Potassium

Potassium is the main mineral found inside cells (an intracellular electrolyte) at a concentration that is 30 times greater than the concentration of potassium found outside cells. It is involved in water balance, nerve impulse transmission, and muscular contractions. Dietary deficiency is rare and typically occurs only with chronic diarrhea and vomiting or laxative abuse. Individuals taking medications for high blood pressure force the loss of sodium, and in this process potassium is also lost. These individuals are encouraged to replace this lost potassium through the intake of potassium supplements or foods high in potassium (fruits, vegetables, and meats). Typical intakes of potassium range from 1,000 to 11,000 milligrams per day (1 to 11 grams per day); people consuming large amounts of fresh fruits and vegetables have the highest intakes.

There is evidence that a potassium intake of about 3,500 milligrams per day is useful in controlling high blood pressure. Adequate intakes of potassium help counteract the impact of excess sodium intake, thereby helping to control high blood pressure. It also reduces the risk of developing a lower bone density and lowers the risk of developing kidney stones. The DRI for potassium is 4.7 grams per day for both adult men and women. Although there is no established safe upper limit, potassium toxicity appears to develop with an intake of approximately 18 grams and may lead to cardiac arrest. People with chronic renal disease or diabetes appear to be at particular risk of death from hyperkalemia, most often resulting from high intake of salt substitutes or potassium supplements. Because of the risk of sudden cardiac arrest with an excess potassium intake, potassium supplementation is generally not recommended.

It is well established that potassium is critical for heart and skeletal muscle function. However, the relatively small amount of potassium lost in sweat does not seriously affect body stores, so it does not typically have an impact on athletic performance in well-nourished athletes.