Effect of pistachio on plasma lipids concentration: a meta-analysis of randomized controlled trials

Dyslipidemia and lipoprotein metabolism disorder are involved in pathogenesis of many important diseases such as diabetes, atherosclerosis, acute pancreatitis, and malignancies. The present study aimed to evaluate the effect of pistachio on plasma lipids. Electronic databases including Scopus, Pubmed, Science Direct, and Cochrane library were searched with the keywords “lipoprotein”, “blood lipid”, “dyslipidemia” or “hyperlipidemia” with “Pistachio” until June 2019. Two review authors independently checked eligibility and extracted data using a standard form. Information extracted included characteristics of the patients, dose of treatment, trial duration, quality score, and trial outcomes. Four randomized clinical trials with 213 subjects worked on the effect of pistachio on blood lipids were included. Comparison of pistachio rich diet with control yielded a significant effect size of -2.6 (95% CI:-4.4 –-0.7, p=0.006) for mean reduction in total cholesterol, a significant effect size of 5.1 (95% CI: 1.8 –8.3, p=0.002) for mean increase in HDL-cholesterol, a non-significant effect sizeof -0.3 (95% CI: -0.8 –0.3, p=0.4) for mean reduction in LDL-cholesterol and a non-significant effect size of -1.3 (95% CI: -4.4 –1.7, p=0.4) for mean reduction in triglyceride from baseline. The results demonstrated significant effect of pistachio on reducing total cholesterol and increasing HDL-cholesterol; however, its effect on lowering LDL-cholesterol and triglyceride was not significant. Further clinical trials are needed to confirm whether pistachio consumption for a certain period of time can significantly influence blood lipids.