The daily dosage of magnesium supplements used ranged from 240 milligrams (mg) to 960 mg. Most trials had participants meet or exceed the U.S. Recommended Dietary Allowance for daily magnesium intake.
Sifting through the collected data, Song's team detected a small but significant link between magnesium intake and healthy reductions in blood pressure.
For example, the study found that taking about 368 mg of magnesium daily for about three months resulted in overall reductions in systolic blood pressure (the top number in a reading) of 2 millimeters of mercury (mm/Hg) and diastolic blood pressure (the bottom number) of 1.78 mm/Hg.
Higher magnesium levels were associated with better blood flow -- another factor linked to lower blood pressure, the researchers added.
Song and his colleagues believe that the benefits of magnesium in regulating blood pressure may only apply to people with a magnesium deficiency or insufficiency.
Still, the finding "underscores the importance of consuming a healthy diet that provides the recommended amount of magnesium as a strategy for helping to control blood pressure," American Heart Association spokeswoman Penny Kris-Etherton said in an AHA news release.