Effects of pistachios on glycemic control: A systematic review and meta-analysis of randomized controlled trials.

To evaluate the effects of pistachio consumption on the glucoregulatory status in individuals with a high risk of cardiovascular disease (CVD), a systematic review and meta-analysis of randomized controlled trials (RCT) was conducted. Online databases including PubMed, Scopus, Web of Science, and Cochrane Library were searched from inception until June 2019. Human trials that reported data for fasting blood sugar (FBS), fasting insulin, and homeostasis model assessment of insulin resistance (HOMA-IR) were included. Data were pooled using the random effect models and expressed as weighted mean difference (WMD) with 95% confidence interval (CI). Eight RCT were included in the analyses. Pistachio consumption, exchanged isocalorically for other foods, decreased FBS (WMD: -5.32 mg/dL, 95% CI: -7.80 to -2.64, P < 0.001), and insulin (WMD: -1.86 µIU/mL, 95% CI: -3.13 to -0.59, P < 0.01) concentrations in individuals with a high risk of cardiovascular disease. However, no changes were observed in the levels of HOMA-IR between the groups (WMD: -0.66, 95% CI: -1.89 to 0.58, P = 0.30). Pistachio consumption may improve glucoregulatory status in individuals at risk for CVD, as evidenced by reduced FBS and insulin concentrations. However, due to the limited availability of studies with diabetic cases and relatively small sample sizes of available studies, well-designed trials with adequate sample sizes aimed at diabetic populations are recommended.