Effect of synbiotics on the cardiovascular risk factors in patients with non-alcoholic fatty liver: a GRADE assessed systematic review and meta-analysis.

Minfang Lv, Ghavam Shafagh, Saiting Yu

Journal: BMC gastroenterology 2025;25(1):407

PMID: 40419987

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Plain Language Summary

Gut microbiota may play a role in the development of non-alcoholic fatty liver disease (NAFLD) and heart disease by acting on inflammation and digestion. This systematic review and meta-analysis of 15 randomised controlled trials examined the effects of synbiotics (a combination of probiotics and prebiotics) on the risk of heart disease in patients with NAFLD.

The results showed that synbiotics had no effect on blood pressure, blood lipid levels or most anthropometric measures. There was a decrease in weight following synbiotics. Some but not all markers of inflammation were decreased with supplementation.

It was concluded that synbiotics could have a positive impact on certain heart disease risk factors among individuals with NAFLD. However, the results from the included studies varied, highlighting the need for careful interpretation of the data. This study could be used by healthcare professionals to understand that synbiotic supplementation has limited effect on blood pressure, anthropometrics, and blood lipid levels. However, they could be of benefit to weight loss in individuals with NAFLD.

Abstract

INTRODUCTION

Several studies revealed that synbiotics have been beneficial in managing non-alcoholic fatty liver disease (NAFLD), but the findings are conflicting. We aimed to assess the effect of synbiotic supplementation on cardiovascular risk factors in patients with NAFLD.

METHODS

A thorough literature search was conducted to identify relevant studies up to July 2024, including publications from Pubmed, Embase, Cochrane, Scopus, and the Web of Science. Standardized mean difference (SMD) was used, and data with a 95% confidence interval (CI) were presented.

RESULTS

Sixteen RCTs were included, involving NAFLD patients and synbiotic supplementation. No significant effects were found on blood pressure (SBP: SMD - 6.68, p = 0.234; DBP: SMD - 4.31, p = 0.391), anthropometric measures (weight: SMD - 0.78, p = 0.126; BMI: SMD - 0.21, p = 0.182; waist circumference: SMD - 0.53, p = 0.095), or lipid profile (triglycerides: SMD - 3.67, p = 0.266; total cholesterol: SMD - 0.61, p = 0.059; low-density lipoprotein: SMD - 3.09, p = 0.215; high-density lipoprotein: SMD 0.49, p = 0.219). Synbiotics significantly reduced CRP levels (SMD - 1.83, p = 0.019) but had no significant effect on TNF-α (SMD - 1.95, p = 0.087). Synbiotic led to a significant reduction in weight following adjustment of publication bias (SMD - 1.16, p < 0.05).

CONCLUSION

Overall, synbiotic supplementation does not significantly impact blood pressure, anthropometric indices, or lipid profile parameters in patients with NAFLD, except for a significant reduction in weight after adjusting for publication bias. Synbiotic supplementation significantly reduces CRP levels but has no effect on TNF-α.

Address: Department of Nursing, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China. [email protected].; Faculty of Medicine, Lorestan Medical University, Khorramabad, Iran. [email protected].; Department of Nursing, The Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, Zhejiang, China.

DOI: 10.1186/s12876-025-03789-z