Bowl of leafy greens including kale and spinach

What is potassium?

Learn all about potassium, an essential mineral required for electrolyte and water balance. Find out why we need it and which foods are rich sources of potassium.

Potassium is an essential mineral that is needed in the body for electrolyte and water balance, in addition to the daily functioning of cells. Certain types of cooking, such as boiling, can destroy the potassium in some foods so it is often better to steam, bake or stir-fry vegetables. In addition, food processing reduces the amount of potassium in many foods and a diet high in processed foods and low in fresh fruits and vegetables is often lacking in potassium.


Always speak to your GP or healthcare provider before taking a new supplement or if you are concerned about nutritional deficiencies.

Why do we need potassium?

Potassium plays a role in maintaining normal blood pressure and is involved in muscle contraction. It may also reduce the risk of recurring kidney stones. Evidence shows that increasing potassium intake significantly reduces blood pressure in adults.

Tomatoes in a colander

How much potassium do we need and what are the effects of consuming too much?

Daily UK recommendations for potassium in healthy individuals are 3500mg for men and women. It is difficult to exceed this through diet alone in healthy individuals as it is excreted by the kidneys. For those taking potassium supplements, it may be possible to have too much and possible side effects would include nausea, diarrhoea and stomach pain.

Which foods are good sources of potassium?

Potassium is found in a wide range of foods, especially fruits and vegetables such as leafy greens, tomatoes, cucumbers, courgette, aubergine, pumpkins, potatoes, carrots and beans. It’s also found in dairy foods, meat, poultry, fish, pecan and walnuts.

Recipes rich in potassium

Squash & spinach fusilli with pecans
Kale & apple soup with walnuts
Courgette, pea & pesto soup
Maple pecan beans

More on vitamins and minerals

Five nutrients every woman needs
Vital vitamins
What is vitamin B12?
The best sources of vitamin C
Am I getting enough vitamin D?

This article was published on 18th June 2019.

Emer Delaney BSc (Hons), RD has an honours degree in Human Nutrition and Dietetics from the University of Ulster. She has worked as a dietitian in some of London’s top teaching hospitals and is currently based in Chelsea.


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