Effect of short-term supplementation of potassium chloride and potassium citrate on blood pressure in hypertensives.

Randomized trials have shown that increasing potassium intake lowers blood pressure. However, most previous trials used potassium chloride, whereas potassium in fruits and vegetables is not a chloride salt. It is unclear whether a nonchloride salt of potassium has a greater or lesser effect on blood pressure compared with potassium chloride. We performed a randomized crossover trial comparing potassium chloride with potassium citrate (96 mmol/d, each for 1 week) in 14 hypertensive individuals. At baseline, blood pressure was 151+/-16/93+/-7 mm Hg with a 24-hour urinary potassium of 81+/-24 mmol. During the randomized crossover part of the study, blood pressure was 140+/-12/88+/-7 mm Hg with potassium chloride (24-hour urinary potassium: 164+/-36 mmol) and 138+/-12/88+/-6 mm Hg with potassium citrate (24-hour urinary potassium: 160+/-33 mmol). These blood pressures were significantly lower compared with that at baseline; however, there was no significant difference in blood pressure between potassium chloride and potassium citrate, mean difference (95% confidence interval): 1.6 (-2.3 to 5.6) mm Hg for systolic and 0.6 (-2.4 to 3.7) mm Hg for diastolic. Our results, in conjunction with the evidence from many previous trials that potassium chloride has a significant blood pressure-lowering effect, suggest that potassium citrate has a similar effect on blood pressure as potassium chloride. These results support other evidence for an increase in potassium intake and indicate that potassium does not need to be given in the form of chloride to lower blood pressure. Increasing the consumption of foods high in potassium is likely to have the same effect on blood pressure as potassium chloride.