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Cardiovascular benefits associated with higher dietary K+ versus lower dietary Na+: Evidence from population and mechanistic studies

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AJP Endocrinology and Metabolism

Published online on

Abstract

The WHO ranks hypertension the leading global risk factor for disease, specifically, cardiovascular disease. Blood pressure is higher in westernized populations consuming sodium-rich processed foods compared to isolated societies consuming potassium-rich natural foods. Evidence suggests that lowering dietary Na+ is particularly beneficial in hypertensives 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 blood pressure regardless of sodium intake. Interventional studies with potassium supplementation suggest 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 potassium benefit: the distal tubule Na+- Cl- cotransporter (NCC) controls Na+ delivery downstream to the collecting duct where Na+ reabsorbed by epithelial Na+ channels (ENaC) drives K+ secretion and excretion through K+ channels in the same region. High dietary K+ provokes a decrease in the 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+. Taken together, the findings suggest that public health efforts directed towards increasing consumption of natural potassium rich foods would reduce blood pressure and, thus, cardiovascular and kidney disease.