 Taken together, there is reliable evidence for an inverse correlation between potassium intake and the level of blood pressure. Nevertheless the mechanism behind this apparent inverse correlation is still a conundrum. Different hypothesis has been developed, mostly on the basis of animal studies. In the rat kidney, potassium depletion is expected to elicit retention of sodium and thereby hypertension. At the level of the arterial wall potassium depletion is expected to lower the intracellular potassium level in smooth muscle cells, which would lead to a depolarization of the membrane and thereby elicit contraction, increased peripheral vascular resistance and hypertension. On the other hand a high potassium diet is expected to elicit an endothelium-dependent vasodilatation. Another postulated mechanism is that high potassium levels in the cerebrospinal fluid would decrease the sympathetic outflow from the brain and thereby blood pressure. The mentioned theories 11 are mainly based on animal studies. 