Coumadin (AKA Warfarin) prevents blood clots by blocking the action of vitamin K--and that's why your doctor wants you to avoid foods that are high in vitamin K.  Consuming too much vitamin K will essentially undo the effects of the medication. But you're absolutely right that these foods are some of the healthiest foods you can eat. In addition to vitamin K, foods like broccoli and kale contain important cancer-fighting compounds along with lots of fiber, vitamin A, and other good stuff.

There is a way for you to get all the health benefits of these foods without infering with your blood-thinning therapy--but you'll need to work with your doctor.

With blood-thinners, it's critical to get the dosage right. Too much medication and you are at risk of uncontrolled bleeding; too little, and you are at risk of a blood clot. Your doctor calibrates your dosage with a blood test that measures how long it takes for your blood to form a clot. 

The amount of medication it takes to get the right clotting time is directly tied to how much vitamin K is in your diet.  If you eat 4 servings of broccoli one day and none the next, it's going to very hard to find the right dosage of medication for you. The easiest way for your doctor to make sure that you get about the same amount of vitamin K every day is to have you avoid foods that contain a lot of it.  But then--as you've pointed out--you're not getting the benefits of these great foods.

With a little effort, you can have the best of both worlds

Getting all the health benefits of broccoli and other vitamin K-rich foods without messing up your medicine will take a little effort from both you and your doctor--and you'll absolutely have to work together. But I think it's well worth it!

Once you've cleared it with your doctor (don't skip this step!), your job will be to be sure that you get about the same amount of vitamin K from your diet every day.  You can generate a list of foods that are high in vitamin K with the ND nutrient search tool.  You can also use ND's pantry tool to keep track of your totals automatically. Don't worry about small variations from day to day--it's the big picture we're worried about here. The easiest thing might be to plan to eat one serving (but only one) of a vitamin K-rich vegetable every day. 

Meanwhile, your doctor's job will be to test your blood-clotting time and adjust your blood-thinning medication (if needed) to accomodate the amount of vitamin K in your diet.  Here's another good article on working with your doctor to navigate through the necessary adjustments.

Once you've gotten the go-ahead from your doctor, here's one of my favorite broccoli recipes. Also, be sure to check out the Cooking Healthy recipe collection on Epicurious.com for more great ways to enjoy these super healthy foods.