Potassium with sodium, helps regulate body's fluid balance. Bananas is not the only source of potassium other good dietary sources we have citrus fruits, dried fruits, potatoes, water in some areas. Signs of deficiency of potassium is bad includes muscle weakness, cardiac arrhythmia and irritability. For Signs of overdose includes nausea, diarrhea, and also cardiac arrhythmia.
"So eat in balance not to little and not to much"