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Tree fruits such as bananas, are rich in potassium.

Tree fruits such as bananas, are rich in potassium.
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3-minute read

What is potassium?

Potassium is a mineral and electrolyte, meaning it conducts electricity. It is essential for all of the body’s functions. It helps nerves, muscles and the heart to function properly, as well as moving nutrients and waste around cells.

What does potassium do?

Potassium is essential for life. It allows the nerves to respond to stimulation and muscles to contract (tighten), including those in the heart. It also offsets the effect of sodium (present in table salt) in raising blood pressure, and moves nutrients into cells and waste products out of cells.

The potential health benefits of potassium include:

  • reducing blood pressure
  • protecting against strokes
  • protecting against osteoporosis
  • preventing kidney stones
  • reducing water retention

The kidneys control potassium levels in the body and remove excess potassium in urine. If the kidneys do not work properly, potassium may build up in the blood. This can be a very dangerous condition because it may cause the heart to beat irregularly or stop beating.

Can I have too much or too little potassium?

The amount of potassium in the body can be affected by the climate, physical activity, using diuretics, and consuming sodium (salt).

An imbalance of potassium can lead to health problems:

Low potassium

Low potassium (hypokalaemia) can lead to symptoms including weakness, tiredness, muscle cramps, constipation and abnormal heart rhythms.

Hypokalaemia can happen if you become dehydrated, for example due to vomiting or diarrhoea, or from sweating excessively. Diuretics (fluid tablets) can also cause low potassium. Sometimes, people may have low potassium because they are not eating enough foods high in potassium.

High potassium

A high potassium (hyperkalaemia) is a serious and potentially life-threatening condition. It is usually discovered through blood tests ordered to explain or monitor another condition.

If you have unusually high levels of potassium, you can feel weak and tired, feel nauseous and have an abnormal heart rhythm.

Hyperkalaemia can be caused by kidney disease or taking medications that decrease the amount of potassium the body removes in the urine.

If you have these symptoms and believe your potassium levels might be high, contact your doctor immediately. They can check your potassium levels with a blood test.

How much potassium do I need?

How much potassium you need depends on your age and stage of life:

Stage of life Adequate intake for potassium (milligrams per day)
0-6 months 400 mg/day
7-12 months 700 mg/day
1-3 years 2,000 mg/day
4-8 years 2,300 mg/day
Adult men 3,800 mg/day
Adult women 2,800 mg/day
During pregnancy 2,800 mg/day
While breastfeeding 3,200 mg/day

Source: NHMRC

Because having too much potassium can affect your health, only take a potassium supplement under medical supervision. Babies under 12 months can get all the potassium they need from breast milk, formula and food.

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: April 2021

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