Clinical question
Is calcium supplementation versus placebo or control safe and effective for reducing blood pressure in normotensive people and for the prevention of primary hypertension?
Bottom line
An increase in calcium intake slightly reduced both systolic and diastolic blood pressure in normotensive people. The effect was confirmed in multiple prespecified subgroups, including a possible dose–response effect, reinforcing the efficacy of the intervention. The effects were observed after only 3.5 months of intervention.
Although the effect was small, an adequate calcium intake should be an objective to be reached in the general population.
Studies with interventions of calcium 1500mg per day or higher showed a greater reduction in systolic and diastolic blood pressure than those with interventions of less than 1000mg per day.
Studies performed in younger people tended to show greater reductions in systolic and diastolic blood pressure than those in older people.
Caveat
It is difficult to assess the effect of differences in the forms of calcium interventions, such as diet, fortification or supplements, since 14 of the 18 studies included in the meta‐analysis used supplementation as the intervention.
A greater effect was shown in studies lasting less than 6 months. There is some suggestion that the effect might be lost over time in populations with adequate calcium intake, as some studies showed no effect after 30 months and 1 year.
The quality of the evidence was rated as moderate to high.
Context
Hypertension is a major public health problem that increases the risk of cardiovascular and kidney diseases. Several studies have shown an inverse association between calcium intake and blood pressure, and small reductions in blood pressure have been shown to produce rapid reductions in cardiovascular disease risk even in individuals with normal blood pressure.
Cochrane Systematic Review
Cormick G, et al. Calcium supplementation for prevention of primary hypertension. Cochrane Database Syst Rev 2022;1:CD010037. This review contains 20 trials with a total of 3512 participants.
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