Abstract
Potassium is one of the most important elements of human organism. Its main distribution in the intracellular space makes it an essential component of intracellular volume regulation on the other hand extracellular/ intracellular potassium ratio determines the resting membrane potential. This later capability of potassium makes essential the necessity of maintaining extracellular potassium levels in a narrow range limit between 3.5 and 5.5 mEq/L in order to avoid dangerous dysfunction of excitable cells such as myocardium, neuronal cells and muscle cells. Because of asymmetric potassium distribution between intracellular and extracellular space there is a continuous need to excrete the excess of potassium ingested by food in a diurnal basis. The main site of potassium excretion is the distal nephron and it is coupled directly with the amount of sodium and solute delivered to this segment of the nephron. Although the very early segment of distal convoluted tubule has no ability to excrete potassium it is capable to regulate the amount of sodium chloride delivered downstream the nephron and by this way is implicated indirectly in potassium excretion. Newer data suggest that this segment of the nephron responds to increased extracellular levels of potassium by reducing sodium chloride cotransporter activity and so increases sodium delivery to distal nephron for exchange with potassium and leads to kaliuresis as well as natriuresis. It is believed that this mechanism is responsible for the beneficial effect of increased potassium intake in ameliorating hypertension even in cases of increased salt intake. In this review article, under the light of recent discoveries, we try to elucidate the complex underlying mechanisms of increased potassium intake and blood pressure regulation as well as the possible beneficial effect of Paleolithic diet upon hypertension.