Controlled trial of long term oral potassium supplements in patients with mild hypertension. Placebo-controlled trial of potassium supplements in black patients with mild essential hypertension. Blood-pressure response to moderate sodium restriction and to potassium supplementation in mild essential hypertension. The influence of oral potassium citrate/bicarbonate on blood pressure in essential hypertension during unrestricted salt intake. Sodium restriction and potassium supplementation in young people with mildly elevated blood pressure. Effect of low sodium diet or potassium supplementation on adolescent blood pressure. Double-blind, placebo-controlled trial of potassium chloride in the treatment of mild hypertension. Efficacy of potassium and magnesium in essential hypertension: a double-blind, placebo controlled, crossover study. Combinations of potassium, calcium, and magnesium supplements in hypertension.
A 15 week randomised double blind placebo controlled trial of oral potassium supplements (48 mmol daily) was conducted in 37 patients who had mildly increased blood pressure and a normal dietary intake of sodium. After a two month run in and a one week baseline period the patients were randomly assigned to receive either potassium supplements (n = 18) or placebo (n = 19). By the third week of treatment blood pressure in the actively treated group had decreased significantly compared with that in the placebo group, though the decrease reached its maximum after 15 weeks. Urinary potassium excretion increased significantly in the group who received potassium supplements, but no significant changes were found in plasma sodium and potassium concentrations or in urinary sodium excretion. In a subgroup of 13 patients who underwent a further nine weeks of treatment with oral potassium supplements at half of the previous dose (24 mmol daily) their blood pressure, at the end of this second study period, was still significantly lower compared with their baseline value but not with that of the placebo group. These results show that moderate oral potassium supplements are associated with a long term reduction in blood pressure in patients who have mild hypertension. Forty-eight black patients with mildly increased blood pressure (BP) that had not yet been subjected to treatment took part in a double-blind clinical trial of the efficacy and tolerability of oral potassium supplements (64 mmol daily) versus a matching placebo (made of starch with coating) in a 16-week study. Potassium supplements produced a significant decrease in mean supine and standing BP within 4 weeks after treatment inception. Urinary potassium excretion increased significantly in the 24 patients who received potassium supplements (p less than 0.001). No significant changes occurred in plasma sodium and potassium concentrations or in urinary excretion of sodium during the study. All patients completed the trial without experiencing any notable untoward effects. These results are consistent with the premise that oral potassium supplements may exert hypotensive effects of clinically significant degree in patients with mild hypertension. To determine whether moderate restriction of dietary sodium content or supplementation of potassium intake reduces blood-pressure in patients with mild essential hypertension, twelve patients were put on three different diets--a control diet (180 mmol sodium/day), a sodium restricted diet (80 mmol/day). Each diet was taken for at least 4 weeks and the sequence of the regimens was randomised. At the completion of each regimen intra-arterial pressure was recorded continuously, and vasoactive hormones were measured hourly, for 24 h, under standardised conditions, in hospital. Compared with the control diet, sodium restriction was associated with lower blood-pressure readings in seven patients, higher levels in five, and an overall reduction in mean pressures of only 4.0/3.0 mm Hg (not significant). Individual differences in blood-pressure between these two diets correlated closely with concomitant differences in plasma renin activity (r = 0.75). Potassium supplementation also resulted in variable changes in arterial pressure, and the mean difference in pressure recordings (0.1/0.8 mm Hg) was insignificant. The results show that moderate restriction of sodium intake or supplementation of dietary potassium has variable effects on arterial pressure in individuals with mild essential hypertension, and that overall the blood-pressure changes induced are very small. Responsiveness of the renin-angiotensin system may limit the fall in blood-pressure induced by sodium restriction. In several trials, a blood pressure lowering effect of potassium chloride could be demonstrated. However, it is not known if other potassium salts are also effective. In a randomized cross-over trial, 12 patients with essential hypertension were treated for 8 weeks with placebo and 120 mmol potassium per day. Potassium was given together with 50% citrate and 50% bicarbonate as anions. Urinary potassium excretion rose from 61.8 +/- 8.1 to 166.7 +/- 21.2 mmol/24 hours during potassium supplementation. However, blood pressure and heart rate remained unchanged when compared to placebo. Non-chloride potassium salts may not be effective in lowering blood pressure in