Potassium (K)

What is potassium?

Potassium is an essential nutrient that helps us maintain a healthy blood pressure, allows our muscles to function properly, and supports our overall well-being. Potassium is also called an electrolyte, because it can conduct an electrical charge in the body. Since we cannot produce potassium by ourselves, we must get this nutrient through food.

Why we need it

Potassium is crucial for fluid balance, as it helps regulate how much water enters and exits our cells. This in turn prevents our blood volume from becoming too low or too high, helping us maintain a normal blood pressure.

Potassium also allows our muscles to contract and function properly. This is because potassium helps generate a cell membrane potential, which is the difference in electric charge inside versus outside of the cell. The cell membrane potential is necessary for muscle contractions and nerve impulses.¹

Potassium is required for many other cellular reactions, including those involved in energy production and acid-base balance. Additionally, getting enough potassium may help protect us against chronic disease. For instance, adequate potassium intake has been linked with a lower risk of heart disease, diabetes, and kidney disease.^{1, 2}

Where it’s found

Potassium is found in a variety of foods, particularly fruits and vegetables. It’s also found in some meats, grains, dairy products, and legumes. Additionally, you can get potassium from some salt substitutes, like salt-free seasoning. Specific examples of potassium-rich foods include:

Potassium can also be taken as a supplement, either alone or as part of a multivitamin. There are many forms of potassium used in supplements, such as potassium citrate, potassium aspartate, and potassium phosphate. There does not appear to be a large difference in how well these forms are absorbed and processed in the body.³

Daily requirements

The daily recommended amount of potassium is 400-860 milligrams (mg) for infants, 2000-2300 mg for children aged 1-8 years, 2300-2500 mg for adolescents aged 9-13 years, 3000 mg for male adolescents aged 14-18 years, 2300 mg for female adolescents aged 14-18 years, 3400 mg for men over the age of 19, and 2600 mg for women over the age of 19.⁴

Unfortunately, most people do not meet these dietary recommendations. For this reason, potassium is considered a nutrient of public health concern, and is now required to be listed on the nutrition facts label.⁵

Potassium deficiency

Although many people do not get sufficient potassium through foods, potassium deficiency is not so common. This is because our kidneys work hard to preserve potassium when we don’t consume enough of it. Nonetheless, inadequate potassium intake can still be harmful, as it can increase our risk of developing high blood pressure.¹

Severe potassium deficiency (called hypokalemia) can cause muscle cramping, heart arrhythmias, kidney dysfunction, and paralysis.¹ Hypokalemia may be seen in people with medical conditions (e.g., kidney disorders) that cause excessive potassium losses through the urine.¹ People who take diuretics, as well as people inflammatory bowel disease, may also be at higher risk for potassium deficiency.³

Can you get too much potassium?

Too much potassium may have negative effects. When potassium builds up in your blood, it can impair muscle function, potentially leading to muscle paralysis and heart arrhythmias, which can be fatal in severe cases.¹

Potassium toxicity is usually due to consuming excessive amounts of potassium from supplements, not from food. Thus, there is currently no Tolerable Upper Intake Level (a maximum amount of a nutrient that is considered safe) established for potassium.³

However, individuals with kidney disease may be at risk for potassium toxicity from food or supplements. This is because your kidneys are responsible for clearing potassium from your body, meaning that when the kidneys are damaged, toxicity is more likely. For this reason, people with kidney disease may be recommended to follow a low potassium diet.

Fun facts

Potassium works closely with another essential electrolyte: sodium. Together, potassium and sodium help maintain fluid balance and cell membrane potential. However, sodium (which most people consume too much of) is linked with an increased risk of high blood pressure, while the opposite is the case for potassium.¹

Potassium is a cation, which means it is positively charged. In fact, potassium is the major intracellular cation in our bodies, meaning it is the most abundant cation within our cells.²

References

1. McLean, R. M., & Wang, N. X. (2021). Potassium. Advances in food and nutrition research, 96, 89–121.
2. Stone, M. S., Martyn, L., & Weaver, C. M. (2016). Potassium Intake, Bioavailability, Hypertension, and Glucose Control. Nutrients, 8(7), 444.
3. National Academies of Sciences, Engineering, and Medicine. (2019). Dietary Reference Intakes for Sodium and Potassium. Washington, DC: The National Academies Press. https://www.ncbi.nlm.nih.gov/books/NBK538102/
4. U.S. Department of Health and Human Services. (2022). Potassium: Fact Sheet for Health Professionals. NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Potassium-HealthProfessional/#en1
5. US Food & Drug Administration. (2022). Changes to the Nutrition Facts Label. https://www.fda.gov/food/food-labeling-nutrition/changes-nutrition-facts-label

Food high in Potassium (K)

This list shows food that are top sources of Potassium (K) and the quantity of Potassium (K) in 100g of food