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.
- dietary sodium
- dietary potassium
- Copyright © 2017, American Journal of Physiology-Endocrinology and Metabolism