Impact of different types of tree nut, peanut, and soy nut consumption on serum C-reactive protein (CRP) A systematic review and meta-analysis of randomized controlled clinical trials

Background: The effects of different types of tree nut, peanut, and soy nut consumption on serum C - reactive protein (CRP) are not well established. we aimed to undertake a systematic review and meta-analysis of prospective studies to determine the effect of nut consumption (tree nuts, peanuts, and soy nuts) on serum CRP. Method: PubMed-Medline, Web of Science, Cochrane Database, and Google Scholar databases were searched (up until April 20 2016) to identify prospective studies evaluating the impact of tree nut, peanut, and soy nut consumption on serum CRP. Random effects models meta-analysis was used for quantitative data synthesis. Sensitivity analysis was conducted using the leave-one-out method. Heterogeneity was quantitatively assessed using the I-2 index. Systematic review registration: CRD42016038044. Results: From a total of 844 entries identified via searches, 20 studies were included in the final selection. The meta-analysis indicated a nonsignificant increase in serum CRP concentrations following nut consumption (weighted mean difference [WMD] 0.17 mg/L, (95% CI -0.67 to 0.33, I-2 52.1%). The WMDs for IL6 was -0.06(ng/dL), (95% CI -0.69 to 0.56, I-2 9.6%), -0.71(mg/dL), (95% CI -1.11 to -0.30, I-2 6.3%), for leptin, and -0.60(mg/dL), (95% CI -1.88 to 0.68, I-2 5.6%) for adiponectin, and -0.18(mg/dL), (95% CI -1.24 to 0.88, I-2 9.3%) for IL10 and -0.37 (pg/mL), (95% CI -0.90 to 0.16, I-2 7.9%) for TNF-alpha. These findings were robust in sensitivity analyses. Conclusions: This meta-analysis suggests that nut consumption significantly decrease leptin while have no significant effect on CRP, IL6, adiponectin, IL10, and TNF-alpha.