Why a Low Potassium Diet Is Important for CKD Patients

People with advanced chronic kidney disease (CKD) have progressively declining kidney function. Doctors frequently advise such individuals to avoid potassium-rich foods. Please keep reading to find out why CKD patients are advised potassium-restricted diets and how much potassium certain foods contain.

What is potassium?

Potassium is an important mineral (electrolyte) that plays a role in nerve and muscle function, fluid and electrolyte balance, bone health, and digestion in the body. We get potassium from the food we eat. Healthy kidneys remove excess potassium from the body to keep the amount of potassium in the body balanced.

Normal potassium levels in adults are between 3.5 and 5.2 mEq/L. A potassium level below this range is called hypokalemia (low potassium). It can lead to abnormal heart rhythms and muscle weakness. Low potassium level is rare in people who eat a balanced, healthy diet. Medical conditions such as eating disorders, alcohol use disorders, excessive sweating, kidney disease, adrenal disorders, and certain medications like diuretics (water pills) can increase the risk of hypokalemia.

A potassium level above the normal range is called hyperkalemia (high potassium). High potassium levels can cause nausea, vomiting, abdominal pain, chest pain, heart palpitations, muscle weakness, and numbness. Hyperkalemia risk factors include chronic kidney disease and increased potassium intake through high-potassium foods, potassium supplements, and potassium-containing salt substitutes.

Why is controlling potassium important for patients with chronic kidney disease?

In patients with chronic kidney disease, there is declining renal function (the kidneys do not work properly). As a result, the kidneys are unable to remove excess potassium from the body, causing potassium levels to build up. Therefore, people with reduced kidney function are at risk of hyperkalemia (high potassium levels). Dialysis can help to regulate potassium levels in people with advanced kidney diseases. However, a healthcare provider may recommend potassium restriction to keep potassium levels in check between dialysis treatments.

What are low and high potassium foods?

According to the National Kidney Foundation, foods that contain 200 mg of potassium or more per serving are classified as high potassium foods. Here are some examples of foods, from fruits and vegetables to packaged foods and processed foods, that you can exclude or include as part of a low-potassium diet.

High potassium foods

High-potassium vegetables include black beans, dried beans, cooked broccoli, Brussels sprouts, carrots, cabbage, lentils, okra, potatoes, pumpkin, spinach, winter squash, tomatoes, tomato juice, tomato sauce.
Fruits high in potassium include apricots, avocados, bananas, cantaloupe, dates, kiwi, mango, melon, orange, orange juice, papaya, prune juice, and pomegranate.
Other foods higher in potassium content include milk, yogurt, chocolate, granola, chicken, beef, salmon, nuts, and seeds.

Low potassium foods

Low-potassium vegetables include asparagus, raw broccoli, green beans, cauliflower, celery, corn, cucumber, eggplant, kale, lettuce, onions, peas, peppers, radish, and zucchini.
Fruits low in potassium include apples, berries, grapes, canned fruits like peaches and pears, pineapples, plums, and watermelons.
Other low-potassium foods are breads, cakes, pasta, noodles, pies, coffee, and tea.

It is worth noting that even low-potassium foods contain some potassium. Therefore, eating large quantities of low-potassium foods can lead to more potassium intake and high potassium levels.

Tips on following a renal diet

Here are some tips to help you eat a kidney-friendly diet that is low in potassium, while still eating some of your favorite foods and maintaining good nutrition:

If you love certain high-potassium vegetables, leaching them (soaking them in water for at least 2 hours) may remove some of the potassium and allow you to enjoy them occasionally.
You can reduce your potassium intake by discarding the liquid in canned vegetables and fruits.
To help keep your potassium level within normal limits, read food labels for potassium chloride content.
Practice portion control when eating high potassium foods.
Remember that salt substitutes and other seasonings often contain potassium.
Limit milk and milk products or use milk substitutes.
Consult a renal dietitian to help you fine-tune your CKD diet.
Take your kidney medicine and go for dialysis treatments as recommended.

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