The effect of probiotic fermented milk products on blood lipid concentrations: A systematic review and meta-analysis of randomized controlled trials

Aim: Fermented milk products are suggested as a supplementary therapy to help reduce blood lipid levels. However, the results of clinical studies are conflicting. Data synthesis: This study systematically reviewed 39 randomized controlled trials (n Z 2237 participants) to investigate the effect of probiotic fermented milk products on blood lipids. A meta-analysis was performed using random effects models, with weighted mean differences (WMDs) and 95% confidence interval (CI). Statistically significant reductions in blood lowdensity lipoprotein cholesterol (LDL-C) (WMD: -7.34 mg/dL, 95% CI: from -10.04 to -4.65, and P < 0.001) and total cholesterol (TC) concentrations (WMD: -8.30 mg/dL, 95% CI: from -11.42 to -5.18, and P 0.001) were observed. No statistically significant effect of probiotic fermented milk was observed on blood high-density lipoprotein cholesterol (HDL-C) and triacylglycerol (TAG) levels. The effect on TC and LDL-C level was more pronounced in men, and a greater reduction in TAG was observed in trials with longer interventions ( 8 weeks) as compared to their counterparts. Conclusions: Available evidence suggests that probiotic fermented milk products may help to reduce serum TC and LDL-C cholesterol levels, particularly in men and when they are consumed Aim: Fermented milk products are suggested as a supplementary therapy to help reduce blood lipid levels. However, the results of clinical studies are conflicting. Data synthesis: This study systematically reviewed 39 randomized controlled trials (n Z 2237 participants) to investigate the effect of probiotic fermented milk products on blood lipids. A meta-analysis was performed using random effects models, with weighted mean differences (WMDs) and 95% confidence interval (CI). Statistically significant reductions in blood low density lipoprotein cholesterol (LDL-C) (WMD:-7.34 mg/dL, 95% CI: from-10.04 to-4.65, and P < 0.001) and total cholesterol (TC) concentrations (WMD:-8.30 mg/dL, 95% CI: from-11.42 to-5.18, and P 0.001) were observed. No statistically significant effect of probiotic fermented milk was observed on blood high-density lipoprotein cholesterol (HDL-C) and triacylglycerol (TAG) levels. The effect on TC and LDL-C level was more pronounced in men, and a greater reduction in TAG was observed in trials with longer interventions ( 8 weeks) as compared to their counterparts. Conclusions: Available evidence suggests that probiotic fermented milk products may help to reduce serum TC and LDL-C cholesterol levels, particularly in men and when they are consumed for >8 weeks. ? 2021 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.