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Anticoagulants (Blood Thinners) and Vitamin K

What is an anticoagulant?

An anticoagulant is a blood thinner, which helps keep blood clots from forming or getting bigger. It can be used to prevent blood clots in the veins and arteries that can lead to heart attacks and strokes.

The amount of anticoagulant needed to manage certain health conditions varies from person to person. Your child will have regular blood tests to make sure they are getting the right amount of medicine.

Vitamin K and anticoagulant medicines

Vitamin K in the diet can react with an anticoagulant and how it works in the body. The amount of vitamin K your child eats may affect the dose of medicine ordered by the doctor. The medicine dose is balanced with the amount of vitamin K in the diet. This balance will give the best result.

Vitamin K is found mostly in green vegetables and some fruits. Green leafy vegetables such as collards, spinach, broccoli, Brussels sprouts, and cabbage contain vitamin K. Some fruits such as kiwi, blackberries, and blueberries are also rich in vitamin K.

Keep a consistent diet

Your child does not need to avoid vitamin K foods. You just need to make sure there are no big changes in the amount of vitamin K in your child’s diet.

If your child likes certain foods that are high in Vitamin K, the amount eaten should be consistent each week. For example, your child could eat ½ cup of a vitamin K food three times per week, every week while on anticoagulant.

Talk to your care team before taking any new or different dietary supplements, vitamins, minerals, or herbs. Nutritional supplements like Ensure® or Boost® contain vitamin K. Ask the medical team before starting any liquid meal replacement drink.

Call the medical team right away if your child is unable to eat for several days or has an upset stomach, diarrhea, or fever. Not eating will decrease the amount of vitamin K in the body and could affect how the anticoagulant works.

Vitamin K in food

Use this list of foods to make sure there are no big changes in the amount of vitamin K your child eats.

HIGH vitamin K foods (more than 100 micrograms)

Food Vitamin K (micrograms per serving)
Collard greens, cooked 1060 (1 cup)
Kale, cooked 1054 (1 cup)
Spinach, cooked 884 (1 cup)
Turnip greens, cooked 526 (1 cup)
Brussels sprouts, cooked 220 (1 cup)
Broccoli, cooked 220 (1 cup)
Cabbage, cooked 163 (1 cup)
Spinach, raw 145 (1 cup)
Asparagus, cooked 144 (1 cup)
Vegetables high in Vitamin K

Many green leafy vegetables are HIGH in Vitamin K

MEDIUM vitamin K foods (between 10 and 100 micrograms)

Food Vitamin K (micrograms per serving)
Broccoli, raw 89 (1 cup)
Coleslaw 89 (1 cup)
Okra, boiled, cooked 64 (1 cup)
Romaine lettuce 63 (1 cup)
Cashews 45 (1 cup)
Avocado 42 (1 cup)
Peas 41 (1 cup)
Kiwi 31 (1 medium)
Blackberries 29 (1 cup)
Blueberries 28 (1 cup)
Grapes 23 (1 cup)
Pistachios 17 (1 cup)
Carrots, raw 15 (1 cup)
Iceberg lettuce 13 (1 cup)
Mayonnaise 12 (2 tbsp)

LOW vitamin K foods (below 10 micrograms)

Food Vitamin K (micrograms per serving)
Cucumber 9 (1 cup)
Zucchini 9 (1 cup)
Olive oil 8 (1 tbsp.)
Pear 7 (1 cup)
Beans (plain, black, white) <6 (1 cup)
Cantaloupe 4 (1 cup)
Apple 3 (1 cup)
Pecans 3 (1 cup)
Strawberries 3 (1 cup)
Dairy (milk, ice cream, yogurt, cheese) <3 (1 cup)
Potato with peel, baked 2 (1 cup)
Eggs 1 (1 egg)
Grains (bread, pasta, oatmeal) 1 (1 cup)
Citrus fruits (orange, lemon, lime, grapefruit) <1 (1 cup)
Rice (brown, white, wild) <1 (1 cup)
Peanuts <1 (1 cup)
Beverages (water, black tea, green tea, orange juice) <1 (1 cup)

If you have questions about anticoagulants and vitamin K, talk to your doctor, nurse, pharmacist, or dietitian.

Key Points

  • An anticoagulant is a blood thinner used to help prevent or treat blood clots.
  • Vitamin K in the diet can interact with anticoagulant medicines.
  • Vitamin K is found in green vegetables and some fruits.
  • For anticoagulants to work properly, keep a consistent amount of vitamin K in your child’s diet.
  • Contact your medical team if your child is unable to eat or has nausea, vomiting, or diarrhea.

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Reviewed: August 2022