- Potassium plays a vital role in nearly every aspect of our health.
- It’s responsible for regulating fluid balance and blood pressure, maintaining heart and kidney function, helping to contract muscles and transmit nerve signals, and playing a role in preserving bone density.
- Eating a balanced diet that includes a variety of foods is important for getting adequate potassium every day. Many people consume less than the recommended amount of this nutrient.
Potassium is a mineral found in many foods that is critical for human health. Along with sodium, chloride, calcium and a few other electrolytes, it plays a primary role in maintaining normal water and fluid balance. It’s also a key player in muscle contraction, nerve transmission, blood pressure regulation, preservation of bone density and heart and kidney function.
Our bodies are unable to produce potassium, so it must be obtained through our diet. Many foods provide potassium, including fruits, vegetables, nuts, beans, dairy products, meats, poultry and fish. It can also be found in salt substitutes in the form of potassium chloride. People who consume a balanced diet can meet their daily potassium needs; however, many Americans consume less of this nutrient than is recommended.
Potassium and health
In addition to its important functions related to fluid balance, muscle contraction and nerve transmission, some of potassium’s important roles in human health include:
- Regulating blood pressure: high potassium intakes may help lower blood pressure, by dilating blood vessels and helping the body excrete sodium and water. High blood pressure is a risk factor for cardiovascular disease, so getting enough potassium may reduce risk for serious cardiac events, like strokes.
- Reducing risk for kidney stones: not getting enough potassium leads to more calcium loss from bones and increased calcium excreted in urine, which can lead to kidney stone formation.
- Preserving bone density: Observational studies have shown that people with higher potassium intakes tend to have higher bone density. The exact reasons behind this association is not known, but a few randomized controlled trials have supported this connection.
Health Effects of Potassium Deficiency
Potassium deficiency can be caused by very low potassium intake, diarrhea or vomiting, and/or use of laxatives, diuretics and certain medications. Low levels of potassium in the bloodstream is called hypokalemia, a condition with side effects like headaches, fatigue, muscle weakness, heart palpitations and swelling of glands. Severe hypokalemia can be life-threatening, since potassium is critical for the muscle contractions responsible for keeping the heart beating.
Health Effects of Excess Potassium
In healthy people with properly functioning kidneys, high potassium intake from foods is not harmful because it can be excreted from the body. It’s possible to consume too much potassium from very large dose of dietary supplements, though this is rare since many supplements only contain a small percentage of total daily potassium needs.
In 2019, the Health and Medicine Division of the National Academies of Sciences, Engineering and Medicine updated the Adequate Intakes (AIs) for potassium, which differ depending on age, sex and pregnancy or lactation.
Adequate Intakes (AIs) for potassium (milligrams (mg)/day)
Despite its common presence in the food supply, many people in the United States consume less potassium than is recommended. This observation, coupled with potassium’s vital role in human health, led to the 2015-2020 Dietary Guidelines for Americans naming potassium as a “nutrient of public health concern”. This, in turn, led to the Food and Drug Administration’s decision to make potassium labeling mandatory on the Nutrition Facts label, beginning in 2020 for large food producers.
Food sources of potassium
Potassium is found in a wide variety of food and beverages, including fruits, vegetables, nuts, beans, dairy products, meats, poultry and fish. In the U.S, sources such as coffee, tea, dairy products and potatoes are top contributors to potassium intake. The Dietary Approaches to Stop Hypertension (DASH) diet is an example of an eating pattern that includes many potassium-rich foods and has been shown to reduce blood pressure in randomized trials.
Sources of potassium
|Food||Serving Size||Potassium Content (mg)|
|Salmon, baked||1 medium fillet||1050|
|Potato, baked, flesh and skin||1 medium||610|
|Butternut squash||1 cup, cubes||582|
|White beans, cooked||½ cup||500|
|Banana||1 medium (7” to 7 7/8”)||422|
|Plain low-fat yogurt||1 6-oz container||398|
|Dried apricots||¼ cup||378|
|Chicken breast, no skin||3 oz||295|
|Cashews||1 oz (about 18 cashews)||179|
|Spinach, raw||1 cup||140|
|Coffee, unsweetened||8 oz||118|
|Black tea||8 oz||89|
Table Source: U.S. Department of Agriculture, Agricultural Research Service. FoodData Central, 2019. Accessed August 20, 2019.
This article is written by Allison Webster, PhD, RD, with contributions from IFIC intern, Yasaman Salahmand.