Kidney Diet Tips

Potassium and Kidney Diets: More or Less?

Potassium is a mineral found all over the earth. It functions in the human body as an electrolyte. It plays a vital role in:

  • sending electrical signals in the body
  • helping regulate muscle contraction
  • maintaining healthy blood pressure
  • balancing water levels

As a renal dietitian, I have learned that many people with chronic kidney disease (CKD) get confused about potassium and how much they need each day.

What Determines Potassium Needs?

The need for more or less potassium depends on many things. Firstly, kidney function plays a big role – the less kidney function you have, the harder for your kidney to filter out extra amounts from your blood. As a result, potassium in the blood will increase when you eat more than the kidneys or dialysis can remove. Your healthcare provider will advise you to reduce the amount of potassium in your diet if a restriction is needed. Ask your healthcare provider what your level is, and if you need to limit high potassium foods. A normal level is 3.5 to 5.0 mg/dl for people who are not on dialysis. For those on dialysis the goal is 3.5 to 5.5 mg/dl. Levels that are too high or too low are dangerous for your heart.

Secondly, if you are already receiving kidney replacement therapy such as hemodialysis you will need to continue restricting potassium. However, if your levels are below 3.5 mg/dl, you could be restricting too much. Some hemodialysis patients who still have some kidney function, called renal residual function (RRF,) lose potassium in urine and during dialysis treatments. Patients on peritoneal dialysis, a treatment performed on a daily basis, have higher  losses than patients on hemodialysis 3x a week. Patients on home hemodialysis (HHD) dialyzing 5-6 times a week may have a higher potassium requirement. These patients might need to eat more potassium each day to prevent low levels.

Thirdly, there are many medications that might also play a role. Some examples are diuretics prescribed by your doctor to help you remove more fluid. Some blood pressure medications make the kidneys retain more potassium. These can contribute to higher levels. Always ask your healthcare providers about these and other medications you take.

Potassium-Lowering Medicine

On the other hand if your potassium levels are dangerously high, your doctor might prescribe medication to help decrease it. Most of my patients that have taken this type of medication dislike it greatly because of the unpleasant side effects.

Let your healthcare provider know about medications you are currently taking, so when your blood work is done, they know what might be causing a change in your levels.

Dietary Changes

A very good way to increase or decrease potassium in your blood is by making changes in your diet. Potassium is found in meats, nuts, fruits and vegetables. The secret here is to find out which foods have large amounts. For example, one avocado contains 700 to 900 mg of potassium. On the other hand, 5 to 6 strawberries contains about 100 mg. The internet is helpful, but make sure you are reading trustworthy sites. DaVita.com is a great resource to get more information and delicious recipes. Use the DaVita Diet Helper Food Analyzer to look up potassium in the foods you eat. Also learn to reduce potassium content of potatoes, sweet potatoes and other high potassium vegetables. Two methods are by double boiling, or by soaking 2 to 4 hours or overnight, then boiling. These processes decrease potassium by almost half.

Consult with a registered dietitian (RD) who specializes in kidney disease for more help with potassium and other dietary needs. Ask your doctor for a diet prescription and dietitian referral. Dietitian consultations are covered by the Medicare medical nutrition therapy (MNT) benefit when you have a diagnoses of chronic kidney disease (CKD) or diabetes. Most commercial (private) insurance also cover for this expense, but may require a doctor’s prescription.


Matilde Ladnier RD, LD

Matilde Ladnier RD, LD

Matilde is an adventurer who loves to cook, try new foods, travel (especially to her home country Peru) and play tennis. She has over twenty years of experience working with CKD patients and enjoys educating anyone who is willing to learn.