Potassium and chronic kidney disease

What is potassium and what does it do in the body?

Potassium is a mineral that controls nerve and muscle function. One very important muscle—the heart—beats at a normal rhythm because of potassium. In addition potassium is necessary for maintaining fluid and electrolyte balance and pH level.

In order for potassium to perform these functions, blood levels must be kept between 3.5 and 5.5 mEq/L. The kidneys help keep potassium at a normal level. Potassium levels that are too high or too low can be dangerous.

How will I know if my potassium is too low or high

Low potassium

Potassium comes from the foods we eat. Healthy kidneys remove excess potassium in the urine to help maintain normal levels in the blood.

Since most foods have potassium, low potassium (hypokalemia) is uncommon in people who eat a healthy diet. Poor food intake, excessive vomiting and diarrhea and taking certain medications, such as diuretics, can cause low potassium levels.

Some of the effects of low potassium (hypokalemia) include:

• muscle weakness
• cramping
• fatigue
• confusion
• problems with muscle coordination
• irregular heartbeat
• heart failure

Low potassium (hypokalemia) is rarely a problem for people with advanced kidney failure, because the kidney loses the ability to remove potassium. Blood tests are performed to help the doctor evaluate potassium levels.

High potassium

When kidneys fail they can no longer remove excess potassium, so the level builds up in the body. High potassium in the blood is called hyperkalemia. This may occur in people with advanced stages of chronic kidney disease (CKD).

Some of the effects of high potassium (hyperkalemia) are:

• nausea
• weakness
• numbness or tingling
• slow pulse
• irregular heartbeat
• heart failure
• sudden death

For people with stage 5 CKD (also known as end stage renal disease or ESRD), dialysis is necessary to help regulate potassium. Dialysis is very effective at removing excess potassium from the blood. Between dialysis treatments, however, potassium levels rise. Because of this, high potassium foods must be limited so potassium levels do not get too high before the next treatment.

High potassium (hyperkalemia) is likely to occur when dialysis treatments are skipped or shortened. Missed treatments allow potassium to build up to dangerous levels in the blood. This can lead to irregular heartbeats and even cause the heart to stop beating.

Know your potassium levels

Your potassium levels will be checked regularly. Ask your renal dietitian or doctor about your potassium results. Checking your potassium levels will guide your healthcare team to help keep your potassium in a safe range.

Laboratory ranges for CKD
Low range	less than 3.5 mEq/L
Safe range	3.5 - 5.5 mEq/L
Unsafe range	5.6 - 6.0 mEq/L
Dangerous	more than 6.0 mEq/L

If your potassium is too high, your doctor will determine the cause and adjust your dialysis treatment time, if necessary. Your renal dietitian will review your food intake and give you ways to lower potassium in your diet. Potassium requirements vary for each individual. Your dietitian will determine the right amount of potassium for you to have in your diet.

How to prevent potassium levels from getting too high

The following are things people with kidney failure can do to keep their potassium at safe levels:

• Talk to your renal dietitian about creating an eating plan with the right amount of potassium.
• Watch your diet. Limit foods that are high in potassium.
• Limit fruits and vegetables to the amounts recommended by your dietitian.
• Limit milk and milk products or replace with nondairy substitutes recommended by your dietitian.
• Discard liquids from canned fruits and vegetables.
• Avoid salt substitutes and other seasonings that contain potassium.
• Read labels on “low salt” or “low sodium” packaged foods to be sure potassium ingredients like potassium chloride are not added.
• Keep an eye on serving size. Almost all foods have some potassium, so even a low potassium food can turn into a high potassium food when eaten in large amounts.
• Do not skip dialysis. Stay on dialysis for the full treatment time. The full treatment time is necessary to clean the blood adequately.
• Leach high potassium vegetables, if including them in your diet. Leaching removes some of the potassium. Ask your renal dietitian which vegetables to leach and how much you can eat. (See instructions for leaching below.)
  • How to leach vegetables to lower potassium
    • Peel the vegetable, cut into small pieces and place in a very large pot of water.
    • Rinse the vegetables.
    • Fill the pot with water and let the vegetables soak for at least four hours at room temperature (or you can let them soak over night in the refrigerator).
    • After soaking, rinse the vegetables with clean water.
    • Cook vegetables as desired.
    • Limit portion to one serving, usually 1/2 cup.

