Potassium is something of an unsung hero among the essential minerals. While it doesn't attract the same attention as calcium or iron, your body relies on it for a long list of important functions, and most of it lives inside your cells – including the cells that make up your muscles. Here's what potassium does, where to find it, and when a supplement can help.
What is potassium?
Potassium is an electrolyte, which means it's a mineral that carries a small electric charge. That charge is what allows it to do its job, helping to send signals between cells throughout your body.
Your body can't produce potassium, so like other essential minerals, it all has to come from your diet. Fortunately it's found in a wide variety of foods, most of them plant-based, and it's also available as a supplement, either on its own or as part of a multivitamin. (A nice bit of trivia: potassium's old name is kalium, which is why its chemical symbol is K.)
Why do I need potassium?
Potassium has three well-established, authorised roles in the body:
- It contributes to normal muscle function
- It contributes to the normal functioning of the nervous system
- It contributes to the maintenance of normal blood pressure
That last one is worth understanding, because it's where potassium gets most of its attention. Potassium and sodium (salt) work in opposition to one another, and a diet that's richer in potassium and lower in salt helps the body keep blood pressure within a normal range. It's a good example of how two minerals balance each other rather than working in isolation.
What foods are rich in potassium?
Bananas get all the limelight, but they're far from the richest source. A medium banana provides around 10% of your daily requirement, while a baked potato eaten with the skin on delivers closer to 30%.
You'll find plenty of potassium in avocados, leafy greens like spinach, beans and pulses, squash and carrots, and dried fruit including apricots, peaches and raisins. Seafood is another excellent source, particularly wild salmon and yellowfin tuna, and there's a good amount in dairy foods like milk and yoghurt too.
One practical tip: potassium dissolves in water, so boiling vegetables and pouring the water away takes a good deal of it with them. Steaming, or using the cooking water in a soup or sauce, keeps more of it. The NHS recommends 3,500mg of potassium a day for adults aged 19 to 64, and you should be able to get all of it from a varied and balanced diet.
Do I lose potassium when I exercise?
A small amount, yes. You lose potassium through sweat, so intense exercise or spending time in a hot climate will deplete your levels a little – though rarely by very much. Any losses are easily replaced through food: a glass of tomato juice after a workout provides around 460mg of potassium, and a banana makes a popular and convenient post-exercise snack.
Should I take a potassium supplement?
The Department of Health and Social Care advises that you should be able to get all the potassium you need by eating a varied and balanced diet. For most people, then, a supplement isn't necessary.
Some people may find it harder, though. Conditions such as inflammatory bowel disease can affect how well you absorb potassium, and certain medicines, including laxatives and diuretics, can cause you to lose more of it than usual. If either applies to you, speak to your GP or pharmacist before taking a supplement.
Potassium is genuinely one of the minerals where it's important to stick to the recommended dose. The NHS advises that taking 3,700mg or less a day from supplements is unlikely to cause harm. Older adults in particular should be careful not to take potassium supplements unless a doctor has advised it, because the kidneys become less efficient at clearing potassium from the blood with age. If in any doubt, a quick word with your pharmacist is the right first step.
Which potassium supplement should I take?
Our selection includes:
- Vegetarian citrate capsules – potassium citrate is a well-absorbed, alkaline form of the mineral
- Potassium and magnesium citrate capsules – pairing two essential minerals in a highly absorbable form
- Premium tablets – made with naturally sourced ingredients, and suitable for vegans and vegetarians
- Electrolyte liquids – supplying potassium alongside other electrolytes in ionic form, with caffeine-free options suitable for use before and after exercise
- Mineral sachets – combining potassium with other essential vitamins and minerals
You'll also find supplements that blend potassium with minerals like magnesium, zinc, calcium and vitamin D – several of these contain nutrients that contribute to the reduction of tiredness and fatigue. Many of our supplements are suitable for vegetarians and vegans, but always check the product label for specific dietary information.
Explore our range of potassium supplements to support normal muscle function, the nervous system, and the maintenance of normal blood pressure.