Potassium plays a part in almost everything inside your body, including your heart, kidneys, muscles, and nerves. It also may help protect against stroke, high blood pressure, and osteoporosis. Many Americans don’t get enough. Dried apricots, bananas, spinach, milk, and yogurt are good sources. Ask your doctor before you take supplements. They can interfere with medications for high blood pressure, migraine, and other conditions.