Exactly what does potassium do for the body? If you've ever participated in sports or gotten really serious about working out, you've probably had a coach or personal trainer tell you that it's a good idea to eat a banana after your workouts because the potassium will prevent muscle cramping. In addition to being an essential mineral, potassium is a electrolyte, or a substance that has the ability to conduct electricity within the human body.
Potassium as an Electrolyte
Potassium's importance as an electrolyte stems from its ability to disassociate into ions, or charged particles, in solution, which makes it capable of conducting electricity. While potassium exists both inside and outside cell walls, the concentration of potassium inside cell walls is 30 times higher than it is outside. Sodium, on the other hand, is 10 times as concentrated outside cell walls as inside. Potassium is the principle source of cations, or positively charged ions, within cells, and sodium is the principle source of cations outside cell walls. Together, potassium and sodium ions work to produce an electrochemical gradient across the cell wall, or a membrane potential, that is used to pump sodium out of a cells and replace it with potassium. This exchange is necessary for proper nerve function and muscle contraction.
Potassium and Your Health
A study that looked at the dietary potassium consumption of 4700 men for eight years found that men with relatively high potassium intakes, around 4300 mg per day, were 38 percent less likely to suffer a stroke compared to men who consumed only 2300 mg of potassium per day. Potassium intake is also thought to prevent bone loss that can lead to osteoporosis. Because high potassium intake is linked to lower rates of calcium excretion, potassium is thought to protect against kidney stones. A study that looked at the potassium intake of 45,000 men for four years found that men who consumed more than 4042 mg of potassium per day were half as likely to develop kidney stones as men who consumed less than 2895 mg of potassium per day. Diets high in potassium are also thought to help prevent, or even treat, hypertension. Symptoms of hypokalemia, or clinical potassium deficiency, include nausea or vomiting, personality or mood changes, muscle weakness, and irregular heartbeat.