High-Potassium Foods to Avoid and Low-Potassium Swaps

Quick answer

Only limit potassium if your doctor tells you to

Healthy people with normal kidneys benefit from potassium-rich foods (fruit, vegetables, legumes), which also help blood pressure. People with advanced kidney disease, hyperkalaemia on blood tests, or those taking potassium-sparing diuretics, ACE inhibitors or ARBs may be advised to limit foods with more than about 200 mg of potassium per serving. High-potassium foods include bananas, oranges and orange juice, potatoes, tomatoes and tomato sauce, avocados, spinach, beans, lentils, dried fruit, melon and coconut water. Lower-potassium swaps include apples, berries, grapes, pineapple, cabbage, cauliflower, rice and pasta. Soaking and boiling vegetables can reduce potassium. Do not use salt substitutes containing potassium chloride unless approved.

Important. Muscle weakness, palpitations, a very slow or irregular heartbeat, breathlessness or fainting can indicate high potassium and need urgent medical care, particularly with kidney disease. Do not restrict potassium or start potassium supplements or salt substitutes without medical advice.

What potassium does and who needs to limit it

Potassium helps nerves send signals, muscles contract (including the heart), fluid balance and blood pressure. Kidneys remove excess potassium. When kidney function falls, or when certain medicines reduce potassium excretion, blood potassium can rise to dangerous levels. Typical situations that call for limiting potassium are chronic kidney disease stages 3b–5 and dialysis (depending on blood tests), acute kidney injury, adrenal problems and use of potassium-sparing diuretics (spironolactone, amiloride), ACE inhibitors, ARBs, trimethoprim or NSAIDs. See alimentos con potasio (Spanish).

Foods high in potassium

Fruit: bananas, oranges and orange juice, melon (cantaloupe, honeydew), kiwi, mango, papaya, apricots, prunes, raisins and other dried fruit, avocados, coconut water.
Vegetables: potatoes (including fries and crisps), sweet potatoes, tomatoes and tomato sauce, spinach, Swiss chard, beet greens, pumpkin, winter squash, mushrooms, Brussels sprouts.
Legumes: beans, lentils, chickpeas, soybeans.
Other: milk and yoghurt, bran cereals, nuts and seeds, chocolate, salt substitutes (potassium chloride), some sports drinks and supplements.
Approximate values come from USDA FoodData Central: a medium banana has about 420 mg, a baked potato with skin about 900 mg, and a cup of cooked spinach about 840 mg.

Lower-potassium choices

Fruit: apples, pears, grapes, berries, pineapple, peaches (canned and drained), watermelon in small portions, cranberry juice.
Vegetables: cabbage, cauliflower, carrots (cooked), cucumber, lettuce, onions, peppers, green beans, courgette, aubergine.
Grains and starches: white rice, pasta, white bread, couscous, noodles.
Protein: eggs, chicken, fish and meat in moderate portions (they contain moderate potassium).
Others: rice milk (check labels), herbs and spices for flavour.
Portion size matters: even low-potassium foods add up if eaten in large amounts.

Easy swaps

Banana → apple, grapes or blueberries.
Orange juice → cranberry or apple juice (small glass).
Baked potato or fries → white rice, pasta or leached potato.
Tomato sauce → olive oil with garlic and herbs, or a small amount of homemade sauce.
Spinach salad → lettuce, cabbage or cucumber salad.
Dried fruit → fresh berries or canned pineapple.
Salt substitute → herbs, lemon, garlic and spices.

Cooking tricks to reduce potassium

Potassium dissolves in water, so preparation reduces it. Peel and cut potatoes and other vegetables into thin slices, soak them in warm water for at least 2 hours (some guides say overnight), rinse, then boil in plenty of fresh water and discard the water. This “leaching” can remove up to half of the potassium, though not completely. Avoid using cooking water in soups or sauces. Canned vegetables and fruit, drained, usually contain less potassium than fresh because some leaches into the liquid, but they can be high in sodium, so rinse them.

Hidden potassium: labels and additives

Salt substitutes (“lite salt”) and some low-sodium products use potassium chloride.
Sports drinks, protein shakes and some “healthy” juices may be rich in potassium.
Potassium additives (potassium chloride, potassium lactate, potassium sorbate) appear in processed foods.
Supplements and herbal products can contain potassium.
Read labels and ask a renal dietitian about particular products.

If you do not have kidney disease

Most people should not avoid potassium-rich foods: a diet high in potassium from fruit, vegetables and legumes lowers blood pressure and stroke risk. See DASH diet. Restrict potassium only on medical advice. Many people with early kidney disease do not need restriction, and a renal dietitian individualises advice based on blood tests.

Monitoring and medicines

Blood tests of potassium and kidney function guide advice.
Report muscle weakness, palpitations, or nausea to your doctor.
Ask before taking supplements, salt substitutes or new medicines.
Never stop prescribed medicines because of potassium without medical advice.
In dialysis, potassium limits depend on the type and schedule of treatment.

When to seek help

Kidney disease with potassium restrictions or high potassium on a blood test.
Palpitations, muscle weakness or slow irregular pulse (urgent).
Taking ACE inhibitors, ARBs, spironolactone or other potassium-affecting medicines.
Uncertainty about which foods to limit: ask a renal dietitian.
Diarrhoea, vomiting or dehydration, which can quickly change potassium levels.

Three common situations

A person with stage 4 kidney disease and potassium of 5.8 mmol/L: work with a dietitian on specific swaps and cooking methods.

Someone on spironolactone who loves bananas and orange juice: check blood potassium and ask your doctor about limits.

A healthy person worried about potassium: no need to restrict; eat plenty of fruit and vegetables.

Key points to remember

Limit high-potassium foods only if your doctor advises it. Swap bananas, oranges, potatoes, tomatoes and beans for lower-potassium choices, use leaching and avoid potassium salt substitutes. Our nutrition team can help you with a kidney-friendly plan.

This guide is for general information and does not replace an assessment by your own doctor or dietitian.

Questions about high-potassium foods to avoid

These answers are general information and do not replace an examination or individual medical advice.

What fruits are highest in potassium?

Bananas, oranges, melons, kiwi, mango, apricots, prunes and dried fruit.

Do I need to avoid potassium with kidney disease?

Only if blood tests show high potassium or your kidneys cannot remove it; advice is individual.

Can I eat potatoes on a low-potassium diet?

Leached (soaked and boiled) potatoes in small portions may be allowed; fries and baked potatoes are high.

Are salt substitutes safe?

Many contain potassium chloride and can be dangerous with kidney disease or some medicines.

What are low-potassium vegetables?

Cabbage, cauliflower, carrots, cucumber, lettuce, onions and green beans.

What are the symptoms of high potassium?

Muscle weakness, palpitations, nausea and, in severe cases, dangerous heart rhythms; it often causes no symptoms until severe.

Sources

This guide is for general information and does not replace medical advice. How a problem is diagnosed and treated depends on your examination and medical history. If you think you have an emergency, contact your local emergency services.