Combinations of potassium, calcium, and magnesium supplements in hypertension. Efficacy of potassium and magnesium in essential hypertension: a double-blind, placebo controlled, crossover study. Calcium treatment of essential hypertension in elderly patients evaluated by 24 H monitoring. Dietary calcium supplementation as a treatment for mild hypertension. Double-blind randomized, crossover trial of calcium supplementation in essential hypertension. Calcium supplementation reduces blood pressure during pregnancy: results of a randomized controlled clinical trial. Effects of magnesium supplementation in hypertensive patients: assessment by office, home, and ambulatory blood pressures. Placebo-controlled trial of potassium supplements in black patients with mild essential hypertension. Effect of oral calcium supplementation on blood pressure in patients with previously untreated hypertension: a randomised, double-blind, placebo-controlled, crossover study.
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. 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. We used 24-h monitoring of blood pressure (BP) to evaluate the effect of calcium supplementation on mild to moderate essential hypertension in elderly hospitalized patients for the first time in a controlled crossover study. The mean systolic and diastolic BP over a period of 24 h declined by 13.6 mm Hg (P less than .005) and 5.0 mm Hg (P less than .05) respectively in patients whose diet was supplemented with 1 g of elemental calcium in the form of oystershell electrolysate (AA calcium). Serum ionized calcium and urinary calcium and sodium excretion increased (serum Ca2+ 0.16 +/- 0.03 mEq/L, P less than .05; FECa 0.5 +/- 0.2%, P less than .05; FENa 0.4 +/- 0.1%, P less than .05) and plasma parathyroid hormone was suppressed (12.2 +/- 2.3 pg/mL, P less than .005). These data suggest that supplementation of dietary calcium may contribute to a reduction of BP in elderly patients with essential hypertension. The blood pressure responses of 19 mildly hypertensive (diastolic blood pressure 90-104 mmHg) individuals to treatment with either 1200 mg of elemental calcium supplementation or placebo were assessed weekly in a 6-month randomized, double-blind, placebo-controlled crossover study. Both groups showed a decrease in blood pressure (calcium treated: 6 +/- 12 mmHg systolic, 7 +/- 7 mmHg diastolic; and placebo controlled: 9 +/- 14 mmHg systolic, 9 +/- 8 mmHg diastolic). Differences between the two groups were not significant (P greater than 0.1). There were no adverse effects to either treatment. This study does not support the hypothesis that dietary calcium supplementation is more effective than placebo in reducing blood pressure in mildly hypertensive individuals. In a double-blind, randomized, placebo-controlled, crossover trial, 23 middle-aged patients with mild to moderate essential hypertension were given an oral calcium supplement (1 g/day) for 8 weeks. At the end of this period, eight patients continued with this treatment for an additional 2 weeks but were also given 0.5 micrograms/day of 1,25-(OH)2 vitamin D3. In the 21 patients who completed the study, arterial pressure during the calcium-supplemented phase was almost identical to that of the placebo phase. In eight patients, mean arterial pressure (MAP) had changed by greater than 5 mmHg at the end of the calcium-supplemented period, compared with the end of the placebo phase (six patients showed an increase in MAP and two a decrease). Changes in arterial pressure were unrelated to age, plasma ionized calcium, parathyroid hormone (PTH), plasma renin activity (PRA), plasma aldosterone, 24-h urinary calcium, sodium and potassium and were only weakly related to body weight. In the eight patients who continued with the treatment of calcium plus 1,25-(OH)2 vitamin D3 after the 8-week study period, arterial pressure changed very little and not significantly. These results do not support the suggestion that calcium supplements lower arterial pressure in middle-aged subjects with mild to moderate essential hypertension. Fifty-two healthy pregnant women were enrolled in a double-blind, randomized, controlled clinical trial. After the 26th week of gestation, the women were given either 1.5 g of elemental calcium per day or a placebo. Subjects in the calcium group, after adjustment for race and initial blood pressure (BP), had a term mean systolic and diastolic BP value of 4-5 mmHg lower than those in the placebo group (P less than .05). The incidence of pregnancy-induced hypertension was 11.1% in the placebo group and 4.0% in the calcium group, a nonsignificant difference. Combining these values with previous data, we found a dose-effect relationship between calcium intake and BP reduction during the third trimester of pregnancy. Further research should be directed at understanding the mechanism of this effect and trying to demonstrate a reduction in pregnancy-induced hypertension with calcium supplementation in a larger population. An increase in magnesium intake has been suggested to lower blood pressure (BP). However, the results of clinical studies are inconsistent. We studied the effects of magnesium supplementation on office, home, and ambulatory BPs in patients with essential hypertension. Sixty untreated or treated patients (34 men and 26 women, aged 33 to 74 years) with office BP >140/90 mm Hg were assigned to an 8-week magnesium supplementation period or an 8-week control period in a randomized crossover design. The subjects were given 20 mmol/d magnesium in the form of magnesium oxide during the intervention period. In the control period, office, home, and average 24-hour BPs (mean+/-SE) were 148.6+/-1.6/90.0+/-0.9, 136.4+/-1.3/86.8+/-0.9, and 133.7+/-1.3/81.0+/-0.8 mmHg, respectively. All of these BPs were significantly lower in the magnesium supplementation period than in the control period, although the differences were small (office, 3.7+/-1.3/1.7+/-0.7 mmHg; home, 2.0+/-0.8/1.4+/-0.6 mmHg; 24-hour, 2.5+/-1.0/1.4+/-0.6 mm Hg). Serum concentration and urinary excretion of magnesium increased significantly with magnesium supplementation. Changes in 24-hour systolic and diastolic BPs were correlated negatively with baseline BP or changes in serum magnesium concentration. These results indicate that magnesium supplementation lowers BP in hypertensive subjects and this effect is greater in subjects with higher BP. Our study supports the usefulness of increasing magnesium intake as a lifestyle modification in the management of hypertension, although its antihypertensive effect may be small. 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. It has been claimed that calcium lowers BP. The present randomised, double-blind, placebo-controlled crossover study is the first to investigate the effect on BP of a high oral dose of calcium given for a long period to patients with previously untreated hypertension. Elemental calcium (2 g) was administered for 12 weeks interchanging with a period of 12 weeks of placebo. Twenty patients completed the protocol. There was no significant difference in change of BP during the period of additional calcium intake when compared with placebo (P = 0.33). The risk of not detecting a real BP-lowering effect of calcium of at least 3 mmHg was < 5%. No evidence for the existence of a subgroup of 'responders' was found. It is concluded that a high daily dose of calcium supplementation given for 12 weeks does not decrease BP in previously untreated patients with mild to moderate hypertension.
We found no robust evidence that supplements of any combination of potassium, magnesium or calcium reduce mortality, morbidity or BP in adults. More trials are needed to investigate whether the combination of potassium & magnesium is effective.