Objective: To determine whether an increase in dietary potassium intake from natural foods reduces the need for antihypertensive medication in patients with essential hypertension.
Design: Randomized, controlled trial with 1-year follow-up.
Setting: Hypertension outpatient clinic of a university hospital.
Patients: Fifty-four patients with well-controlled hypertension, 47 of whom completed 1 year of follow-up.
Intervention: Patients were randomly assigned to one of two groups and were given dietary advice aimed at selectively increasing potassium intake (group 1) or at keeping their customary diet unchanged (group 2). During a 1-year follow-up period, drug therapy was reduced in stepwise fashion, according to a fixed protocol, provided that blood pressure remained below 160/95 mm Hg.
Main results: Potassium intake was checked monthly by referring to 3-day food records and by measuring 24-hour urinary potassium excretion. Potassium intake increased in group 1 but did not change in group 2 (P less than 0.001). No change was observed in either urinary sodium excretion or in body weight. After 1 year, the average drug consumption (number of pills per day) relative to that at baseline was 24% in group 1 (95% Cl, 15% to 32%) and 60% in group 2 (Cl, 44% to 76%) (P less than 0.001). By the end of the study, blood pressure could be controlled using less than 50% of the initial therapy in 81% of the patients in group 1 (Cl, 66% to 96%) compared with 29% of the patients in group 2 (Cl, 10% to 48%) (P = 0.001). Patients in group 1 ended the study with a lower number of reported symptoms compared with patients in the control group (P less than 0.001).
Conclusion: Increasing the dietary potassium intake from natural foods is a feasible and effective measure to reduce antihypertensive drug treatment.