Integration of the response to a dietary potassium load: a paleolithic perspective

Our purpose is to integrate new insights in potassium (K+) physiology to understand K+ homeostasis and illustrate some of their clinical implications. Since control mechanisms that are essential for survival were likely developed in Paleolithic times, we think the physiology of K+ homeostasis can be better revealed when viewed from what was required to avoid threats and achieve balance in Paleolithic times. Three issues will be highlighted. First, we shall consider the integrative physiology of the gastrointestinal tract and the role of lactic acid released from enterocytes following absorption of sugars (fruit and berries) to cause a shift of this K+ load into the liver. Second, we shall discuss the integrative physiology of WNK kinases and modulation of delivery of bicarbonate to the distal nephron to switch the aldosterone response from sodium chloride retention to K+ secretion when faced with a K+ load. Third, we shall emphasize the role of intra-renal recycling of urea in achieving K+ homeostasis when the diet contains protein and K+.