J Hum Nutr Diet. 2026 Dec;39(6):e70354. doi: 10.1111/jhn.70354.
ABSTRACT
BACKGROUND: Inflammation and dysregulation of adipokines play key roles in the development of metabolic and cardiovascular disorders. Walnuts (Juglans regia L.), rich in polyunsaturated fatty acids, fiber, and antioxidants, may modulate inflammatory and metabolic pathways; however, evidence from interventional studies remains inconsistent. This systematic review and dose-response meta-analysis aimed to determine the effects of walnut consumption on inflammatory cytokines and adipokines in adults.
METHODS: A comprehensive literature search was conducted in databases through July 2026 to identify relevant randomized controlled trials (RCTs) examining the effects of walnut intake on C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), adiponectin, and leptin. Weighted mean differences (WMDs) and 95% confidence intervals (CIs) were pooled. Subgroup, sensitivity, and non-linear dose-response analyses were performed.
RESULTS: The pooled analysis of 24 RCTs (2068 participants) showed that Walnut intake was associated with a small reduction in CRP concentrations (WMD: -1.0 mg/dL; 95% CI: -1.9 to -0.1; p = 0.031) and IL-6 concentrations (WMD: -0.11 pg/mL; 95% CI: -0.20, -0.01; p = 0.028). However, sensitivity analyses indicated that this finding was not robust to the exclusion of several influential studies. 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 revealed more potent anti-inflammatory effects with interventions lasting more than 12 weeks and doses above 50 g/day.
CONCLUSIONS: Walnut consumption may be associated with small reductions in CRP and IL-6 levels, without significant effects on TNF-α or adipokine concentrations. However, these effects are modest, and their clinical relevance remains uncertain.
PMID:42947498 | DOI:10.1111/jhn.70354