How Potassium Helps the Body

Medically Reviewed by Jabeen Begum, MD on May 08, 2024
Written by R. Morgan Griffin, Alyson Powell Key
5 min read

Potassium is a mineral that's crucial for life. It's necessary for the heart, kidneys, and other organs to work normally. Your kidneys are responsible for keeping your body's potassium balance. Potassium:

  • Keeps your heartbeat regular
  • Moves nutrients in and waste products out of your cells
  • Counteracts the harmful effects of sodium on your blood pressure

Is potassium an electrolyte?

Yes. Electrolytes help control fluid levels, nerve and muscle activity, the body's pH (acid-base) levels, and more.

 

Most people who eat a healthy diet should get enough potassium naturally. Experts link low potassium to a higher chance of certain health conditions. Eating more of it could mean you're less likely to have:

High blood pressure and stroke

High blood pressure and stroke are closely connected. Low potassium levels, especially coupled with a high-sodium diet, raise your chance of high blood pressure. Boosting potassium and eating less salt can potentially lower blood pressure and your odds of having a stroke.

Kidney stones

A lack of potassium can lead to kidney stones by depleting calcium from bones and increasing its level in urine, causing the formation of painful stones. More potassium in your diet may lower your chances of kidney stones.

Weak bones

Potassium-rich fruits and vegetables may improve bone health by boosting bone mineral density.

Type 2 diabetes

Low potassium levels may raise blood sugar levels, potentially increasing the risk of insulin resistance and type 2 diabetes, but further research is needed to be sure.

Arthritis

Getting potassium through foods and supplements could help ease joint pain and improve rheumatoid arthritis. But we still need more studies to be sure it works.

Cancer

The right amount of potassium could protect you against cancer. One study found a link between potassium and a lower chance of lung cancer.

Infertility

Electrolytes such as potassium play a major role in fertility. For men and people assigned male at birth (AMAB), an electrolyte imbalance might mean lower sperm movement and other fertility problems. For women and people assigned female at birth (AFAB), it can disrupt the fluid around your eggs, which stops the eggs from growing properly and being able to get fertilized, leading to infertility.

For people with low potassium, doctors sometimes recommend improved diets -- or potassium supplements -- to prevent or treat some of these conditions.

An average blood potassium level is 3.6 to 5.2 millimoles per liter (mmol/L). Potassium deficiency (also called hypokalemia) is more common in people who:

  • Use certain medicines, such as diuretics
  • Have physically demanding jobs
  • Exercise in hot climates and sweat excessively (such as athletes)
  • Have health conditions that affect their digestive absorption, such as Crohn's disease
  • Have an eating disorder
  • Smoke
  • Abuse alcohol or drugs
  • Sweat too much
  • Have diarrhea
  • Vomit
  • Take certain antibiotics

Severe potassium deficiency isn't all that common. About 14% of people tested outside the hospital might have a slight lack of potassium in their blood. When people are in the hospital, around 20% might have low potassium levels. Symptoms of low potassium can include:

  • Weakness
  • Fatigue
  • Muscle cramps
  • Constipation

As potassium deficiency is rare, there is no recommended dietary allowance (RDA) or recommended nutrient intake (RNI) for it. However, the National Academy of Medicine has set an adequate intake for potassium. Getting this amount of potassium from your diet, with or without supplements, should be enough to keep you healthy. The FDA has determined that foods must contain at least 350 milligrams of potassium and 140 milligrams or less of sodium to be able to use the label: "Diets containing foods that are good sources of potassium and low in sodium may reduce the risk of high blood pressure and stroke."

Category

Adequate Intake (AI)

CHILDREN

0-6 months

400 milligrams/day

7-12 months

860 milligrams/day

1-3 years

2,000 milligrams/day

4-8 years

2,300 milligrams/day

9-13 years

2,500 milligrams/day

14 years and up

2,300 milligrams/day

ADULTS

18 years and up

3,400 milligrams/day

People w ho are p regnant

2,600-2,900 milligrams/day

People who are ch estfeeding

2,500-2,800 milligrams/day

Always take potassium supplements with a full glass of water or juice.

There is no set upper limit for potassium. So, it's not clear exactly how much potassium you can take safely. However, very high doses of potassium can be deadly.

It's best to get your potassium from foods rather than supplements. Lots of fruits and veggies are packed with potassium. Also, diets rich in potassium usually have less sodium. Good natural food sources of potassium include:

  • Bananas
  • Avocados
  • Peanuts and tree nuts such as almonds, pecans and walnuts
  • Citrus fruits
  • Leafy, green vegetables
  • Milk
  • Potatoes

Keep in mind that some types of cooking, such as boiling, can decrease the potassium content in some foods.

The only time you'll need a potassium supplement is if you're not getting enough in your diet or have lost too much of the mineral due to illness or other causes. Otherwise, the food you eat is a good source of potassium.

Potassium supplement side effects

Potassium can be dangerous in high doses. Possible side effects include:

  • Stomach upset
  • Allergic reaction
  • Muscle weakness or paralysis
  • Cardiac conduction abnormalities
  • Cardiac arrhythmias (sinus bradycardia, sinus arrest, slow idioventricular rhythms, ventricular tachycardia, ventricular fibrillation, and asystole)

Do not take potassium supplements without talking to your doctor, especially if you have kidney disease, diabetes, heart disease, Addison's disease, stomach ulcers, or other health problems. You should also avoid them if you take certain medications such as angiotensin-converting enzyme (ACE) inhibitors, potassium-sparing diuretics, or a trimethoprim-sulfamethoxazole antibiotic (Bactrim, Septra).

Get emergency help right away if you have any of the signs of a potassium overdose (also called hyperkalemia), which include: 

You may have a higher chance of hyperkalemia due to:

  • Chronic kidney disease
  • Diabetes
  • Heart failure
  • Medicines that cause a potassium imbalance, such as those that lower blood pressure

Depending on the cause of your dangerously high potassium level, treatments include:

  • Kidney dialysis
  • Medication to help get rid of potassium in your intestines
  • Sodium bicarbonate
  • Water pills (diuretics)

Potassium is important for your body, as it helps your heart, kidneys, and other organs work right. Usually, if you eat well, you'll get all the potassium you need, but some people might need more through supplements. Good natural sources of potassium include bananas, avocados, nuts, citrus fruits, veggies, milk, and potatoes.