Potassium is an essential mineral micronutrient in human nutrition and is necessary for the function of all living cells. It plays a critical role in brain and nerve function and in influencing the fluid and electrolyte balance in the body (through the so-called Na+/K+-ATPase pump). Potassium is also important in preventing muscle contraction and in sending nerve impulses.

Potassium deficiency often results in muscle weakness, heart disease, decreased reflex response, depression, alcohol abuse, and in severe cases respiratory paralysis, alkalosis and cardiac arrhythmia. A shortage of potassium in body fluids may cause a potentially fatal condition known as hypokalemia, typically resulting from diarrhea, increased diuresis and vomiting. Diets high in potassium can reduce the risk of hypertension and possibly stroke.

Individuals suffering from kidney diseases may suffer adverse health effects from consuming large quantities of dietary potassium – as potassium excretion is controlled by the kidneys and buildup of blood concentrations of potassium may trigger fatal cardiac arrhythmia. Patients with acute celiac disease show a significant rise in potassium levels.

Potassium deficiency is rare in individuals eating a balanced diet. However, most Americans consume only half the amount of potassium recommended by the Institute of Medicine. Studies have also found that insufficient potassium intake is common in the European Union (Particularly Germany and Italy).

Foods high in potassium include orange juice, potatoes, bananas, avocados, tomatoes, broccoli, soybeans, brown rice, garlic and apricots, although it is found to some degree in most fruits, vegetables and meats.