A Meta-analysis of Randomized Control Trials: The Impact of Vitamin C Supplementation on Serum CRP and Serum hs-CRP Concentrations.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 30332942 · doi:10.2174/1381612824666181017101810
What was done
The authors searched Scopus, PubMed, and Google Scholar up to May 2018 for randomized controlled trials evaluating the effect of vitamin C supplementation on serum C-reactive protein (CRP) and high-sensitivity CRP (hs-CRP). Net changes from baseline to study completion were pooled using a random-effects model to calculate weighted mean differences (WMDs) and 95% confidence intervals (CIs).
What was found
Twelve studies comprising 446 participants in vitamin C groups and 447 in control groups were analyzed. Vitamin C significantly reduced circulating CRP levels (WMD -0.23 mg/L, 95% CI -0.44 to -0.03, p=0.02) with significant heterogeneity across trials. Subgroup analyses showed significant reductions in hs-CRP (-0.43 mg/L, 95% CI -0.76 to -0.10), subjects with baseline CRP 3 mg/L or higher (-1.48 mg/L, 95% CI -2.84 to -0.11), subjects younger than 60 years (-0.23 mg/L, 95% CI -0.44 to -0.01), and intravenous administration (-0.89 mg/L, 95% CI -1.49 to -0.30).
Why it matters
Vitamin C supplementation appears to modestly reduce systemic inflammatory markers, with the largest reductions seen in individuals with elevated baseline inflammation or when administered intravenously.
Limits
Significant heterogeneity was present across the included trials. The total sample size across 12 studies was modest (893 total participants). The abstract does not report specific clinical conditions of the participants, intervention durations, oral dosage amounts, or risk of bias assessments.
Cited by
- context Supplementing with 2 grams of vitamin C per day lowers C-reactive protein levels.