essential hypertension. Since potassium rich foods like fruits and vegetables contain potassium mostly as non-chloride salts, it appears to be premature to recommend a high dietary potassium intake as a mean to treat elevated blood pressure. Forty young subjects, aged 18 to 28 years, with mildly elevated blood pressure participated in a double-blind randomized three-period crossover study of the effect of sodium restriction with and without potassium supplementation on blood pressure. Dietary sodium intake was restricted for 18 weeks in which the patients received in random sequence 'slow-sodium' (90 mmol/day), 'slow-potassium' (72 mmol/day), and placebo tablets, each for 6 weeks. Mean urinary sodium excretion was 129 mmol/24 h in the slow-sodium period, 57 mmol/24 h during placebo, and 69 mmol/24 h during slow-potassium. Mean supine systolic blood pressure in the sixth week of the slow-potassium period was 3.3 mmHg lower than that at the end of the slow-sodium period (P less than 0.05). There was no significant difference in systolic or diastolic blood pressure between the placebo and the slow-sodium periods. The fall in systolic blood pressure in the low sodium/high potassium period was accompanied by a fall in cardiac index of 0.4 l/min per m2 body surface area (BSA) (P = 0.03). Our observations suggest a small hypotensive effect of moderate sodium restriction combined with high potassium intake in young hypertensive subjects. Sodium restriction alone has little effect on blood pressure in this group. The combination of a low sodium/high potassium diet may lower blood pressure by affecting cardiac output. Reducing the dietary sodium:potassium ratio may therefore be useful in the management of early primary hypertension. The roots of essential hypertension extend back into the first two decades of life, suggesting that effective intervention during those years may lead to a reduction in the incidence of adult hypertension. Decreasing the dietary sodium/potassium ratio offers a potentially effective approach to blood pressure reduction. This study tested the feasibility of 3-year sodium reduction or potassium supplementation in adolescents and the effect of these interventions on the rate of rise of blood pressure during adolescence. After 19,452 5th to 8th grade students were screened, 210 from the upper 15 percentiles of blood pressure distribution (105 boys, 105 girls) were randomly assigned to one of three groups: low sodium diet (70 mmol sodium intake per day), potassium chloride supplementation (normal diet plus 1 mmol/kg potassium chloride per day), or placebo (normal diet plus placebo capsule). Capsules for the potassium chloride and placebo groups were administered in a double blind protocol. Blood pressure was measured every 3 months for 3 years. The effect of the intervention was determined by comparing the rate of rise (slope) of blood pressure among the groups using a random-coefficient growth curve model. The boys groups and the girls placebo group had similar positive blood pressure slopes that were significantly different from zero. The girls low sodium group had a slightly negative slope (significantly lower than the slope of the girls placebo group), and the girls potassium group had a slightly positive slope. Both of these slopes were not significantly different from zero and were significantly lower than the slopes of the respective boys groups.(ABSTRACT TRUNCATED AT 250 WORDS) Epidemiological and experimental data suggest blood pressure-lowering effects of dietary potassium. A randomized, double-blind clinical trial was used to assess blood pressure response to orally administered potassium, 120 mEq/day, and to placebo in 101 adults with mild hypertension. Blood pressure was measured with a random-zero sphygmomanometer every 2 weeks of this 8-week trial. Systolic blood pressure in the potassium-treated group decreased by 6.4 +/- 13.7 (SD) mm Hg (p less than or equal to 0.025) compared with 0.11 +/- 13.0 mm Hg in the placebo-treated group (p = 0.96). Diastolic blood pressure in the potassium-treated group decreased by 4.1 +/- 8.3 mm Hg (p less than or equal to 0.05) compared with a 1.6 +/- 6.5 mm Hg decrease in placebo-treated subjects (p = 0.09). Baseline blood pressure of potassium-treated subjects was unexpectedly higher than that of controls. After correcting for baseline variation, blood pressure still decreased 3.4/1.8 mm Hg more in potassium recipients than in placebo recipients (p = 0.14 and 0.24, respectively). Blood pressure decreased by 19/13 mm Hg in five blacks taking potassium versus a 1/0 mm Hg increase in seven blacks taking placebo. Compliance with the potassium regimen was 91.5% by pill count; only one subject discontinued treatment because of side effects. In conclusion, 120 mEq/day of microencapsulated potassium chloride was well tolerated in adults with mild hypertension. An antihypertensive effect of potassium cannot be ruled out despite the fact that there was no statistically significant difference between potassium-treated and placebo-treated subjects after adjustment for differences in baseline blood pressure.(ABSTRACT TRUNCATED AT 250 WORDS) To evaluate the antihypertensive activity of potassium given alone or in combination with magnesium in patients with mild hypertension.
