Dietary magnesium intake is inversely associated with serum C-reactive protein levels: meta-analysis and systematic review

BACKGROUND/OBJECTIVES: The aim of this study was to quantitatively summarize the association of dietary magnesium (Mg) intake with serum C-reactive protein (CRP) levels in the general population. SUBJECTS/METHODS: Observational and experimental studies through February 2013 were reviewed in PubMed and EMBASE. Additional information was retrieved through Google or hand search of related reference lists. The main outcome is either adjusted geometric mean of CRP or odds ratio (OR) of having serum CRP >= 3 mg/l. Meta-regression was used to determine the linear association of dietary Mg intake and adjusted geometric means of CRP levels. A fixed-effects model was used to pool ORs of interest, comparing those in the lowest with those in the highest group of dietary Mg intake. RESULTS: A data set derived from seven cross-sectional studies including 32 918 participants was quantitatively assessed. A weighted inverse association between Mg intake and serum CRP levels was observed (beta-coefficient: -0.0028; 95% confidence interval (CI), -0.0043 to -0.0013; P-trend = 0.001) from four cross-sectional studies. The pooled OR (95% CI) of having CRP >= 3 mg/l was 1.49 (1.18-1.89) on comparing the lowest to the highest group of Mg intake from three studies with the data available. Qualitative assessment among five intervention studies also showed a potential beneficial effect of Mg intake on serum CRP levels. CONCLUSIONS: This meta-analysis and systematic review indicates that dietary Mg intake is significantly and inversely associated with serum CRP levels. The potential beneficial effect of Mg intake on chronic diseases may be, at least in part, explained by inhibiting inflammation.