Magnesium Supplementation and Blood Pressure: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Area of Science:

• Nutritional Science
• Cardiovascular Health
• Clinical Trials

Background:

• Conflicting research exists on magnesium's impact on blood pressure (BP) in both hypertensive and normotensive individuals.
• Understanding the precise relationship between magnesium intake and BP is crucial for public health and clinical practice.

Purpose of the Study:

• To conduct a meta-analysis and dose-response analysis to clarify the association between magnesium supplementation and BP.
• To evaluate the effects of magnesium in randomized controlled trials (RCTs) with a minimum duration of four weeks.

Main Methods:

• A systematic meta-analysis of 38 RCTs involving 2709 participants was performed.
• Elemental magnesium doses ranged from 82.3 mg to 637 mg (median 365 mg) over a median intervention period of 12 weeks.
• Random effects meta-analysis was used to calculate mean differences in BP changes; cubic spline regression modeled dose-response.

Main Results:

• Magnesium supplementation significantly reduced systolic BP by -2.81 mmHg and diastolic BP by -2.05 mmHg compared to placebo.
• Greater BP reductions were observed in hypertensive individuals on BP-lowering medication (-7.68 mmHg systolic, -2.96 mmHg diastolic) and those with hypomagnesemia (-5.97 mmHg systolic, -4.75 mmHg diastolic).
• No statistically significant BP reduction was found in normotensive groups, and no dose-response relationship between magnesium intake and BP changes was identified (P≥0.20).

Conclusions:

• Magnesium intake demonstrates a beneficial effect in lowering BP for hypertensive individuals and those with hypomagnesemia.
• Findings should be interpreted cautiously due to significant heterogeneity across studies.
• Further large-scale, well-designed trials are necessary to confirm dose-response relationships and optimize supplementation strategies for specific populations.