Maintaining K balance on the low-Na, high-K diet.

A low-Na, high-K diet (LNaHK) is considered a healthier alternative to the "Western" high-Na diet. Because the mechanism for K secretion involves Na reabsorptive exchange for secreted K in the distal nephron, it is not understood how K is eliminated with such low Na intake. Animals on a LNaHK diet produce an alkaline load, high urinary flows, and markedly elevated plasma ANG II and aldosterone levels to maintain their K balance. Recent studies have revealed a potential mechanism involving the actions of alkalosis, urinary flow, elevated ANG II, and aldosterone on two types of K channels, renal outer medullary K and large-conductance K channels, located in principal and intercalated cells. Here, we review these recent advances.