A systematic review and meta-analysis: The effects of probiotic supplementation on metabolic profile in patients with neurological disorders

•Probiotic supplementation on metabolic status in patients with neurological disorders was evaluated.•Probiotic supplementation improved CRP, MDA, insulin and HOMA-IR.•Probiotic supplementation decreased triglycerides and VLDL-cholesterol, and HDL-cholesterol levels increased.•Further trials are needed to recruit more participants in management of patients with neurological disorders. The objective of meta-analysis of randomized controlled trials (RCTs) was to evaluate the effects of probiotic supplementation on metabolic status in patients with neurological disorders. The following databases were search up to April 2019: Pubmed, Scopus, Google scholar, Web of Science, and Cochrane Central Register of Controlled Trials. The quality of the relevant extracted data was assessed according to the Cochrane risk of bias tool. Data were pooled by the use of the inverse variance method and expressed as mean difference with 95 % Confidence Intervals (95 % CI). Nine studies were included in this meta-analysis. The findings suggested that probiotic supplementation resulted in a significant reduction in C-reactive protein (CRP) [Weighted Mean Difference (WMD): -1.06; 95 % CI: -1.80, -0.32] and malondialdehyde (MDA) levels (WMD: -0.32; 95 % CI: -0.46, -0.18). Supplementation with probiotics also significantly reduced insulin (WMD: -3.02; 95 % CI: -3.88, -2.15) and homeostatic model assessment for insulin resistance (HOMA-IR) (WMD: -0.71; 95 % CI: -0.89, -0.52). Probiotics significantly reduced triglycerides (WMD: -18.38; 95 % CI: -25.50, -11.26) and VLDL-cholesterol (WMD: -3.16; 95 % CI: -4.53, -1.79), while they increased HDL-cholesterol levels (WMD: 1.52; 95 % CI: 0.29, 2.75). This meta-analysis demonstrated that taking probiotic by patients with neurological disorders had beneficial effects on CRP, MDA, insulin, HOMA-IR, triglycerides, VLDL-cholesterol and HDL-cholesterol levels, but did not affect other metabolic parameters.