Effects of synbiotic consumption on lipid profile: a systematic review and meta-analysis of randomized controlled clinical trials

Background and aims Existing evidence on the possible effects of synbiotics on lipid profile is inconclusive. The aim of the present systematic review was to clarify the effects of synbiotics consumption on lipid profile. Methods A systematic literature search of online databases PubMed, Scopus, ISI Web of science, Cochrane's library and Google Scholar was conducted up to January 2019. Randomized controlled trials (RCTs) investigating the effects of synbiotics on lipid profile in adults were included. The overall effect was presented as weighted mean difference (WMD) and 95% confidence interval (CI) in a random-effects meta-analysis model. Results A total of 23 RCTs with 1338 participants were included. Synbiotic consumption resulted in a significant decrease in plasma concentrations of total cholesterol (WMD = - 10.17 mg/dL; 95% CI - 15.74 to - 4.60; p < 0.001), triglyceride (WMD = - 14.30 mg/dL; 95% CI - 25.32 to - 3.28; p = 0.01), low-density lipoprotein cholesterol (WMD = - 8.32 mg/dL; 95% CI - 13.21 to - 3.43; p < 0.001), and an increase in plasma high-density lipoprotein cholesterol (WMD = 1.3 mg/dL; 95% CI 0.03 to 2.56; p = 0.04) levels compared to control (placebo supplements/control foods/conventional products). The effects are more pronounced when synbiotics supplements are consumed for > 8 weeks. Conclusion Synbiotic supplements may be beneficial to improve lipid profile, especially when they are consumed for > 8 weeks.