Potassium is an essential mineral that is needed by all tissues in the body. It is sometimes referred to as an electrolyte because it carries a small electrical charge that activates various cell and nerve functions. Potassium is found naturally in many foods and as a supplement. Its main role in the body is to help maintain normal levels of fluid inside our cells. Sodium, its counterpart, maintains normal fluid levels outside of cells. Potassium also helps muscles to contract and supports normal blood pressure.
The U.S. Dietary Reference Intakes state that there is not enough evidence to establish a Recommended Dietary Allowance (RDA) for potassium. However, the National Academy of Medicine has established an Adequate Intake (AI) for potassium. 
- For women 14-18 years of age, the AI is 2,300 mg daily; for women 19+, 2,600 mg. For pregnant and lactating women, the AI ranges from 2,500-2,900 depending on age.
- For men 14-18 years of age, the AI is 3,000 mg; for men 19+, 3,400 mg.
It is estimated that the average daily intake of potassium in adults is about 2,320 mg for women and 3,016 mg for men. 
Potassium and Health
The functions of sodium and potassium in the body are closely related and often studied together.
Potassium is widely available in many foods, especially fruits and vegetables. Leafy greens, beans, nuts, dairy foods, and starchy vegetables like winter squash are rich sources.
- Dried fruits (raisins, apricots)
- Beans, lentils
- Winter squash (acorn, butternut)
- Spinach, broccoli
- Beet greens
- Oranges, orange juice
- Coconut water
- Dairy and plant milks (soy, almond)
- Cashews, almonds
Signs of Deficiency and Toxicity
The kidneys work to maintain normal blood levels of potassium by flushing out excess amounts through urine. Potassium can also be lost through stool and sweat. At least 400-800 mg daily from food is needed because of normal daily losses. Any conditions that increase fluid losses beyond normal such as vomiting, diarrhea, and certain medications like diuretics can lead to a deficiency, called hypokalemia. Hypokalemia is most common in hospitalized patients who are taking medications that cause the body to excrete too much potassium. It is also seen in people with inflammatory bowel diseases (Crohn’s disease, ulcerative colitis) that may cause diarrhea and malabsorption of nutrients.
It is rare for a potassium deficiency to be caused by too low a food intake alone because it is found in so many foods; however an inadequate intake combined with heavy sweating, diuretic use, laxative abuse, or severe nausea and vomiting can quickly lead to hypokalemia. Another reason is a deficiency of magnesium, as the kidneys need magnesium to help reabsorb potassium and maintain normal levels in cells.
- Muscle cramps or weakness
- Muscle paralysis and irregular heart rate (with severe hypokalemia)
Too much potassium in the blood is called hyperkalemia. In healthy people the kidneys will efficiently remove extra potassium, mainly through the urine. However, certain situations can lead to hyperkalemia: advanced kidney disease, taking medications that hold onto potassium in the body (including NSAIDs), or people who have compromised kidneys who eat a high-potassium diet (more than 4,700 mg daily) or use potassium-based salt substitutes. Symptoms of hyperkalemia:
- Weakness, fatigue
- Nausea, vomiting
- Shortness of breath
- Chest pain
- Heart palpitations, irregular heart rate
Did You Know?
- The chemical symbol for potassium is “K,” not to be confused with vitamin K.
- Salt substitutes are sometimes made from potassium chloride, which replaces some or all of the sodium chloride in table salt. Although those on salt-restricted diets may benefit from its much lower sodium content, potassium salt has a bitter aftertaste when heated so it is not recommended for cooking. Check with your doctor before trying a potassium salt, because extra potassium can be dangerous for people who have trouble eliminating excess amounts or who are taking medications that can increase potassium levels in the bloodstream.
Vitamins and Minerals
Last reviewed March 2023
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