Cardiovascular benefits associated with higher dietary K+ vs. lower dietary Na+: evidence from population and mechanistic studies

Abstract

<p class="first" id="d12266778e156">The World Health Organization ranks hypertension the leading global risk factor for disease, specifically, cardiovascular disease. Blood pressure (BP) is higher in Westernized populations consuming Na ⁺-rich processed foods than in isolated societies consuming K ⁺-rich natural foods. Evidence suggests that lowering dietary Na ⁺ is particularly beneficial in hypertensive individuals who consume a high-Na ⁺ diet. Nonetheless, numerous population studies demonstrate a relationship between higher dietary K ⁺, estimated from urinary excretion or dietary recall, and lower BP, regardless of Na ⁺ intake. Interventional studies with K ⁺ supplementation suggest that it provides a direct benefit; K ⁺ may also be a marker for other beneficial components of a “natural” diet. Recent studies in rodent models indicate mechanisms for the K ⁺ benefit: the distal tubule Na ⁺-Cl ⁻ cotransporter (NCC) controls Na ⁺ delivery downstream to the collecting duct, where Na ⁺ reabsorbed by epithelial Na ⁺ channels drives K ⁺ secretion and excretion through K ⁺ channels in the same region. High dietary K ⁺ provokes a decrease in NCC activity to drive more K ⁺ secretion (and Na ⁺ excretion, analogous to the actions of a thiazide diuretic) whether Na ⁺ intake is high or low; low dietary K ⁺ provokes an increase in NCC activity and Na ⁺ retention, also independent of dietary Na ⁺. Together, the findings suggest that public health efforts directed toward increasing consumption of K ⁺-rich natural foods would reduce BP and, thus, cardiovascular and kidney disease. </p>