Magnesium Lowers BP in Patients With Hypertension, Hypomagnesemia

Individuals with hypertension and hypomagnesemia may have their blood pressure (BP) significantly lowered with magnesium supplementation, according to study findings published in Hypertension.

Investigators analyzed the association between magnesium supplementation and BP among adults with normotensive and hypertensive BP ranges, with and without clinical conditions.

The investigators conducted a systematic review and meta-analysis searching multiple medical databases from inception until mid-May 2024 for articles in English of observational studies and randomized controlled trials. The included studies examined the effect of magnesium supplementation on systolic BP (SBP) and diastolic BP (DBP) among patients aged at least 18 years (range, 18-77 years) with at least a 4-week intervention period, and included a placebo or control group.  Studies with individuals who were pregnant, or with altered diet or medication during the intervention period, were among those excluded, as were studies with a cross-sectional design.

Overall, 38 randomized controlled trials were included in the analysis. The overall analysis population was 2709 patients, with 1448 receiving magnesium supplementation and 1392 receiving placebo, and 131 patients were involved in crossover studies and received both magnesium and placebo. Magnesium dose varied by study (range, 82.3-637.0 mg), with a median dose of 365.0 mg. Random effects meta-analysis was used to calculate mean differences in BP changes. Intervention periods ranged from 4 to 24 weeks, with a median of 12 weeks.

Our findings support the beneficial effect of magnesium on reducing BP among populations with hypertension and hypomagnesemia…

Compared with placebo, magnesium supplementation resulted in a SBP reduction of

-2.81 mm Hg (95% CI, -4.32 to -1.29; I²=78%) and a DBP reduction of -2.05 mm Hg (95% CI, -3.23 to -0.88; I²=88%; all P <.001). BP was measured in a seated position in 22 studies and a supine position in 13 studies.

Greater SBP reductions were noted among individuals on BP-lowering medication

(-7.68 mm Hg) and those with hypomagnesemia (-5.97 mm Hg). Greater DBP reductions were noted in the same individuals, those on BP-lowering medication (-2.96 mm Hg) and those with hypomagnesemia (-4.75 mm Hg; all P <.05). Statistical significance was not reached in the normotensive groups.

Across studies, high heterogeneity was found, with 25 studies assessed as having some concerns for risk of bias and 4 studies rated as high-risk. Between magnesium and BP changes, no dose-response relationship was found (all P ≥.20).

Study limitations include lack of dietary intake data, the wide range of magnesium doses between studies, and use of serum magnesium categories to determine hypomagnesemia and normomagnesemia.

“Our findings support the beneficial effect of magnesium on reducing BP among populations with hypertension and hypomagnesemia, although effects should be interpreted with caution due to high heterogeneity of studies,” the investigators concluded.

Disclosure: One study author declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.