What Is Potassium Good for in the Body?

Bananas are a good source of potassium.
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Potassium is an electrolyte and a mineral found in the body that is responsible for regulating many chemical processes. Potassium helps muscles contract, regulates the body's fluid balance and maintains blood pressure. The Institute of Medicine recommends that adults consume at least 4,700 milligrams of potassium every day.


    Potassium is found in most foods but primarily in fruits and vegetables. The highest source of potassium comes from potatoes. One small baked potato contains 738 milligrams of potassium, which is more than 15 percent of the daily intake for adults. Other good sources include beans, milk, yogurt, soy milk, orange juice, bananas, apricots, tomatoes, spinach, sweet potatoes and fish such as halibut and cod.

Blood Pressure

    Potassium counters the effects of sodium on blood pressure. According to the American Heart Association, the more potassium you consume, the more sodium your kidneys expel through your urine. Potassium also helps blood vessels relax, which in turn lowers blood pressure. A diet low in potassium and high in sodium may be a risk factor for high blood pressure.

Muscle Contraction

    A lack of potassium, which can be caused by dehydration, may lead to muscle cramps and spasms. A low potassium level in the blood can also affect the muscles of the heart and cause irregular rhythms. For this reason, it is important to stay hydrated -- especially when you are exercising -- by replacing lost electrolytes. The use of diuretics in the form of some medications can also cause an excess loss of potassium from the body. Consult with your doctor regarding the need for potassium supplementation if you are taking diuretic medications,

Fluid Balance

    Potassium, in conjunction with sodium, helps keep the water inside and outside of your cells in the correct proportion. The concentration of potassium within the body is directly related to the concentration of sodium. When sodium levels rise, potassium levels drop. Conversely, when sodium levels drop, potassium levels rise. This process is regulated by the kidneys to keep the concentrations of potassium and sodium in balance. The amount of potassium within the body can be affected by how well your kidneys are working, as well as hormones, vomiting, diarrhea, potassium within food and potassium supplements. Symptoms of potassium imbalance include muscle cramps or weakness, dehydration, low blood pressure, confusion, irritability, paralysis and changes in heart rhythms.

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