This, combined with other obligatory losses, suggests that potassium balance cannot be achieved with intakes less than about 400вЂ“800 mg/day. The kidneys can adapt to variable potassium intakes in healthy individuals, but a minimum of 5 mmol (about 195 mg) potassium is excreted daily in urine. The kidneys control potassium excretion in response to changes in dietary intakes, and potassium excretion increases rapidly in healthy people after potassium consumption, unless body stores are depleted. Potassium is excreted primarily in the urine, some is excreted in the stool, and a very small amount is lost in sweat. About 90% of ingested potassium is absorbed and used to maintain its normal intracellular and extracellular concentrations. Potassium is absorbed via passive diffusion, primarily in the small intestine. In addition to maintaining cellular tonicity, this gradient is required for proper nerve transmission, muscle contraction, and kidney function. The intracellular concentration of potassium is about 30 times higher than the extracellular concentration, and this difference forms a transmembrane electrochemical gradient that is maintained via the sodium-potassium (Na+/K+) ATPase transporter. Most potassium resides intracellularly, and a small amount is in extracellular fluid. The total amount of potassium in the adult body is about 45 millimole (mmol)/kg body weight (about 140 g for a 175 pound adult 1 mmol = 1 milliequivalent or 39.1 mg potassium). Potassium has a strong relationship with sodium, the main regulator of extracellular fluid volume, including plasma volume. Potassium is present in all body tissues and is required for normal cell function because of its role in maintaining intracellular fluid volume and transmembrane electrochemical gradients. Potassium, the most abundant intracellular cation, is an essential nutrient that is naturally present in many foods and available as a dietary supplement.

For a reader-friendly overview of Potassium, see our consumer fact sheet on Potassium. This is a fact sheet intended for health professionals.

Potassium element