The role of potassium in stroke, cardiovascular disease, and hypertension

Abstract

Dietary potassium reduces the incidence of cerebrovascular accident (CVA) not only by lowering blood pressure (BP) directly, but also through BP-independent mechanisms. Dietary potassium intake has been demonstrated to significantly lower BP in a dose-responsive manner in both hypertensive and nonhypertensive patients in observational studies, clinical trials, and several metaanalyses. In hypertensive patients, the linear dose-response relationship is a 1.0-mmHg reduction in systolic BP and a 0.52-mmHg reduction in diastolic BP per 0.6 g/day increase in dietary potassium intake that is independent of baseline potassium deficiency. The average reduction in BP on 4.7 g (120 mmol) of dietary potassium per day is 8.0/4.1 mmHg depending on race, pretreatment BP, gender, cormorbid conditions, type of potassium used, exercise level, duration of use, and the relative intakes of other minerals, such as sodium, magnesium, and calcium. If the dietary sodium chloride intake is high in the presence of increased dietary potassium, the BP reduction is more prominent. Blacks have a greater decrease in BP compared to Caucasians with an equal potassium intake. Potassium-induced reduction in BP significantly lowers the incidence of CVAs, coronary heart disease, myocardial infarction (MI), cardiac arrhythmias, sudden death, renal disease, proteinuria, hyperglycemia, left ventricular hypertrophy, diastolic dysfunction, and other cardiovascular diseases (CVDs). However, potassium also reduces the risk of CVA independent of the decrease in BP. Some of the proposed mechanisms for CVA reduction independent of the BP include improved endothelial dysfunction with vasodilation, increased vascular nitric oxide, reduction in asymmetric dimethyl arginine, decreased vascular intracellular calcium and sodium, alteration in DNA synthesis and proliferation in the cerebral vascular smooth muscle, decrease in vascular neointimal formation, decrease in TGB-beta, lower thrombosis risk, reduction in oxidative stress and NADPH oxidase, and decrease in vascular inflammation. Increasing the consumption of potassium to 4.7 g/day predicts lower event rates for future CVDs with estimated decreases in CVAs of 8-15% and myocardial infarction of 6-11%.