Potassium is essential for kidney function. Too much or too little potassium can affect this function and lead to complications.

Potassium plays a key role in a number of bodily processes, including nerve transmission, heart contractility, cellular transport, and normal kidney function. It is important that people get sufficient potassium from the diet, as an imbalance can cause problems in the body.

In this article, we look at the association between potassium and kidney health. We also explain how people with chronic kidney disease (CKD) can manage their dietary needs for better health.

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The kidneys are bean-shaped organs that remove waste from the blood and help maintain a healthy balance of water, salts, and minerals. CKD impairs kidney function, reducing the kidneys’ ability to carry out these processes.

Healthy, functioning kidneys excrete the majority of dietary potassium a person takes in. Disturbances to this process can cause either too much, or too little potassium to exit the blood. Due to this, people living with CKD have an increased risk of potassium imbalance.

The National Institutes of Health (NIH) states that the standard amount of potassium in the blood typically ranges from 3.6 to 5.0 millimoles per literTrusted Source (mmol/L).

In people with CKD, the improperly functioning kidneys lose the ability to filter fluids and electrolytes in the body, which can lead to dangerously high levels of potassium in the blood. Hyperkalemia is the medical term for excessively high potassium levels.

A doctor can diagnose hyperkalemia with a blood test, and they may also order an electrocardiogram to make sure that the heart is working properly.

Hyperkalemia may not produce symptoms for some people. However, potassium levels of 6 milliequivalents per liter or higher can be life threatening. This can cause severe symptoms, including:

Other possible causes of hyperkalemia besides CKD include diabetes, trauma, rhabdomyolysis, medication use, and excessive potassium intake.

To treat hyperkalemia, a doctor may recommend eating a diet with lower potassium levels or changing medications. In cases of severe hyperkalemia, they might prescribe medication to treat it.

Just as potassium levels in the body can get too high, they can also drop too low, which doctors call hypokalemia. Hypokalemia is typically due to another underlying medical illness that a doctor must diagnose.

Possible causes of hypokalemia includeTrusted Source:

Symptoms of hypokalemia may include:

A doctor can diagnose hypokalemia using blood and urine tests. They will treat it by addressing the underlying cause, as well as replenishing potassium and fluids.

For adults, The NIH suggests a daily intakeTrusted Source of 2,600 mg for females and 3,400 mg for males.

Doctors may recommend a potassium-restricted diet of roughly 2,000 mg per day for people with moderate-to-severe CKD. A dietitian can advise on the specific level of restriction. People with CKD may wish to consider avoiding or limiting the consumption of high-potassium foods.

Other ways to manageTrusted Source dietary potassium include:

  • draining and rinsing food
  • replacing salt and salt substitutes with other seasonings
  • reading all food labels carefully

When dining out, people can take steps to avoid eating too much potassium. For instance, they can choose restaurants with suitable options on the menus and even call ahead to request special dietary alterations to their preferred meal option. They can also pay close attention to their diet throughout the rest of the day.

Some examples of low-potassium foods include:

  • apples, pineapples, grapes, strawberries, and cranberries
  • cauliflower, lettuce, onions, peppers, and radishes
  • pita, tortillas, white bread, and white rice
  • egg
  • tofu

High-potassium foods include:

  • bananas, melons, oranges, raisins, prunes, and avocado
  • bran products and granola
  • beans
  • artichokes, spinach, tomatoes, plantains, and winter squash
  • brown rice and potatoes

Some individuals with CKD may find it challenging to plan meals because so many foods have high levels of potassium. However, there is a method called leaching that can lower the amount of potassium in some foods.

People can leach vegetables by cutting them and soaking them for a few hours in warm, unsalted water. They can then drain the water and wash the vegetables using warm water. If they wish to cook the vegetables, they should use unsalted water.

If a person with CKD does decide to consume a meal high in potassium, it is important to try to cut down on the serving size.

Limiting potassium intake helps people with CKD lower their risk of worsening disease.

A person with CKD may be less tolerant of high sodium levels in their body. A high sodium diet can cause a large amount of fluid in the body, which can result in symptoms of swelling or shortness of breath. Doctors typically use drugs called diuretics to treat these symptoms.

People with CKD also tend to retain more hydrogen in their body.

Hydrogen ions act as acids in the body. If the kidneys are not working properly, the body will have higher levels of hydrogen ions. Doctors refer to this as metabolic acidosis. Individuals with metabolic acidosis may require bicarbonate supplements.

The inability of the kidneys to filter blood effectively can result in higher levels of phosphate and lower levels of calcium. This imbalance can cause bone weakness and increase the risk of heart disease and stroke.

Chronic kidney disease makes it difficult for the kidneys to function properly, which can cause problems with the levels of nutrients, such as potassium, in the body. An imbalance of potassium in the body can cause complications relating to the muscles and the heart.

People with CKD need to have regular checkups with their doctor and a dietitian to manage their potassium levels and appropriately take care of their health.