What to eat and what to limit

The suggestions and lists below will help give you an idea of some high and low potassium foods. See your health care team for a complete guide based on your requirements.

To keep your potassium levels normal try these suggestions:

Food type	Tip
Fruit	Choose apples, berries or grapes, instead of bananas, oranges or kiwi. Select a small piece of watermelon, instead of cantaloupe or honeydew. Eat a peach, plum or pineapple, instead of nectarines, mangos or papaya. Choose dried cranberries, instead of raisins or other dried fruit. Drink apple, cranberry or grape juice, instead of orange juice or prune juice. Use lower potassium canned pears, peaches or fruit cocktail, instead of fresh fruit.
Vegetables	Choose green beans, wax beans or snow peas, instead of dried beans or peas. Prepare mashed potatoes or hash browns from leached potatoes, instead of eating baked potato or French fries. (Be sure to leach your potatoes to lower potassium content.) Use summer squashes like crookneck or zucchini, instead of winter squashes like acorn, banana or hubbard squash. Cook with onion, bell peppers, mushrooms or garlic, instead of tomatoes, tomato sauce or chili sauce. Drink ice water with sliced lemon and cucumber, instead of drinking vegetable juices.
Dairy	Use nondairy creamer or unenriched rice milk, instead of milk. Prepare pudding with nondairy creamer, instead of eating yogurt or pudding made with milk. Enjoy sherbet, sorbet or a Popsicle®, instead of ice cream or frozen yogurt.
Miscellaneous	Choose vanilla- or lemon-flavored desserts, instead of chocolate desserts. Eat unsalted popcorn or pretzels, rice cakes, jelly beans or hard candies, instead of nuts or seeds. Season with pepper, lemon or low sodium herb and spice blends, instead of salt substitutes.

High potassium foods

Be sure to limit or avoid high potassium foods.

Food type	High potassium foods
Fruits	Avocados Bananas Cantaloupe Dried fruits Honeydew	Kiwi Mangos Oranges & orange juice Papaya Prune juice
Vegetables	Artichoke Dried beans & peas Pumpkin Potatoes, French fries Spinach (cooked)	Sweet potatoes Tomatoes, tomato sauce Vegetable juices Winter squash
Dairy	Milk Yogurt	Ice cream
Miscellaneous	Chocolate Molasses	Salt substitute Seeds and nuts

Disclaimer: The above list does not include all foods high in potassium. Portion size also plays a role in the amount of potassium you get from the foods you eat. Consult your dietitian and doctor about what to eat based on your individual requirements.

Low potassium foods

Ask your dietitian about the amount you can safely eat. Portion size is important. Eating too much or too often can result in high potassium levels even when eating low potassium foods.

 

Food type	Low potassium foods
Fruits	Apples Berries Fruit Cocktail Grapes Lemon	Peaches Canned Pears Pineapple Plums Watermelon
Vegetables	Carrots Cabbage Cauliflower Cucumber Eggplant	Green beans Lettuce Onion Summer squash Sweet peppers
Dairy substitutes	Nondairy creamers Rice milk (unenriched)	Sorbet or Popsicle Nondairy whipped topping
Snacks	Jelly Beans Hard candies Plain donuts	Popcorn (unsalted) Pretzels (unsalted) Red licorice

Disclaimer:  The above list does not include all foods low in potassium. Portion size also plays a role in the amount of potassium you get from the foods you eat.  Consult your dietitian and doctor about what to eat based on your individual requirements.