Potassium is a vital mineral for the human body. It is extremely important for the function of the heart, kidneys and other organs. Most people who do not eat healthy food, should take extra potassium. The most common cause of deficiency of calcium is the consumption of highly refined foods that are low in nutrients. Low levels of potassium are associated with high blood pressure, heart disease, stroke, arthritis, cancer, digestive problems and infertility.