Dr. Danny Lee’s Blog

For people on the blood thinner Coumadin (generic: warfarin) it can be confusing to know what foods will affect your levels. First, we should cover what is Coumadin (warfarin)? Coumadin is a medication that deprives the liver of vitamin K. Coumadin (warfarin) is a very slow acting medication. It takes up to 48 hours to see any change is your coagulation. Which is why when your physician changes your couamdin dose he or she will ask you to check your blood test again no earlier than 2 days from the time you changed the dose. If you are taking alternating doses, you might not be asked to repeat a test (INR) for a week.

We measure the effectiveness of the warfarin through a blood test called Protime or PT for short. Since different labs use differing methods of measuring protime, a standarize ratio was created called the INR which stands for INternational Ratio. This was we can measure the effective thinness of a persons blood no matter where they had it drawn. For people with blood clots, stroke, or irregular heart rhythms, the INR will needs to maintained between 2-3. For people with articifical heart valves, the INR is kept from 2.5-3.5. So when your doctor or nurse is calling to report your blood tests they will often quote an INR value and knowing what range your warfarin dose should be kept is helpful.

Vitamin K is important in the synthesis of some coagulation factors made by the liver. WIthout these factors, the blood ability to coagulate is impaired and therefore thinned. Now in truth people get a small amount of Vitamin K from the bacteria in their bowel, but the main source is from their diet. In addition, vitamin K is a fat soluble vitamin so we can store it in our fatty tissue.

So where do we find vitamin K? The typically associated with high levels of vitamin K are cabbage, cauliflower, spinach and other green leafy vegetables (e.g. kale, lettuce, swiss chard, endives, brussel sprouts, mustard greens, turnip greens, spinach, collard greens), asparagus, broccoli, scallions, pistachio nuts, sauerkraut, parsley and soybeans.