Long-term potassium supplementation lowers blood pressure in elderly hypertensive subjects.

Following a randomised cross-over trial of the effect of a four-week 60 mmol/day potassium supplement versus placebo on blood pressure (BP), eight of the original 18 hypertensive subjects continued with a 48 mmol daily potassium supplement for four months. For these eight subjects 24-h potassium excretion during placebo, one month of 60 mmol and four months of 48 mmol daily potassium supplementation phases was 56 +/- 23, 102 +/- 28 and 90 +/- 35 mmol/24 hours, respectively, and mean 24-h BP following each phase was 160 +/- 16/89 +/- 11, 147 +/- 13/83 +/- 12 and 145 +/- 14/81+/- 9 mmHg respectively, a significant fall in mean 24-h SBP between four months of potassium supplement and placebo period of 15 +/- 13 mmHg (95% CI: 4, 26 mmHg, p = 0.02), although the fall in 24-h DBP was not significant (8 +/- 11 mmHg, 95% CI: 0, 17 mmHg, p = 0.08). Modest increases in dietary potassium intake could have significant effects on lowering BP in the large proportion of elderly subjects with hypertension.