Scientific Study

Background and aims: Pistachio nuts have been considered to improve dysglycemia. However, there are controversial results. This systematic review and meta-analysis carried out to evaluate the effects of pistachio nuts on glycemic control and insulin sensitivity in patients with type 2 diabetes mellitus (T2DM), prediabetes, and metabolic syndrome. Methods: Medline/PubMed, ProQuest, Web of Knowledge, Scopus, Cochrane library, and ScienceDirect were systematically searched to find randomized controlled trials (RCTs). Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) checklist was used to conduct the study. Results: Six RCTs were included in the review. Treatment with pistachio nuts exerted a significant reduction in fasting blood glucose (FBG) level (OR = 1.7, 95% CI; 1.2-2.4, P = 0.002, I2 = 0.0%, P = 0.731) and homeostasis model assessment of insulin resistance (HOMA-IR) index (OR = 1.5, 95% CI; 1.0-2.4, P = 0.043, I2 = 0.0%, P = 0.617), but no significant improvement was observed in regard to hemoglobin A1c (HbA1c) level (OR = 1.4, 95% CI; 0.9-2.1 P = 0.089, I2 = 0.0%, P = 0.957) and fasting plasma insulin (FPI) level (OR = 1.3, 95% CI; 0.9-1.9, P = 0.133, I2 = 0.0%, P = 0.776). Conclusions: Pistachio nuts might cause a significant reduction in FBG and HOMA-IR, although HbA1c and FPI might not significantly improve in patients suffering from or at risk of T2DM.