                A double blind, randomised, placebo controlled, crossover trial of 32 weeks' duration.
                Cardiology outpatient department, Sassoon General Hospitals, Pune, India.
                37 Adults with mild hypertension (diastolic blood pressure less than 110 mm Hg).
                Patients received either placebo or potassium 60 mmol/day alone or in combination with magnesium 20 mmol/day in a crossover design. No other drug treatment was allowed.
                Blood pressure and heart rate assessed at weekly intervals and biochemical parameters at monthly intervals.
                Potassium alone or in combination with magnesium produced a significant reduction in systolic and diastolic blood pressures (p less than 0.001) and a significant reduction in serum cholesterol concentration (p less than 0.05); other biochemical variables did not change. Magnesium did not have an additional effect. Urinary potassium excretion increased significantly in the groups who received potassium alone or in combination with magnesium. The drug was well tolerated and compliance was satisfactory.
                Potassium 60 mmol/day lowers arterial blood pressure in patients with mild hypertension. Giving magnesium as well has no added advantage. Dietary intakes of potassium, calcium, and magnesium have each been reported to lower blood pressure, but the extent of blood pressure reduction in epidemiological studies and clinical trials has tended to be small and inconsistent. We hypothesized that combinations of these mineral supplements would lower blood pressure and that the reductions would be greater than that usually reported in studies of each cation alone. One hundred twenty-five patients 82 men and 43 women) with untreated mild or borderline hypertension were randomly assigned to daily treatment with one of the following four regimens: 60 mmol potassium and 25 mmol (1000 mg) calcium, 60 mmol potassium and 15 mmol (360 mg) magnesium, calcium and magnesium, or placebo. Standardized clinic blood pressure measurements were obtained on 3 days at baseline and after 3 and 6 months of treatment. At baseline, systolic and diastolic blood pressures (mean +/- SD) were 139 +/- 12 and 90 +/- 4 mm Hg, respectively, and dietary intakes of potassium, calcium, and magnesium were 77 +/- 32, 19 +/- 13, and 12 +/- 52 mmol/d, respectively. The mean differences (with 95% confidence intervals) of the changes in systolic and diastolic blood pressures between the treatment and placebo groups were not significant: -0.7 (-4.3 to +2.9) and -0.4 (-2.9 to +2.1) for potassium and calcium, -1.3 (-4.4 to +1.8) and 0.4 (-2.5 to +3.3) for potassium and magnesium, and +2.1 (-1.8 to +6.0) and +2.2 (-1.0 to +5.4) for calcium and magnesium. In conclusion, this trial provides little evidence of an important role of combinations of cation supplements in the treatment of mild or borderline hypertension.
Potassium supplementation has no statistically significant effect on blood pressure. Due to small number of participants in the two high quality trials, the short duration of follow-up, and the unexplained heterogeneity between trials, the evidence about the effect of potassium supplementation on blood pressure is not conclusive. Further high quality RCTs of longer duration are required to clarify whether potassium supplementation can reduce blood pressure and improve health outcomes.