Potassium and your blood pressure

Potassium is an essential mineral that your body needs to function properly, and helps to lower your blood pressure.

Eat a range of foods that are high in potassium, especially fruits and vegetables, to help keep your blood pressure under control.

How does potassium help to lower your blood pressure?

Potassium plays a role in how much fluid is stored in your body, and how much is released in your urine. If your body is holding onto water, there will be more fluid in your blood. This puts extra pressure against your blood vessels walls, raising your blood pressure.

Normally, excess fluid is removed from your blood by your kidneys and filtered into the bladder. This process involves a fine balance of sodium and potassium.

Sodium is the part of salt that puts up our blood pressures. If you eat too much salt, there will be more sodium in your blood, and the sodium holds onto water. This upsets the fine balance of sodium and potassium that is needed for water to be pulled out of the blood and into the kidneys.

By eating more foods that are high in potassium, you can help to restore the balance, allowing the kidneys to work well and lower your blood pressure.

How to eat more potassium

Fruits and vegetables

Fruit and vegetables are a great source of potassium. Plus they’re full of vitamins, minerals and fibre which keep your body in good condition, helping to prevent bowel problems and some cancers as well as heart disease and stroke.

Aim for at least five portions of fruit and vegetables every day.

Fruits that are particularly high in potassium include:

• tomato juice and tomato puree
• orange juice
• bananas
• apricots
• currants

Vegetables that are particularly high in potassium include:

• potatoes
• sweet potatoes
• asparagus 
• spinach 
• cabbage
• sprouts
  
  

Other foods high in potassium 

There are a number of other foods which are high in potassium, as well as other helpful vitamins and minerals.

These include:

• tuna – fresh, frozen or tinned, but go for tuna tinned in spring water rather than brine, as brine contains salt
• salmon
• yoghurt
• fat-free milk 
• eggs 
• macadamia nuts
• almonds
• mushrooms
• bran
• wheatgerm
• wholemeal pasta

As well as eating foods high in potassium, cutting down on salt will help to keep your kidneys and blood pressure in good health.

Potassium supplements and your kidneys

It’s possible to have too much of a good thing. To make sure you don't overdose on potassium, avoid taking supplements and get your daily potassium from fruits and vegetables and the other foods listed here.

If you have kidney disease or are taking certain blood pressure medications, a large increase in potassium could be harmful. If this applies to you, avoid taking potassium supplements or switching to potassium-based salt alternatives, and check with your doctor before dramatically increasing your potassium intake.

Low-sodium salt alternatives

If you’re trying to cut down on salt but are finding it hard to cook without adding salt, there are low-sodium alternatives to salt which you can buy to season your food. These give food the same salty flavor but contain much less sodium.

These products contain potassium instead of sodium. They could help you to lower your blood pressure if you use them instead of salt, but don’t add them to food to top up your potassium intake.

If you have kidney problems or diabetes, check with your doctor or nurse before using the products as they might not be suitable for you.

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