Aggressive increase in dietary potassium does not cause hyperkalemia in medicated hypertensive individuals

BACKGROUND: A high potassium diet decreases blood pressure. As such, the Canadian Hypertension Education Program recommends a diet rich in high potassium food sources such as fruits and vegetables. However, the safety of increasing dietary potassium for individuals on antihypertensive medical therapy, including drugs that antagonize the renin-angiotensin-aldosterone system (RAAS), has not been described. This is important as RAAS blockade may predispose to hyperkalemia. The purpose of this study was to assess the impact of increasing dietary potassium intake on serum potassium in medicated hypertensive individuals. METHODS: We conducted an open controlled clinical trial in 20 hypertensive subjects with normal renal function who were randomized to a usual diet group (UD n=10), or a high potassium diet group (HPD, n= 10). Fruits and vegetables were used to increase potassium intake. All participants were on stable hypertension therapy including RAAS blocking drugs in 7 participants in the UD group, and 9 in the HPD group. Serum potassium concentration and food records were completed at baseline, week 2, and at the end of the 4-week study. 24 Hour urine collections were completed at baseline and at 4 weeks. Differences were tested using 2-way repeated measures ANOVA. RESULTS: In the HPD group, dietary potassium intake was 3744 ± 1077 (SD) mg/d at baseline, 5151 ± 929 mg/d at week 2 (p<0.001 versus baseline and UD), and 5654 ± 1067 mg/d at week 4 (p<0.001 versus baseline and UD), and there was a 51 ± 12.4 percent increase in urinary potassium excretion at week 4 (p < 0.001). In the HPD group, serum potassium was 3.9 ± 0.6 mmol/L at baseline, 4.3 ± 0.4 mmol/L at week 2 (p<0.04 versus baseline) and 4.1 ± 0.4 mmol/L at week 4 (p= 0.13 versus baseline). The highest recorded serum potassium level was 4.8; there was no hyperkalemia. No changes were observed in the UD group. CONCLUSION: This study demonstrated that an aggressive increase in dietary potassium in medicated hypertensive individuals resulted in transient rises in serum potassium, but no hyperkalemia. This provides safety data in support of dietary strategies in medicated hypertensive individuals.