“There is long-standing interest in the promising yet unproven role of [magnesium] in the regulation of [blood pressure] for the prevention of hypertension, although evidence from human studies has been both inconsistent and controversial,” the researchers wrote.
Magnesium is an increasingly popular supplement in the United States. At the moment, somewhere between 70 to 80% of Americans are not meeting their recommended intakes of magnesium, but some experts forecast the supplement to surpass calcium sales by 2020.
The trials included in the meta-analysis by the included normo-tensive or hypertensive participants aged between 18 and 84. Of the 2,028 participants included, 1,010 received magnesium supplementation at a median dose of 368 mg/d for a median duration of three months and the other 1,018 received placebo.
The data indicated that magnesium supplementation “led to overall reductions in systolic [blood pressure] and diastolic [blood pressure]”.
“Our dose- and time-response analyses of data from 27 trials showed that oral [magnesium] supplementations at a dose of 200 mg/d or with a duration of 1 month was sufficient to significantly raise serum [magnesium],” added the researchers.
Most of the trials included were small with relatively high dropout rates, said the researchers, and they noted that they used serum magnesium to reflect magnesium status “although it may not be an optimally sensitive biomarker of magnesium status in the human body, because 0.3% of total body magnesium is present in serum,” they wrote.
Nevertheless, the meta-analysis adds to the building evidence that magnesium, often dubbed the “forgotten mineral,” may be beneficial to cardiovascular health.
Published online before print July 11, 2016, doi: 10.1161/HYPERTENSIONAHA.116.07664
"Effects of Magnesium Supplementation on Blood Pressure: A Meta-Analysis of Randomized Double-Blind Placebo-Controlled Trials"
Authors: X. Zhang, Y. Li, L.C. Del Gobbo, A. Rosanoff, J. Wang, W. Zhang, Y. Song