Especially with advanced kidney disease, your blood potassium levels can rise. If your blood potassium levels are too high, you should definitely make sure that you do not take in too much potassium through your food. But what exactly is the connections between potassium and kidney disease?
Potassium - the engine for your muscles
Potassium is responsible for many different tasks in your body. Potassium is an important basic building block of all your body cells and regulates the amount of fluid in a cell. Potassium is also responsible for the transmission of stimuli in your nerves, i.e. communication in your body. In addition, it is also involved in the control of your muscles. Almost 99% of potassium is found in the cells of the body and only 1% is found in the blood.
The kidneys are largely responsible for regulating your body's potassium levels. Potassium enters your body through your diet because all foods contain potassium (some more than others). The job of your kidneys is to then keep the potassium level in your blood in balance. If your kidneys no longer function properly, this potassium balance is disrupted. As kidney function declines, especially in later stages of kidney disease, potassium levels in your blood rise. Your medical team refers to this as hyperkalemia. You can recognize this drop in kidney function by the lab value eGFR (=glomerular filtration rate), which describes how well your kidney can filter your blood.
What are hyperkalemia & hypokalemia?
Both hyperkalemia and hypokalemia can occur with kidney disease: If your blood potassium levels are high, your doctors will refer to it as hyperkalemia. This means you have too much potassium in your body. If your potassium levels are high, it's important to make sure you're taking in less potassium through your diet.
Occasionally, the opposite occurs where people with kidney disease have hypokalemia. Diarrhea, vomiting, or diuretic medications can also cause too little potassium to be in the body.
For most people with kidney disease, too much potassium is more of a challenge than too little. However, not all people with chronic kidney disease struggle with their potassium levels.
Blood potassium levels sometimes fluctuate relatively quickly
If your kidney disease is still at an early stage, chances are high that your potassium levels are still okay. As kidney function declines, your potassium levels can rise for a variety of reasons. This can also sometimes happen quite quickly, for example, if you are prescribed new medications that can affect the potassium levels in your blood.
From stage G3 (equivalent to an eGFR of less than 60 mL/min) of chronic kidney disease, the KDOQI guidelines recommend monitoring dietary potassium intake more closely and adjusting it to your individual potassium levels and their possible fluctuations. Both your personal health care team and the Mizu app can help you with this.
What is the approximate target level for potassium?
In healthy people, the approximate normal range for potassium in blood plasma is between 3.5 and 5.0 mmoL per liter. These target ranges also apply in chronic kidney failure. The upper normal range may be slightly different from lab to lab. It is best to ask what it is at your center. Hyperkalemia refers to potassium levels above 5.0 mmoL per liter (or above the upper normal range). If the potassium level exceeds 5.9 mmoL per liter, the patient has moderate to severe hyperkalemia, which should be treated quickly. Levels above 6.5 mmol per liter are always classified as severe hyperkalemia and are very dangerous.
Do I feel that my potassium is too high or too low?
A slight excess of potassium can be tricky, because it does not necessarily cause symptoms. Sometimes it can lead to tingling or numbness of the skin, diarrhea or muscle weakness. In more serious cases, muscle paralysis is sometimes reported. If potassium levels skyrocket, it can lead to very dangerous heart palpitations and arrhythmias.
On the other hand, if your potassium levels are too low, you may experience muscle weakness, cramping, or muscle spasms. The muscles of your digestive tract can also be affected, leading to constipation, for example. Low potassium levels, like high potassium levels, can also cause heart palpitations and arrhythmias.
After reading the sections above, you can now see why potassium is tricky: Since you don't always strongly feel a potassium level that is too high or too low, you should pay special attention that your level is in the green zone - even if you feel good.
So how can I reduce potassium?
Remember: You should only reduce your potassium intake if your potassium levels are too high or if the progression of your kidney disease makes it necessary. Your doctor may prescribe medications called potassium binders. In general, it is much more important that you also make sure to control potassium through your food intake. You can achieve this in two different ways:
- Your food selection: Potassium is found in all foods. In the context of kidney disease, it is important to look at which foods contain a lot of potassium and which contain little potassium. Plant-based food especially can contain relatively high levels of potassium.
- The preparation of your food: Potassium is water soluble. On the one hand, that's good, but on the other hand, it partly contradicts "healthy" cooking methods. You can cook things longer to reduce their potassium content. Since hot water removes potassium, it's better to throw away the potassium-rich cooking liquid and not use it again. In the Mizu app you can also find many other tips & tricks on how to cook delicious things in a potassium-conscious way.
How much potassium should I consume daily & when should I reduce potassium?
For people with healthy kidneys, a wholesome mixed diet including beverages contains about 4700 mg of potassium per day. For people with kidney failure, 3000mg is usually the maximum daily guideline, depending on how high the blood potassium is. In stage G3 and above an eGFR of less than 60 ml/min, a restriction may be appropriate, depending on laboratory values. In any case, you should talk to your nephrologist, dietitian or nutritionist for an exact determination of your daily guideline value.
Since the total amount of potassium is important, you may also already realize that you don't necessarily need to completely eliminate certain foods from your daily routine. It is more important that the total daily amount of potassium is adapted to you. There are, however, one or two potassium "bombs" that you should stay away from completely.
You can set your daily guideline in the Mizu app in the settings. This will help you better interpret the food in the food search. You'll also find plenty of other tips on how to better manage your potassium in the Mizu app.
