The effect of pomegranate juice supplementation on C-reactive protein levels: GRADE-assessed systematic review and dose-response updated meta-analysis of data from randomized controlled trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 38553998 · doi:10.1002/ptr.8188
What was done
A systematic review and meta-analysis of randomized controlled trials (RCTs) searched PubMed, Scopus, and Web of Science through July 2023 to evaluate the effect of pomegranate juice (PJ) supplementation on C-reactive protein (CRP) levels. Risk of bias was assessed, and pooled effect sizes were calculated using random-effects models as weighted mean differences (WMD) with 95% confidence intervals (CI). Linear and nonlinear dose-response meta-regressions were also conducted across 11 included studies (13 effect sizes, 696 participants).
What was found
PJ supplementation significantly reduced CRP levels compared to control groups (WMD: -2.55 mg/L; 95% CI: -3.44 to -1.66; p < 0.001). Significant reductions were observed in subgroups of both sexes or females only, Iranian populations, individuals aged 40 years and older, participants with type 2 diabetes or polycystic ovary syndrome, and trials using dosages < 250 mL/day. Dose-response and meta-regression analyses found no significant linear or nonlinear relationship between PJ dose or duration and CRP changes.
Why it matters
This updated meta-analysis suggests that pomegranate juice can reduce circulating CRP, providing quantitative evidence of an anti-inflammatory effect where earlier meta-analyses had reported nonsignificant findings.
Limits
The total sample size across all 11 studies was modest (696 participants). The absence of a significant dose-response relationship obscures optimal dosing and intervention duration. Significant subgroup results were clustered in specific demographics (e.g., Iranian cohorts, specific metabolic conditions), limiting generalizability to broader healthy or diverse populations.
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