Potassium

Diet and nutrition Vitamins, nutrients, minerals, and supplements Potassium

Last Updated: February 01, 2023

Medically reviewed by NKF Patient Education Team

Potassium is vital for body functions, but imbalances can be harmful, especially with kidney disease. High or low levels may cause symptoms like muscle weakness or heart issues.

Table of Contents

About Potassium 

Potassium is an important mineral found throughout the body. Potassium is needed for many of the body’s functions including conducting electricity through the body (also known as an electrolyte). This electricity is needed to keep the heart beating regularly and the muscles working properly.

Your kidneys help keep the right amount of potassium in the body. Hyperkalemia is the term for when the potassium levels in the blood are too high. Hypokalemia is the term for when the levels are too low. Both situations can cause health problems. In kidney disease, the body has trouble removing extra potassium from the blood. This can cause potassium levels to rise and lead to serious health problems. People with kidney disease are also at risk for low potassium, especially during earlier stages of kidney disease.

Hyperkalemia is the term for when the potassium levels in the blood are too high. Hypokalemia is the term for when the levels are too low.

Causes of Imbalance 

Causes of HIGH Potassium (Hyperkalemia)

Causes of LOW Potassium (Hypokalemia)

  • Chronic kidney disease
  • High-potassium diet, especially in people who also have advanced chronic kidney disease 
  • Some medications, including certain types of antibiotics, antifungals, and blood pressure medications
  • Potassium supplements, including salt substitutes or over-the-counter supplements and herbal remedies 
  • Addison’s disease, a rare condition where your body does not make enough aldosterone (a hormone that helps manage potassium levels)
  • Burns or other severe injuries
  • Extremely high blood sugar levels 
  • Chronic kidney disease
  • Some medications, such as diuretics (water pills) and some antibiotics
  • Frequent diarrhea or vomiting
  • Eating disorders, such as bulimia
  • Adrenal gland disorders, such as hyperaldosteronism (high aldosterone levels) or Cushing’s syndrome
  • Laxative overuse, which can cause diarrhea
  • Low magnesium levels
  • Excessive sweating
  • Alcohol use disorder
  • Rare genetic disorders, such as Bartter syndrome or Gitelman syndrome

 

How potassium affects kidney patients

from NKF Hot Topics in Kidney Health

Signs and Symptoms 

Signs and Symptoms of HIGH Potassium (Hyperkalemia)

Signs and Symptoms of LOW Potassium (Hypokalemia)

Hyperkalemia does not usually cause symptoms. 

Hypokalemia does not usually cause symptoms, especially if it is a small decrease in the potassium level. 

If symptoms do appear, they may develop slowly over many weeks or months and are usually mild and non-specific, including:

  • Muscle weakness
  • Numbness
  • Tingling
  • Nausea or vomiting
  • Heart palpitations

If symptoms do appear, they may develop slowly over many weeks or months and are usually mild and non-specific, including:

  • Constipation
  • Feeling skipped heart beats or palpitations
  • Extreme tiredness or fatigue
  • Muscle weakness and spasms
  • Tingling or numbness

Symptoms are more common if the hyperkalemia comes on suddenly and causes very high levels of potassium. In this case, you may experience:

  • Heart palpitations
  • Arrhythmia (irregular heart rhythm) 
  • Shortness of breath
  • Chest pain
  • Heart attack
  • Nausea or vomiting

Symptoms are more common If the hypokalemia comes on suddenly and causes very low levels of potassium. In this case, you may experience:

  • Abnormal heart rhythms, especially in people with pre-existing heart disease
  • Muscle twitches
  • Muscle cramps
  • Low blood pressure
  • Lightheadedness or faintness

Sudden or severe hyperkalemia and hypokalemia are both life-threatening conditions that require immediate medical care. If you have symptoms of either, call 911 or go to the emergency room.

Sudden or severe hyperkalemia and hypokalemia are both life-threatening conditions that require immediate medical care. If you have symptoms of either, call 911 or go to the emergency room.

