Coumadin & Shellfish Effects

Coumadin is a common medication used to reduce blood clots. It's an important medication for individuals who are at risk for heart attack or stroke. Maintaining a healthy diet while taking Coumadin is very important, as vitamin K-laden foods have the potential to decrease the effects of the medication.

What Is Coumadin?

• Coumadin is a medically prescribed anticoagulant (blood thinner). Its purpose is to reduce the formation of blood clots. By blocking the synthesis of certain clotting factors, blood clots cannot form. Coumadin is normally prescribed to individuals who are at an increased risk for stroke, heart attack, and blood clots in the arteries and veins.

Precautions

• Individuals taking Coumadin will not form blood clots as quickly as other individuals. It's important not to take any aspirin, acetaminophen or NSAIDs (non-steroidal anti-inflammatory drugs), because they can affect bleeding and actually cause increased bleeding, particularly in the stomach and intestines.

  Coumadin is not for individuals with a bleeding disorder, blood cell disorder, stomach ulcers or stomach bleeding, or heart infection, or a history of aneurysm, blood clot or bleeding in the brain.

Food and Drink to Avoid

• In addition to not using certain medications, individuals taking Coumadin should avoid cranberries, cranberry juice and cranberry-containing herbal products. Alcohol should also be avoided, because it can increase some of Coumadin's side effects.

  It is also important to avoid foods that are high in vitamin K, as vitamin K is known to decrease the effects of Coumadin.

Coumadin and Vitamin K

• Vitamin K plays an essential role in assisting the liver in clotting. Coumadin works by blocking the clotting. An increased amount of vitamin K can interfere with Coumadin's blood-clotting effects, so individuals taking the medication must maintain a consistent amount of vitamin K and not drastically increase or decrease the amount in their daily diet.

  The FDA recommends that individuals on a daily 2,000 calorie diet have a daily intake of 80 micrograms of vitamin K. Your daily intake of vitamin K should not fluctuate greatly in either direction. You can speak to your physician about vitamin K foods that you enjoy, and he can use that information to aid in determining an appropriate dose of Coumadin.

What Foods Are High in Vitamin K?

• Foods to be avoided include green leafy vegetables such as spinach, cabbage and collards. Broccoli, brussel sprouts, liver, Swiss chard, many types of finned fish and other foods that contain large amounts of vitamin K should not be eaten.

  Coumadin's website features a chart that lists common foods and drinks and their portion sizes and the amount of vitamin K that is in each portion. You can use this list to guide you in maintaining a consistent amount of vitamin K.

What about Shellfish?

• Shellfish is a broad seafood term that includes crustaceans (creatures with elongated bodies and crust-like shells) and mollusks (soft-bodied invertebrates that are covered by 1- or 2-piece shells). Foods that are classified as shellfish include lobsters, crabs, shrimp, crayfish, prawns, limpets, snails, whelks, scallops, clams, oysters and mussels.

  Some shellfish products are fairly low in vitamin K. According to the chart on Coumadin's website, shrimp has virtually no vitamin K. And according to Vital Health Zone, lobster, crabs, crayfish and prawns also have little to no vitamin K. Scallops, clams and oysters also have minimal amounts of vitamin K.