TABLE 1.
Characteristics of included trials, stratified by probiotics and synbiotics1
| First author (publication year) | Patient population | Total sample size | Intervention of experimental group | Duration, wk | Comparison | Outcome1 | Risk of bias2 |
|---|---|---|---|---|---|---|---|
| Probiotic intervention | |||||||
| Alisi (21) (2014) | Pediatric | 48 | VSL#3 (multispecies) | 16 | Placebo | Steatosis on US*, ALT, TGs, HOMA-IR, BMI | Low |
| Aller (22) (2011) | Adult | 30 | Lactobacillus bulgaricus and Streptococcus thermophilus | 12 | Placebo | ALT*, TB, BMI, weight, TC, TGs, FPG, HOMA-IR, IL-6, TNFα | Low |
| Behrouz (23) (2017) | Adult | 111 | Webber Naturals (multispecies) | 16 | Placebo | BMI, weight, FPG, insulin, HOMA-IR, leptin, % body fat, adiponectin | Low |
| Famouri (24) (2016) | Pediatric | 64 | Prokid (multispecies) | 12 | Placebo | Steatosis on US*, ALT, AST, BMI, weight, TC, WC | Low |
| Kobyliak (25) (2018) | Adult | 58 | Symbiter (multispecies) | 8 | Placebo | LSM*, FLI*, AST, ALT, TC, TNFα, IL-6, IL-8, IFNγ | Low |
| Monem (26) (2017) | Adult | 30 | Lactobacillus acidophilus | 4 | Usual care | ALT, AST, albumin, TB | High |
| Nabavi (27) (2014) | Adult | 72 | Probiotic yogurt (multispecies) | 8 | Placebo (conventional yogurt) | ALT, AST, TC, steatosis on US | Unclear |
| Sepideh (28) (2016) | Adult | 50 | Lactocare (multispecies) | 8 | Placebo | FPG, insulin, HOMA-IR, TNFα, IL-6, HbA1c | Unclear |
| Vajro (29) (2011) | Pediatric | 20 | Lactobacillus rhamnosus | 8 | Placebo | ALT*, steatosis on US, TNFα | Unclear |
| Synbiotic intervention | |||||||
| Asgharian (30) (2016) | Adult | 80 | Familact (multispecies + FOS) | 8 | Placebo | ALT*, AST*, steatosis on US, BMI, weight, CRP | Low |
| Bakhshimoghaddam (41) (2018) | Adult | 102 | Synbiotic yogurt (Bifidobacterium animalis + inulin) | 24 | Usual care or conventional yogurt | Steatosis on US*, ALT, AST, GGT, TC, FPG, insulin, GLP-2 | Unclear |
| Ekhlasi (31) (2016) | Adult | 30 | Protexin (multispecies + FOS) | 8 | Placebo | ALT*, AST, TC, TG, BMI, FPG, HOMA-IR, leptin, Apo A-1 | Low |
| Eslamparast (39) (2014) | Adult | 52 | Protexin (multispecies + FOS) | 28 | Placebo | ALT*, AST, TB, GGT, ALP, LSM, BMI, CRP, TNFα | Low |
| Ferolla (32) (2016) | Adult | 50 | Lactobacillus reuteri + inulin | 12 | Usual care | MRI PDFF*, ALT, AST, BMI, TC, TG, WC, uric acid | High |
| Javadi (33) (2017) | Adult | 36 | Bifidobacterium longum + Lactobacillus acidophilus + inulin | 12 | Placebo | ALT*, BMI, weight, TB, ALP | Low |
| Malaguarnera (34) (2011) | Adult | 66 | Bifidobacterium longum + FOS | 24 | Placebo | NAS*, ALT, AST, GGT, TB, TC, TG, FPG, insulin, CRP, TNFα | Low |
| Manzhalii (35) (2017) | Adult | 75 | Multispecies probiotic + FOS | 12 | Usual care | ALT*, AST, LSM, TC, TG, BMI | High |
| Mofidi (38) (2016) | Adult | 50 | Protexin (multispecies + FOS) | 28 | Placebo | CAP*, LSM, ALT, AST, FPG, HOMA-IR, TC, TG | Unclear |
| Sayari (40) (2018) | Adult | 138 | Familact (multispecies + FOS) | 16 | Placebo (sitagliptin in both groups) | BMI, FPG, ALT, AST, TC, TG | Low |
| Shavakhi (36) (2013) | Adult | 70 | Protexin (multispecies + FOS) | 24 | Placebo (metformin in both groups) | ALT*, AST*, steatosis on US*, BMI, FPG, TC, TG | Unclear |
| Wong (37) (2013) | Adult | 20 | Lepicol (multispecies + FOS) | 24 | Usual care | IHTG*, ALT, AST, BMI, FPG, LSM, TC, TG | High |
The prespecified primary outcome of each study is labeled with an asterisk (*). ALP, alkaline phosphatase; ALT, alanine aminotransferase; Apo, apolipoprotein; AST, aspartate aminotransferase; CAP, controlled attenuation parameter; CRP, C-reactive protein; FPG, fasting plasma glucose; FLI, fatty liver index; FOS, fructo-oligosaccharides; GGT, γ-glutamyltransferase; GLP-2, glucagon-like peptide 2; HbA1c, glycated hemoglobin; IFNγ, interferon γ; IHTG, intrahepatic triglyceride content; LSM, liver stiffness measurement; NAS, NAFLD activity score; PDFF, proton density fat fraction; TB, total bilirubin; TC, total cholesterol; TG, triglyceride; US, abdominal ultrasound; WC, waist circumference.
Assessed via the Cochrane Risk of Bias Tool.