F L Brancati1, L J Appel, A J Seidler, P K Whelton. 1. Welch Center for Prevention, Epidemiology, & Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Md., USA.
Abstract
OBJECTIVE: To determine the effect of potassium supplementation on blood pressure in African Americans consuming a low-potassium diet. DESIGN: Randomized, double-blind, placebo-controlled trial with two parallel arms. SETTING: Community-based research site. PARTICIPANTS: Eighty-seven healthy African Americans aged 27 to 65 years with a systolic blood pressure between 100 and 159 mm Hg and a diastolic blood pressure between 70 and 94 mmHg. INTERVENTION: During the 21-day intervention period, all participants were provided with a low-potassium diet (32 to 35 mmol/d). In addition to this diet, they were randomly assigned to receive either potassium supplements (80 mmol/d) or placebo. MAIN OUTCOME MEASURE: Change in blood pressure in the potassium vs the placebo group, based on a total of nine blood pressure readings at three visits. Blood pressures were taken before and during the intervention by means of random-zero sphygmomanometry. RESULTS: At baseline, the placebo and potassium groups were similar for mean blood pressure (127/78 vs 125/77 mm Hg), 24-hour urinary potassium excretion (50 vs 44 mmol), and all other variables measured (all P > .05). During the intervention, the net difference in 24-hour urinary potassium excretion between groups was 70 mmol. Compared with the placebo group, the potassium supplementation group experienced a net decline in systolic blood pressure of 6.9 mm Hg (95% confidence interval, -9.3 to -4.4 mm Hg; P < .001) and a decline in diastolic blood pressure of 2.5 mm Hg (95% confidence interval, -4.3 to -0.8 mm Hg; P = .004). Simultaneous adjustment for differences in baseline characteristics only strengthened these estimates. CONCLUSIONS:Potassium supplementation reduces blood pressure substantially in African Americans consuming a diet low in potassium. Increased potassium intake may play an important role in reducing blood pressure in this population at high risk for hypertension.
RCT Entities:
OBJECTIVE: To determine the effect of potassium supplementation on blood pressure in African Americans consuming a low-potassium diet. DESIGN: Randomized, double-blind, placebo-controlled trial with two parallel arms. SETTING: Community-based research site. PARTICIPANTS: Eighty-seven healthy African Americans aged 27 to 65 years with a systolic blood pressure between 100 and 159 mm Hg and a diastolic blood pressure between 70 and 94 mm Hg. INTERVENTION: During the 21-day intervention period, all participants were provided with a low-potassium diet (32 to 35 mmol/d). In addition to this diet, they were randomly assigned to receive either potassium supplements (80 mmol/d) or placebo. MAIN OUTCOME MEASURE: Change in blood pressure in the potassium vs the placebo group, based on a total of nine blood pressure readings at three visits. Blood pressures were taken before and during the intervention by means of random-zero sphygmomanometry. RESULTS: At baseline, the placebo and potassium groups were similar for mean blood pressure (127/78 vs 125/77 mm Hg), 24-hour urinary potassium excretion (50 vs 44 mmol), and all other variables measured (all P > .05). During the intervention, the net difference in 24-hour urinary potassium excretion between groups was 70 mmol. Compared with the placebo group, the potassium supplementation group experienced a net decline in systolic blood pressure of 6.9 mm Hg (95% confidence interval, -9.3 to -4.4 mm Hg; P < .001) and a decline in diastolic blood pressure of 2.5 mm Hg (95% confidence interval, -4.3 to -0.8 mm Hg; P = .004). Simultaneous adjustment for differences in baseline characteristics only strengthened these estimates. CONCLUSIONS:Potassium supplementation reduces blood pressure substantially in African Americans consuming a diet low in potassium. Increased potassium intake may play an important role in reducing blood pressure in this population at high risk for hypertension.
Authors: Lisa A Cooper; L Ebony Boulware; Edgar R Miller; Sherita Hill Golden; Kathryn A Carson; Gary Noronha; Mary Margaret Huizinga; Debra L Roter; Hsin-Chieh Yeh; Lee R Bone; David M Levine; Felicia Hill-Briggs; Jeanne Charleston; Miyong Kim; Nae-Yuh Wang; Hanan Aboumatar; Jennifer P Halbert; Patti L Ephraim; Frederick L Brancati Journal: Am J Public Health Date: 2013-09-12 Impact factor: 9.308