This mineral is important for a healthy nervous system and a regular heart  rhythm. It helps prevent stroke, aids in proper muscle contraction, and works with sodium to control the body's water balance. Potassium is important for chemical reactions within the cells and aids in maintaining stable blood pressure and in transmitting electrochemical impulses. A 1997 review of earlier studies showed that low potassium intake might be a significant factor in the development of high blood pressure. A high intake of potassium protects several body systems, including cardiovascular, kidney and bone. Potassium also regulates the transfer of nutrients through cell membranes. This function of potassium has been shown to decrease with age, which may account for some of the circulatory damage, lethargy and weakness experienced by older people. Together with magnesium, potassium can help prevent calcium-oxalate kidney stones. 

Signs of potassium deficiency include abnormally dry skin, acne, chills,  cognitive impairment, constipation, diarrhea, diminished  reflex function, edema, nervousness, insatiable thirst, fluctuations in heartbeat, glucose intolerance, growth impairment, high cholesterol levels, insomnia, low blood pressure, muscular fatigue and weakness, nausea and vomiting, periodic headaches, proteinuria (protein in the urine), respiratory distress, and salt retention.