A high level of potassium in the blood, or hyperkalemia, is a serious condition that can cause heart problems and even death, according to the National Kidney Foundation (NKF). Yes, there's a link between high potassium levels and cancer — but it may not be what you think.
Read more: What Do You Eat If You Have High Blood Potassium?
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What Is Potassium?
Potassium is an electrolyte. It's a mineral in the body that carries an electric charge. It's essential for survival, because it helps our muscles work, including muscles that control our heartbeat and breathing, says the American Kidney Fund (AKF).
And AKF explains: Our kidneys remove the extra potassium that our bodies don't need through our urine. But potassium can build up in the bloodstream if:
- You have kidney disease, uncontrolled diabetes or some other rare illnesses that make it hard to remove extra potassium.
- You consume an excess of high-potassium foods, additives and salt substitutes.
- You take certain prescription drugs.
While there's no evidence that high potassium causes cancer, studies have pointed to a possible connection. A January 2020 study published in the journal Clinical Epidemiology followed nearly 2,000 Norwegian men for 40 years and found an association between high potassium levels and long-term cancer risk.
Men with high potassium levels were 40 percent more likely to have cancer than men with normal potassium levels, the study found. This increase was seen for cancers of the pancreas, stomach, lung and prostate. The study couldn't determine if high potassium levels cause cancer, but the findings could suggest that higher levels of potassium may promote cancer growth due to its effect on the immune system.
Scientists at the National Cancer Institute's Center for Cancer Research (NCI) found that potassium may indeed play a role in the immune system. They found that high levels of potassium inside tumors weaken the body's immune response, according to their September 2016 study in the journal Nature.
That's because the T cells — which are part of our body's immune response — "were suppressed by the potassium, so their normal function to destroy cancer was inhibited," says Portland, Oregon-based Robert Eil, MD, assistant professor of surgery at Oregon Health & Science University, one of the study authors.
It's important to note that the tendency of potassium to suppress an immune response isn't always a bad thing, according to the NCI. It can be helpful in controlling the immune response when we have an injury, for example. But when it comes to cancer, having a high potassium level can make it more difficult for your cells to fight the battle.
Symptoms of High Potassium
Most people with high potassium don't feel any symptoms, according to the NKF. When they do, some of the most common ones are:
- Muscle pains or cramps.
- Trouble breathing.
- Unusual heartbeat or palpitations.
- Chest pains.
Patients also may also report paresthesia, a tingling, numbing or burning sensation in the hands, feet, arms or legs, NKF notes.
An estimated 2 to 3 percent of the population has hyperkalemia, NKF reports, and people with chronic kidney disease, heart failure, diabetes and people taking certain blood pressure medications have a much higher risk. Hyperkalemia often has no warning signs, but it can be easily checked in a routine blood test, it says.
Treating High Potassium
High potassium can be treated through diet, medicine or both, according to the AKF. Medications for hyperkalemia are called potassium binders, because they work by bonding to the potassium, preventing some of it from being absorbed into the bloodstream.
Changing what you eat can also lower potassium levels. People with hyperkalemia should avoid high-potassium foods like bananas, beans, potatoes, nuts and salt substitutes. They should also steer clear of many fruit juices, like orange juice and tomato juice.
Take a look at the nutrition label on packaged foods too, because, as AKF points out, food makers are now required to list potassium there. It may also be included in the ingredient list or with the abbreviation K, KCL or K+.
Read more: Low Potassium Food List
- National Kidney Foundation: “Facts About High Potassium in Patients With Kidney Disease”
- National Cancer Institute: Center for Cancer Research: “High Levels of Potassium Inside Tumors Suppress Immune Activity”
- American Kidney Fund: “What Is High Potassium, or Hyperkalemia?”
- Nature: “Ionic Immune Suppression Within the Tumour Microenvironment Limits T Cell Effector Function”
- Clinical Epidemiology: “Fasting Serum Levels of Potassium and Sodium in Relation to Long-Term Risk of Cancer in Healthy Men”
- Robert L. Eil, MD, assistant professor of surgery, Oregon Health & Science University, Portland, Oregon