What is potassium and why do we need it? The understanding nutrients series

We’re back with another edition of the understanding nutrients series! I started this series to give you an idea about the different nutrients our bodies need and what they do. Potassium is the first mineral I’ll be doing.

What is a mineral?

I’m sure you’ve heard the term ‘vitamins and minerals’ but you’re probably wondering what a mineral is. Minerals are a micronutrient – this means a nutrient that we need them in small amounts. Minerals are elements found in the earth and in food, that we need to keep us healthy.

Roles of potassium:

Potassium has many roles, but here are the main ones.

• Nervous system: potassium is crucial for nerve signalling. The nervous system communicates with electric messages across nerve cells. These electric signals are generated by the action of potassium moving out of cells, and sodium moving in. Without these nerve signals, your brain wouldn’t be able to communicate with your body.
• Heart and muscle contraction: potassium’s role in the nervous system also means it’s essential for muscle contraction and for your heart beating. It makes sure your heart beats at the right pace by controlling the electrical signals in the heart. It also means your muscles can contract properly which is what allows you to move.

• Fluid balance: potassium also helps control the balance of fluid in your body. Potassium is the main molecule in the fluid inside your cells. Making sure your cells have the right amount of fluid in them is crucial and without potassium to help regulate this, your cells could shrink.

How much potassium should we be having?

The recommended amount of potassium for adults is 3500mg a day.

For reference, a medium banana has about 420mg of potassium. While everyone thinks of banana as the best source of potassium they’re actually not!

Foods that are high in potassium:

Here a few foods that are high in potassium. This isn’t a complete list, but most fruit, vegetables, beans, and meats are good sources of potassium.

• 1 medium potato (200g) contains ≈ 900mg
• 1 cup (180g) of cannellini beans contains ≈ 830mg
• 250ml of coconut water contains ≈ 600mg
• Half an avocado contains ≈ 500mg
• 1 chicken thigh (135g) contains ≈ 375mg
• 1 wedge of watermelon (300g) contains ≈ 320mg

What happens if you don’t get enough potassium?

A deficiency in potassium is called hypokalaemia. It’s rarely caused by a lack of dietary potassium and can instead by caused by excess fluid loss (e.g. diarrhoea) or other conditions.

Some of the symptoms of a low potassium are muscle weakness and cramps, irregular heartbeat, fatigue, and digestive issues. 

This is all due to potassium’s role in the nervous system. With the irregular heartbeat for example, as potassium helps regulate the heart’s pace, if there’s not enough potassium then the heart’s rhythm will be disrupted.

Key points:

• Potassium has many roles including heart and muscle contraction, controlling fluid balance in the body, and conducting nerve signals.
• Every adult should be getting 3500mg of potassium a day.
• Fruits, vegetables, beans, and meat are good sources of potassium.
• Low potassium is called hypokalaemia and can lead to an irregular heartbeat, muscle cramps and weakness, fatigue, and digestive issues.

 

I hope you enjoyed this blog post; I’d love to hear your thoughts in the comments below!

Bye for now! 👋

References:

Role: https://wtcs.pressbooks.pub/nursingfundamentals/chapter/15-2-basic-fluid-and-electrolyte-concepts/ and https://link.springer.com/chapter/10.1007/978-1-4615-1061-1_18#:~:text=When%20potassium%20enters%20the%20cell,the%20conduction%20of%20nerve%20impulses.&text=This%20electrical%20potential%20gradient%20helps%20generate%20muscle%20contractions%20and%20regulates%20the%20heartbeat.

Recommended amount: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/743790/Dietary_Reference_Values_-_A_Guide__1991_.pdf

Deficiency: https://www.healthline.com/nutrition/potassium-deficiency-symptoms#symptoms