Patient education: Low-potassium diet (The Basics)

What is potassium? — Potassium is a mineral found in most foods. The body needs potassium to work normally. It keeps the heart beating and helps the nerves and muscles work. But people need only a certain amount of potassium. Too much or too little potassium in the body can cause problems.

Having too much potassium in the blood is called "hyperkalemia." This can cause heart rhythm problems and muscle weakness.

Who might need to be on a low-potassium diet? — People usually need to be on a low-potassium diet to treat or prevent hyperkalemia.

The most common causes of hyperkalemia are:

●Certain medicines – Some medicines, including certain ones for high blood pressure and heart problems, might raise the level of potassium in the body.

●Kidney disease – Normally, the kidneys filter the blood and remove excess salt and water through urination (figure 1). They keep the level of potassium in the blood normal. When the kidneys don't work well or stop working, they can't get rid of the potassium in the urine. Then, too much potassium builds up in the blood.

Many people who get a treatment called "dialysis" for kidney disease need to be on a low-potassium diet. Dialysis is a treatment that takes over the job of the kidneys.

What does eating a low-potassium diet involve? — Almost all foods have potassium. So the key is to:

●Choose foods with low levels of potassium (table 1)

●Avoid or eat only small amounts of foods with high levels of potassium (table 2)

Your doctor will probably recommend that you work with a dietitian (food expert) to help plan your meals. They will tell you how much potassium you should eat each day.

To figure out how much potassium you are eating, you will need to look at the food's nutrition label (figure 2). You will need to look at the:

●"Potassium" number – This tells you how much potassium is in 1 serving of the food. If you eat 1 serving, then you are eating this amount of potassium.

●"Serving size" – This tells you how big a serving is. If you eat 2 servings, then you are eating 2 times the amount of potassium listed.

What are other ways to cut down on potassium? — Here are some other ways to cut down on potassium:

●Drain the liquid from canned fruits, vegetables, or meats before eating.

●If you eat foods that have a lot of potassium, eat only small portions.

●Reduce the amount of potassium in the vegetables you eat. You can do this for both frozen and raw vegetables. (If the vegetables are raw, peel and cut them up first.) To reduce the amount of potassium, soak the vegetables in warm unsalted water for at least 2 hours. Then drain the water and rinse the vegetables in warm water. If you cook the vegetables, cook them in unsalted water.

More on this topic

Patient education: Dialysis and diet (The Basics)
Patient education: Chronic kidney disease (The Basics)
Patient education: Hyperkalemia (The Basics)

Patient education: Low-potassium diet (Beyond the Basics)
Patient education: Chronic kidney disease (Beyond the Basics)