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Vitamin K Foods to Avoid While on Coumadin

author image Bonnie Crowe
Bonnie Crowe is a mother of two teenagers; a teacher and author of children's books, curriculum and articles on English grammar, literature, technology, art, parenting and career guides for high schoolers. She's a former director of AOL Parenting, a member of SCBWI, and a graduate from the University of California,Berkeley.
Vitamin K Foods to Avoid While on Coumadin
Coumadin is a blood thinner. Photo Credit pontific/iStock/Getty Images

Coumadin, the brand name for the prescription drug warfarin, is a blood thinner used to prevent dangerous blood clots that could cause a heart attack or stroke. Coumadin slows the rate that your blood forms clots. Vitamin K can counteract the Coumadin by making your blood clot faster, interfering with the drug’s effectiveness. If you are on blood thinners, you should eat consistent amounts of vitamin K in order to keep the medicine’s effectiveness consistent.

Watch Those Leafy Greens

Vitamin K Foods to Avoid While on Coumadin
Boiled spinach. Photo Credit milla1974/iStock/Getty Images

Leafy greens have both high vitamin K options and low vitamin K options. One-half cup of cooked kale has 531 micrograms of vitamin K. One-half cup of cooked spinach has 444 micrograms of vitamin K. Collard greens, Swiss chard and mustard greens all have between 279 micrograms and 418 micrograms per 1/2 cup cooked serving. One cup of raw turnip greens has 138 micrograms, 1 cup of raw spinach has 145 micrograms, green leaf lettuce has 71 micrograms per cup and romaine lettuce has 57 micrograms per cup. One cup of raw endive has 116 micrograms of vitamin K.

Broccoli, Brussels Sprouts and Green Veggies

Vitamin K Foods to Avoid While on Coumadin
Steamed brussel sprouts. Photo Credit Medioimages/Photodisc/Photodisc/Getty Images

One cup of cooked broccoli has 220 micrograms of vitamin K, while a cup of raw broccoli has 89 micrograms of the vitamin. Cooked Brussels sprouts have 219 micrograms of vitamin K per cup, and cooked cabbage has 82 micrograms per 1/2 cup. Four spears of asparagus has 48 micrograms of vitamin K. According to the University of Michigan Health System, the greener the plant, the higher the amount of vitamin K it has.

Green Teas, Herbal Teas and Supplements

Vitamin K Foods to Avoid While on Coumadin
Green tea. Photo Credit moodboard/moodboard/Getty Images

Make sure your doctor knows of any herbal teas, green teas or supplements you are taking. Green tea and certain herbal teas are rich in vitamin K. These could radically increase your vitamin K level and throw off the effectiveness of Coumadin in your body.

Be Consistent

Vitamin K Foods to Avoid While on Coumadin
Keep in contact with your doctor. Photo Credit Thomas Northcut/Digital Vision/Getty Images

According to the National Institute of Health, it’s imperative that people who are taking Coumadin keep the level of vitamin K in their bloodstream consistent. Sudden swings in the amount of vitamin K, either an increase or decrease, will affect your clotting factors so that your blood clots too quickly or not quickly enough. For this reason, you should carefully monitor how much vitamin K is in the foods you eat and eat the same amount of these foods every day. If you do alter your vitamin K intake, let your doctor know immediately.

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