Objective: Several randomized controlled trials (RCTs) have assessed the effects of nut consumption on inflammatory markers. However, the results have been inconsistent. The aim of this meta-analysis of RCTs was to quantitatively evaluate the effects of nut consumption on selected inflammatory markers. Methods: PubMed, Embase, Cochrane Library database, and Google Scholar were searched for published RCTs that reported the effects of nuts on inflammatory markers as primary or secondary outcomes in an adult population (aged ≥18 y). Summary estimates of weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated using random-effects meta-analysis. Results: Twenty-three RCTs met the inclusion criteria. Overall, nut consumption significantly reduced the levels of intercellular adhesion molecule (ICAM)-1 (WMD, −0.17; 95% CI, −0.32 to −0.03; P = 0.01), but had no significant effect on other inflammatory markers. In the subgroup analyses by nut types, mixed nuts had a significant effect on ICAM-1 reduction. The significant effect of nuts on ICAM-1 reduction was only observed in parallel, but not crossover RCTs. Additionally, nut consumption significantly reduced ICAM-1 and vascular cell adhesion molecule-1 levels in long-term (≥12 wk), but not short-term (<12 wk) RCTs. No significant heterogeneity or publication bias was observed in the studies included. Conclusions: Nut consumption significantly reduced ICAM-1 levels, but had no effect on other inflammatory markers. More studies are needed to assess the effects of nuts on inflammation.
- Inflammatory markers
- Intercellular adhesion molecule
- Nut consumption
- Randomized controlled trials