K ⁺ and the renin–angiotensin–aldosterone system: new insights into their role in blood pressure control and hypertension treatment

Approximately 25% of the adult population is diagnosed with hypertension and it is therefore one of the biggest challenges for the health sector. The renin–angiotensin–aldosterone system (RAAS) adjusts effective circulating volume and ultimately blood pressure (BP). Accordingly, antihypertensive drugs targeting the RAAS have been a major focus in modern medical treatment. Low and high dietary K + intakes are associated with increased or decreased BP and risk of cardiac failure, respectively, suggesting that dietary K + augmentation has the potential to supplement or replace conventional anti‐hypertensive drugs. Animal studies have indicated that the beneficial effects of high dietary K + may be linked to a dominant regulatory role of plasma K + on key renal transport proteins controlled by the RAAS. However, only a limited number of studies have investigated whether the reported mechanisms in animal models apply to humans. Furthermore, hypertension is often treated with so‐called ‘K + sparing’ drugs, thus complicating co‐treatment with K + supplementation. In this review, we revisit old concepts of RAAS effects in the kidney, relate them to effects of dietary K + manipulation, and finally consider the clinical potential of treating hypertension with K + supplementation alone or in combination with RAAS inhibitors. Collectively, a wealth of data suggest that increased dietary K + intake may have beneficial effects on BP in the general population, but underlying medical conditions or current treatment regimens need to be carefully considered before implementing K + supplementation in patients.