Vitamin K and potassium are often confused due to the chemical symbol of potassium being K+. Vitamin K is a vitamin, while potassium is a mineral. They have very different functions in the human body. Vitamin K and potassium are found together in some foods, but high vitamin K and high potassium foods usually differ.
Vitamin K Functions
Vitamin K is a fat soluble vitamin. It is absorbed into the body and metabolized similarly to fat. Vitamin K has several functions, but mainly as an enzyme required for the formation of prothrombin, which is used for blood clotting. Many people take anticoagulant medications, or blood thinners, to decrease their risks of stroke or deep vein thrombosis, which are caused by blood clots in circulation. When taking anticoagulants such as warfarin or coumadin, vitamin K in the diet can decrease the effectiveness of the medication. It is now recommended by health professionals to consume consistent amounts of vitamin K to maintain consistent clotting time in your blood.
Vitamin K Foods
Vitamin K is found mostly in green leafy vegetables. The average intake of vitamin K in adults is 70-80 mcg per day. The recommended intake for vitamin K, known as the percent daily value is 80 mcg. A high vitamin K food is more than 200 percent DV. If taking anticoagulants, avoid or limit foods from this group to one serving daily. These foods include cooked kale, spinach, turnip greens, collards, swiss chard, parsley, and mustard greens. Moderately high vitamin K foods are 60 to 199 percent of DV. These foods include Brussells sprouts, raw spinach, raw turnip greens, green leaf lettuce, broccoli, endive lettuce and romaine lettuce. All other foods not listed may be eaten in unlimited quantities. See you doctor, pharmacist or dietitian for more information.
(Important Drug and Food Information; Important information to know when you are taking: Coumadin and Vitamin K; Warren Grant Magnuson Clinical Center, National Institutes of Health Drug-Nutrient Interaction Task Force; December, 2003)
Potassium Functions
Potassium is a mineral and is the most abundant cation in intracellular fluid, or within cells. Potassium has two main functions. First, it works with sodium and chloride in the osmotic pressure and acid base balance in blood and cells. Potassium also works with other minerals in muscle contraction, particularly in cardiac, or heart muscle contraction. Many people have difficulty maintaining normal levels of potassium. If you are taking diuretics for fluid gain such as lasix or furosemide, your body loses K+ when you lose extra fluid through urine. In this case, high K+ foods or supplements can be consumed to maintain normal K+ levels in blood. Potassium can also be difficult to control with kidney disease, since this is one mineral regulated and excreted by the kidneys. When kidney function worsens or dialysis is required, potassium intake may need to be decreased to maintain normal blood potassium levels.
Potassium Foods
Potassium is highest in many fruits and vegetables including bananas, oranges, orange juice, raisins and other dried fruits, watermelon, peaches, prune juice, tomatoes, tomato juice, potatoes, sweet potatoes, spinach, winter squash and pumpkin. Milk and dairy products have higher levels of potassium and some salt substitutes as well. Lower potassium foods include apples, grapes, lemons, limes, cranberries, blueberries, blackberries, canned fruits, pears, cucumbers, lettuce, eggplant cauliflower, cabbage, carrots, okra and summer squash. For more information, see your dietitian.
References
- Modern Nutrition in Health and Disease, Eighth Edition; Maurice E. Shills, James A. Olson, and Moshe Shike; 1994
- Important Drug and Food Information; Important information to know when you are taking: Coumadin and Vitamin K; Warren Grant Magnuson Clinical Center, National Institutes of Health Drug-Nutrient Interaction Task Force; December, 2003
- Food Choices for Renal Patients , Jacksonville Dietetic Association, 2003
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