Potassium deficiency
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Key facts
- Potassium is a mineral that is essential for all of the body's functions.
- It helps your nerves, muscles and heart function properly, and also helps move nutrients and waste around your cells.
- Potassium deficiency (hypokalaemia) is when a person has abnormally low levels of potassium in their body.
- Some people with potassium deficiency don't experience any symptoms, but others will notice muscle weakness, muscle cramps and an abnormal heart rhythm (arrhythmia).
- Potassium deficiency is treated with supplements, which you can take orally (for example, a tablet) or your doctor can arrange an intravenous potassium infusion — it's also important to treating the cause of the problem to prevent it recurring.
What is potassium?
Potassium is a mineral that is essential for all of the body's functions. It helps nerves, muscles and the heart to function properly, as well as helping move nutrients and waste around your cells.
What is potassium deficiency?
Potassium deficiency is when a person has abnormally low levels of potassium in their body. It is also called hypokalaemia.
What are the symptoms of potassium deficiency?
Some people with potassium deficiency don't experience any symptoms.
If you do have symptoms, they may include:
- weakness and fatigue
- feeling tired
- muscle cramps
- an abnormal heart rhythm (arrhythmia) — skipped heartbeats or an irregular heartbeat
What causes potassium deficiency?
There are many possible causes of potassium deficiency.
The amount of potassium in the body is affected by:
- the climate
- your level of physical activity
- using diuretic medicines ('water tablets')
- how much sodium you consume (as found in table salt)
You may be at risk of developing low potassium levels if you:
- become dehydrated, for example, with prolonged vomiting, diarrhoea or excessive sweating
- take certain medicines, such as diuretics, that increase the amount of potassium you lose via your urine
- have chronic kidney disease
- have certain endocrine (hormone) or metabolic problems
- have low magnesium levels
- don't get enough potassium from your diet (though this is very rare)
How is potassium deficiency diagnosed?
Potassium deficiency is diagnosed with a blood test. Your doctor may order a test as part of a routine medical examination, or because you have high blood pressure or kidney disease.
If you are found to have a potassium deficiency, your doctor will usually refer you for more tests to find out the cause.
How is potassium deficiency treated?
If you have low potassium, your doctor may recommend you take a supplement. You should only take a potassium supplement under medical supervision. Having too much potassium in the body can also cause serious health problems. If your levels are very low, you may need potassium through an intravenous drip in hospital.
Depending on the cause of your potassium deficiency, your doctor will also discuss with you any other treatments you need. They may also discuss ways to prevent the problem recurring.
If your medicines are causing the potassium deficiency, your doctor may suggest a change, or recommend you eat more foods that are high in potassium.
What are the complications of potassium deficiency?
Severe hypokalaemia can be life-threatening. The most serious complication is an irregular heartbeat (arrhythmia).
Can potassium deficiency be prevented?
Most people can prevent potassium deficiency by eating a healthy, balanced diet.
If you are at increased risk, for example if you are taking a diuretic medicine, talk to your doctor about your potassium levels.
Resources and support
- Visit Nutrition Australia for information about healthy eating.
- Eat for Health uses the Australian dietary guidelines to provide advice about the amount and types of food you need.
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Last reviewed: June 2023
