Sumac (Rhus coriaria L.) Supplementation on High-Sensitivity C-Reactive Protein Concentrations in Adults: A...

Chronic low-grade inflammation is implicated in the development of various metabolic and cardiovascular disorders. Sumac (Rhus coriaria L.) is a medicinal plant with potential anti-inflammatory properties. However, the effects of sumac supplementation on inflammatory biomarkers, particularly high-sensitivity C-reactive protein (hs-CRP), remain controversial.

This systematic review and meta-analysis aimed to evaluate the effect of sumac supplementation on hs-CRP concentrations in adults.

A systematic search was performed in PubMed, Scopus, Web of Science, and the Cochrane Library databases up to February 2025 to identify RCTs examining the impact of sumac supplementation on hs-CRP concentrations. Screening, data extraction, and risk of bias assessment were conducted independently. A random-effects model was used to calculate the overall effect size as the SMD with 95% CIs.

Seven RCTs were eligible for inclusion in this review. The pooled analysis demonstrated a significant reduction in hs-CRP concentrations following sumac supplementation compared with that in the control groups (SMD: -0.33; 95% CI: -0.64, -0.02; P = 0.03). Moreover, a significant heterogeneity was detected among the pooled effect sizes (P = 0.02; I ² = 60.2%). Subgroup analyses revealed that sumac supplementation led to a significant reduction in hs-CRP concentrations in trials that included both genders or in studies conducted on patients with nonalcoholic fatty liver disease, individuals with overweight, or those aged ≥45 y.

Sumac supplementation may significantly reduce hs-CRP concentrations in adults. Further high-quality, large-scale trials in various populations in terms of areas or health conditions are required to confirm these findings and determine the optimal dosage and duration for sumac supplementation to reduce inflammation.This trial is registered at PROSPERO database as CRD420251016622.