Potassium is an element represented by the symbol “K” on the periodic table. Technically considered an alkali metal, potassium has very similar chemical properties to sodium. However, they have very different effects in the human body. Understanding the physiological role of potassium can motivate you to get enough of this beneficial nutrient in your diet.
What Is Potassium?
Potassium is a dietary mineral that acts as an electrolyte in the body. Electrolytes dissociate into charged particles, or ions, when they are in a solution. This means that potassium carries an electrical charge, making it important for activities such as muscle contraction and maintaining pH balance (Martin, 2015). The body regulates potassium levels very carefully by shifting potassium in and out of cells because too much potassium (hyperkalemia) or too little calcium (hypokalemia) can cause serious health problems (Palmer, 2014).
Physiological Role of Potassium
Potassium plays dozens of roles throughout the body. One of its most important roles is maintaining a cell’s membrane potential. A cell’s membrane potential refers to its electrical and chemical properties that form the basis for muscle contraction, nerve cell signalling, and heart functioning (Lin, 2010). A special membrane pump called the sodium potassium pump pulls two potassium ions into the cell for every three sodium ions pushed out of the cell. This process maintains the membrane potential, sustaining a cell’s life.
Because of this critical role for potassium, failure to get enough of this mineral is associated with several diseases. Low potassium intake may contribute to risk for osteoporosis, cardiovascular disease, stroke, kidney stones, and high blood pressure (Lin, 2010).
Recommended Daily Intake of Potassium
The Food and Nutrition Center of the Institute of Medicine sets target guidelines for Americans’ daily intake of potassium. Healthy men and women should aim to get 4,700 milligrams of potassium each day (Chen, 2014). For breastfeeding women, this target rises to 5,100 milligrams daily. It’s also important to note that those with kidney problems may need to be on a potassium restricted diet and would work with their doctor and registered dietitian on an eating plan that is right for them (Chen, 2014).
The average daily potassium intake is just 2,640 mg, significantly lower than the recommended target of 4,700 mg (Hoy & Goldman, 2012). Research suggests that intake of potassium can reduce the adverse effects of high sodium intake on blood pressure and that a low potassium intake may be one factor that contributes to the development of high blood pressure.
Low potassium levels is a condition called hypokalemia. Some causes of hypokalemia include: diuretics (water pills) to treat high blood pressure or heart failure, excessive laxative intake, severe or prolonged vomiting and diarrhea, certain kidney or adrenal gland disorders.. Hypokalemia may lead to muscle weakness, intestinal problems, abdominal pain, fatigue, and abnormal heartbeat.
Although it is possible to get too much potassium, a condition known as hyperkalemia, this is typically only seen in people with kidney failure or hormonal problems (Lin, 2010).