The Effect of Cranberry Consumption on C‐Reactive Protein and Interleukin‐6: A Systematic Review and Meta‐Analysis of Randomized Controlled Trials

TL;DR

This study reviews whether cranberry consumption affects two inflammation markers, finding no overall effect but some subgroup differences.

Contribution

A systematic review and meta-analysis of RCTs on cranberry's impact on CRP and IL-6.

Findings

Cranberry consumption did not significantly affect C-reactive protein (CRP) levels overall.

Cranberry consumption did not significantly influence interleukin-6 (IL-6) levels overall.

Cranberry consumption was associated with increased CRP in obese individuals or female-only studies.

Abstract

Previous clinical trials examining the effects of cranberry on inflammatory markers have yielded inconsistent results. This study specifically aimed to assess the influence of cranberry consumption on C‐reactive protein (CRP) and Interleukin‐6 in randomized controlled trials (RCTs). A thorough systematic review was conducted by searching ISI Web of Science, Cochrane Library, PubMed, Scopus, and Google Scholar up to December 21, 2024, with no language restrictions applied, by two independent authors. The results were synthesized using the DerSimonian and Laird random‐effects model. From an initial pool of 1882 articles, 10 were selected for the systematic review and meta‐analysis. The findings indicated that cranberry did not significantly influence CRP (weighted mean differences (WMD): 0.01 mg/L; 95% CI: −0.38 to 0.40, p = 0.95; I
2: 80.8%) or Interleukin‐6 (WMD: −0.26 pg/mL; 95% CI: −1.78 to 1.27, p = 0.74; I
2: 86.1%). However, it was observed that cranberry consumption was associated with a significant rise in CRP levels in obese individuals or in studies focused solely on women. Furthermore, research showed that the active ingredient in cranberry, when administered in powder form, could lead to a considerable increase in interleukin‐6 levels. This review and meta‐analysis suggest that cranberry supplementation did not affect CRP or Interleukin‐6 levels. To further assess and validate these results, more long‐term and well‐designed RCTs are needed.

Cranberry and inflammatory markers.

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