Effects of Walnut Consumption on Inflammatory Cytokines and Adipokines in Adults: A Systematic Review and Dose-Response Meta-Analysis.
Ghazal Mashayekhi, Damoon Ashtary-Larky, Mehdi Karimi et al.
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In 30 seconds
This systematic review and dose-response meta-analysis assessed randomized trials of walnut intake and inflammatory cytokines and adipokines in adults. Across 24 RCTs involving 2068 participants, walnut consumption was associated with small reductions in CRP (WMD: -1.0 mg/dL; 95% CI: -1.9 to -0.1; p = 0.031) and IL-6 (WMD: -0.11 pg/mL; 95% CI: -0.20, -0.01; p = 0.028). These findings were not robust in sensitivity analyses. No significant effects were found for TNF-α, adiponectin, or leptin; clinical relevance remains uncertain.
Key findings
- Walnut intake was associated with lower CRP (WMD: -1.0 mg/dL; 95% CI: -1.9 to -0.1; p = 0.031).
- IL-6 was lower with walnut intake (WMD: -0.11 pg/mL; 95% CI: -0.20, -0.01; p = 0.028), but sensitivity analyses found this result was not robust.
- No significant effects were observed for TNF-α (WMD: 0.21 pg/mL, p = 0.306), adiponectin (WMD: -0.17 ng/mL, p = 0.678), or leptin (WMD: 1.39 ng/mL, p = 0.314).
- Subgroup analyses suggested stronger anti-inflammatory effects with interventions lasting more than 12 weeks and doses above 50 g/day.
Why it matters
Inflammatory markers and adipokines are relevant to metabolic and cardiovascular disorders, so evidence about dietary effects may inform understanding of potential risk-modifying pathways. The pooled reductions in CRP and IL-6 were small and sensitive to influential studies, while other measured markers did not change significantly. The findings therefore do not establish a clinically meaningful benefit.
What to keep in mind
The CRP and IL-6 findings were not robust to exclusion of several influential studies, and the authors state that clinical relevance remains uncertain.