Potassium is excellent for heart health. A randomized double-blind trial published in the January 2010 issue of the journal “Hypertension" studied the effects of potassium supplementation on cardiovascular risk factors, endothelial function and bone turnover in people with mild hypertension. In the study, participants who took potassium bicarbonate for 12 weeks achieved a significant decrease in stiffness of large elastic arteries, improvement in left ventricular diastolic function and endothelial function, and reduction in left ventricular mass.
“Potassium is vasoactive; when infused into the arterial supply of a vascular bed, blood flow increases.” It has been reported that potassium depletion in normal humans increases blood pressure, as well as reducing the ability to deal with an acute sodium load and sodium retention.8 In borderline hypertensives (140/90), “a low-potassium diet (16 mmol/day) for 10 days increases systolic and diastolic pressures by 7 and 6 mmHg, respectively, relative to 10 days on a high-potassium diet (96 mmol/day).” Indeed, potassium supplementation lowers blood pressure in established hypertension.
 Sudhir et al. Reduced dietary potassium reversibly enhances vasopressor response to stress in African Americans. Hypertension 29:1083-90 (1997).