Effect of magnesium supplements on serum C-reactive protein: a systematic review and meta-analysis
What this study found
Magnesium supplementation significantly reduced serum C-reactive protein (CRP) by -1.33 mg/L (95% CI -2.63 to -0.02). IL-6 and fasting blood glucose showed no significant changes. Results were robust to sensitivity analyses; CRP change did not depend on dose or duration. Subgroup with baseline CRP ≥ 2 mg/dL showed greater reductions (-2.95 mg/dL, p<0.001). Publication bias was not confirmed. Authors conclude that magnesium may lower CRP levels, but larger, longer trials are needed to confirm and clarify mechanisms.
- Study & population
- Eight randomized controlled trials; 349 participants; adults aged 18–85; mixed genders (one study female-only); parallel or crossover designs.
- Intervention
- Oral magnesium supplementation; daily dose 320–1500 mg; duration from 8 h to 6.5 months.
- Key limitation
- Small sample sizes in most trials; heterogeneity across populations and baseline CRP; varying magnesium doses and durations; some studies had risk of bias in allocation or blinding; potential publication bias; limited number of studies and short follow-up.
View source
Open PDFOriginal abstract
Introduction The aim of the study was to undertake a systematic review and meta-analysis of prospective studies to determine the effect of magnesium (Mg) supplementation on C-reactive protein (CRP). Design: Systematic review and meta-analysis of randomised controlled trials (RCTs). Material and methods Data sources: PubMed-Medline, Web of Science, Cochrane Database, and Google Scholar databases were searched (up until December 2016). Eligibility criteria: Randomized controlled trials evaluating the impact of Mg supplementation on CRP. We used random effects models meta-analysis for quantitative data synthesis. For sensitivity analysis was used the leave-one-out method. Heterogeneity was quantitatively assessed using the I 2 index. Main outcome: Level of CRP after Mg supplementation. Results From a total of 96 entries identified via searches, eight studies were included in the final selection. The meta-analysis indicated a significant reduction in serum CRP concentrations following Mg supplementation (weighted mean difference (WMD) –1.33 mg/l; 95% CI: –2.63 to –0.02, heterogeneity p < 0.123; I 2 = 29.1%). The WMD for interleukin 6 was –0.16 pg/dl (95% CI: –3.52 to 3.26, heterogeneity p = 0.802; I 2 = 2.3%), and 0.61 mg/dl (95% CI: –2.72 to 1.48, p = 0.182, heterogeneity p = 0.742; I 2 = 6.1%) for fasting blood glucose. These findings were robust in sensitivity analyses. Random-effects meta-regression revealed that changes in serum CRP levels were independent of the dosage of Mg supplementation (slope: –0.004; 95% CI: –0.03, 0.02; p = 0.720) or duration of follow-up (slope: –0.06; 95% CI: –0.37, 0.24; p = 0.681). Conclusions This meta-analysis suggests that Mg supplementation significantly reduces serum CRP level. RCTs with a larger sample size and a longer follow-up period should be considered for future investigations to give an unequivocal answer.