Tests

A simple blood test is used to measure the level of potassium in your blood. If you are at risk of high or low potassium, be sure you ask your healthcare provider about checking your potassium level.

Results 

  • Higher than 6.0: You are in the DANGER zone for very high potassium (severe hyperkalemia)
  • 5.1 to 6.0: You are in the CAUTION zone for high potassium (hyperkalemia)
  • 3.5 to 5.0: You are in the SAFE zone
  • 2.5 to 3.4: You are in the CAUTION zone for low potassium (hypokalemia)
  • Less than 2.5: You are in the DANGER zone for very low potassium (severe hypokalemia)

Treatment 

To develop a treatment plan, your healthcare provider will likely ask about your medical history, your diet, and the medicines you take (including over-the-counter products, herbal remedies, and supplements). Your healthcare provider may recommend one or more of the following strategies.

High Potassium (Hyperkalemia)

Limit foods that are high in potassium

Ask your healthcare provider or dietitian how much potassium is right for you. Your renal dietitian can also help you plan your diet, so you are getting the right amount of potassium. Eating too much can be harmful but eating too little can cause problems too. The Potassium in Your Diet AtoZ page can help you identify foods that are high in potassium and how to switch to lower potassium choices.

Avoid salt substitutes

These are often high in potassium. Most people with kidney disease should not use them.

Add a medication to help your body avoid holding on to extra potassium.

This medication may come from one or both of the following medication categories:
  • Water pills (diuretics)– these help your body get rid of extra potassium. They work by increasing the amount of potassium your body removes in the urine.
  • Potassium binders – these help lower the amount of potassium your body absorbs from food. These often come in the form of a powder. They need to be mixed with a small amount of water and taken with food. When swallowed, they “bind” to the extra potassium in your intestine and help to remove it. You must follow the instructions carefully when taking potassium binders. For example, potassium binders may interfere with how other drugs work if you take them at the same time. Potassium binders have not yet been approved for use in children.

Adjust or remove any medications that may be contributing to your high potassium levels.

Depending on what that medication is being used for and how high it raised your potassium level. This could either be a temporary change or you may be advised to avoid that medication permanently.

Adjust your dialysis settings to help remove some of the extra potassium during a session

This approach is only beneficial if you are already on dialysis, especially hemodialysis.

Low Potassium (Hypokalemia)

Eat more foods that are high in potassium or more servings of low-potassium foods.

The most common way to treat low potassium is to increase the amount of potassium you are already getting each day. The Potassium in Your Diet AtoZ page can help you identify some of the most common foods that are high in potassium and which ones have less.

Add a prescription potassium supplement

This is usually in the form of tablets to be taken by mouth. However, if your potassium needs to be increased quickly, potassium may be given through your vein (Intravenous or IV)

Adjust or remove any medications that may be contributing to your low potassium levels.

Depending on what that medication is being used for and how low your potassium level is, this could either be a temporary change or you may be advised to avoid that medication permanently.

Adjust your dialysis settings to help remove less potassium during a session

This approach is only beneficial if you are already on dialysis, especially hemodialysis.

Follow your treatment plan carefully, especially if you have diabetes, kidney disease, heart disease, or other chronic conditions. Following your treatment plan can help you keep your potassium levels in the goal range. If you are on dialysis, be sure to get all the treatments or exchanges prescribed to you.

Questions to Ask  

  • What was my most recent potassium level?
  • What is my goal potassium level?
  • Do any of my medications, supplements, or herbal remedies increase my risk for high or low potassium levels?
  • Which of my favorite foods are high in potassium? Which ones are low in potassium?

Resources 

NKF Council on Renal Nutrition CKD Kidney Dietitian Directory 
https://www.kidney.org/ckdrd

NKF Your Guide to Potassium  
Download the Potassium guide

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This content is provided for informational use only and is not intended as medical advice or as a substitute for the medical advice of a healthcare professional.
© 2024 National Kidney Foundation, Inc.