Effect of supplementation with Chlorella vulgaris on lipid profile in adults: A systematic review and dose-response meta-analysis of randomized controlled trials

Abstract

Objective: To summarize available findings on the effect of Chlorella vulgaris supplementation on lipid profile in adults. Design: Systematic review and meta-analysis of randomized controlled trials (RCTs). Setting: This study followed 2020 PRISMA guideline. We performed a systematic search in the online databases to identify relevant articles and then, extracted required data from each paper for the meta-analysis. Random-effects models were used to obtain overall mean difference (MD) comparing Chlorella vulgaris supplementation with a control group. Main outcome measures: Blood lipids including triglyceride (TG), total cholesterol (TC), LDL-C, and HDL-C. Results: In total, 10 RCTs with a total sample size of 539 adults (264 in the Chlorella vulgaris group and 275 in the control group) were included. Of the 10 RCTs, four had a low risk of bias for all aspects of the Cochrane risk of bias tool. Also, only two studies determined the chlorella content, purity, potency, and contamination of the supplements used in the intervention. Combining results from these studies showed a summary MD of 2.11 mg/ dL (95 CI: 7.28 to 3.06) for TG, 7.47 mg/dL (95 CI: 12.98 to 1.96) for TC, 7.71 mg/dL (95 CI: 14.05 to 1.37) for LDL-C, and 0.45 mg/dL (95 CI: 0.67 to 1.57) for HDL-C, indicating a beneficial effect of Chlorella vulgaris supplementation on TC and LDL-C levels. Based on the dose-response analysis, the reducing effect of Chlorella vulgaris supplementation on LDL-C levels was seen at the dosages between zero and 1500 mg/ d (P for non-linearity= 0.01), whereas in higher amounts, this effect was not significant. Conclusion: We found that Chlorella vulgaris supplementation had a beneficial effect on TC and LDL-C levels with no significant effect on TG and HDL-C levels.