Low potassium diet - information for kidney patients

This page contains advice on:

• High potassium foods and low potassium options
• Information on the best way to cook foods
• Choosing the right portion size to eat

What is potassium?

Potassium is a mineral found in many foods. It helps our nerves, muscles and heart to work well.

Our kidneys help to control the level of potassium in the blood. Extra potassium leaves the body in the urine.

Why is my potassium high?

• Your kidneys are not working well.
• You may be eating a high potassium diet.
• There are other medical reasons which might cause your potassium to be high.

What should my potassium be?

A healthy potassium level is between 3.5 - 5.5 mmol/l, unless you have been advised differently by your healthcare professional. The only reliable way to measure your potassium level is a blood test.

Why do I need to control potassium in the blood?

Both high and low potassium can change the way your heart beats.

What can I do to control high blood potassium?

• Choose low potassium foods.
• Ensure your bowels open regularly.
• If you have diabetes keep your blood glucose in your target range.
• If you have dialysis, attend all of your sessions.

Do I have to limit all high potassium foods?

You may not need to. Your dietitian can advise you.

Are there any foods I don’t have to reduce?

Protein foods such as beans, lentils, tofu and Quorn contain potassium but can be included in vegetarian meals instead of meat. The information further down this page provides more guidance on these. Vegetarian meals can help manage potassium levels. Ask your dietitian for more information.

Other protein foods such as meat, fish, eggs, and cheese also contain potassium but can still be eaten.

Pasta, rice, couscous, bread and noodles are low in potassium. Choosing wholegrain varieties can help to reduce your potassium level.

Can I eat fruit and vegetables?

Yes. Aim for five servings of lower potassium fruit and vegetables per day.

Potassium additives

These are used to preserve and flavour foods so are often found in processed foods. Your body absorbs potassium additives very easily.

You will find them listed on the ingredients label if they are added to food. By checking food labels and eating less of these additives you can help prevent high potassium levels in your blood.

Common potassium containing additives include:

• Potassium chloride.
• Potassium sorbate.
• Potassium phosphates.
• Potassium nitrate.
• Potassium citrate.
• Potassium lactate.

Look out for potassium additives in all foods but especially in:

• Those labelled ‘reduced salt’ or ‘low salt’.
• Crisps and savoury snacks.
• Cold cooked meat (such as ham).
• Soft drinks.

Snack foods

Cereals, cakes, biscuits

Spreads

Soups

Seasonings, condiments

Drinks

Fruits and vegetables

Fruits and vegetables naturally contain potassium and are high in fibre.

Your body absorbs less potassium from high fibre foods. Fibre helps you have a healthy gut and regular bowel movements. This also helps lower potassium levels in the blood. Aim to choose lower potassium fruit and vegetables.

Eating more fibre in your diet reduces your risk of type 2 diabetes and bowel cancer.

Vegetables

Fruit

How to reduce the potassium in potatoes and vegetables

• Peel potatoes, cut up and boil in water. Do not use this water for gravy, soups, or sauces.
• Boil vegetables and potatoes before adding to stir-fries, stews, or casseroles.
• Part boil before roasting and frying. Try not to cook
  vegetables and potatoes in the steamer, microwave, airfryer or pressure-cooker .
• Boil cassava, sweet potato and yam if you are having
  these. Try not to have potatoes at that meal.

What if I eat a vegetarian or vegan diet?

If your meal does not contain meat, chicken or fish then you can include one of the following:

• 200g Baked Beans
• 200g Tofu
• 200g Quorn
• 200g Lentils*
• 200g Chickpeas* 
• 200g Beans* (e.g. canned broad, kidney, butter beans, haricot, mung and black eyed beans)
• 200g Hummus^

* cooked weight

^ lower in protein

How do I reduce the potassium in these foods?

• Drain, rinse and boil all types of beans and lentils before adding to meals. This includes curries, stews and casseroles.
• Choose canned beans or lentils as they are lower in potassium.
• If using dried beans or lentils, soak overnight in plenty of water.
• Discard the water used for soaking or boiling.

Are there any vegetarian foods I should avoid?

• Soya beans, aduki, pigeon and pinto beans are higher in potassium. Reduce or limit these.
• Nuts and seeds
• If you avoid potatoes, then you can have another portion of beans, lentils or meat alternative.

Ask your dietitian if you need further help.

Foods high in salt and sugar

This page gives a full range of low and high potassium foods.

It includes some foods that are high in salt and sugar such as savoury snacks, cakes and sweets. These are included to give a variety of options. You may prefer not to eat these foods if you are reducing salt in your diet or if you have diabetes.

What if the foods I eat are not on this page?

You can contact your renal dietitian on 0117 414 5428.

Websites

Patients Know Best

An easy-to-use online service that allows you to monitor your own blood test results.

You can find out more and register to use it at Register to Patients Know Best - Patients Know Best

Kidney Kitchen

Kidney-friendly cooking and eating: information, recipes and Kidney Kitchen videos.

Visit the website at Kidney Kitchen | Kidney Care UK

© North Bristol NHS Trust. This edition published June 2023. Review due June 2026. NBT003377