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What are the ranges of mcg of vitamin K for low, medium, and high classifications?
There are no official guidelines for classifying foods as low, medium, or high, so when creating our lists for Vitamin K content we reviewed many sources. We looked at the recommended daily allowance (RDA) of Vitamin K (about 80 micrograms per day) as well as a grouping of ingredients by amounts.
We know that consuming an erratic diet of foods that are high and low in Vitamin K, with daily variations in the amount of Vitamin K in the diet, can cause wide swings in the bioavailability of warfarin. Consequently, we wanted folks using these lists to have more awareness of those ingredients that were high in Vitamin K more than those that contained a medium or low amount. Here's the result:
Low < 20 micrograms (mcg) per serving
Medium > 20 mcg but < 40 mcg
High > 40 mcg
We label our recipes as being "safe for Coumadin users" if the meal contains less than 40 mcg for a main course or complete meal. If the side dish contains less than 20 mcg, we consider that as being safe. Instead of avoiding all Vitamin K intake, our approach is to recommend a diet in which you consume about the same amount of Vitamin K each day, and our book, The Dr. Gourmet Diet Plan for Coumadin Users, is geared toward this.
Thanks for writing,
Timothy S. Harlan, MD, FACP, CCMS