There s growing evidence that the more potassium you get in your diet, the less likely you are to develop high blood pressure. One reason for this probably has to do with potassium s interaction with sodium , says David B. Young, Ph.D., professor of physiology and biophysics at the University of Mississippi Medical Center in Jackson. Think of sodium as a water magnet. Excreting water reduces your blood volume, which in turn reduces your blood pressure. Thus, potassium achieves the same goal as a diuretic.
Potassium also inhibits the release of a hormone called renin from the kidneys.
Renin activates another hormone, called angiotensin, which throws the switch on a kind of internal suction pump. When angioten-sin is activated, your blood vessels constrict and your kidneys start to retain sodium . Both of these actions bump up blood pressure. In fact, that s the approach that some doctors take. Excessive potassium can upset the balance of other minerals in the body and cause potentially fatal heart and kidney problems.