Background: Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the world. Oral administration of synbiotic has been proposed as an effective treatment of NAFLD because of its modulating effect on the gut flora, which can influence the gut-liver axis.

Objective: The objective was to evaluate the effects of supplementation with synbiotic on hepatic fibrosis, liver enzymes, and inflammatory markers in patients with NAFLD.

Design: In a randomized, double-blind, placebo-controlled clinical trial conducted as a pilot study, 52 patients with NAFLD were supplemented twice daily for 28 wk with either a synbiotic or a placebo capsule. Both groups were advised to follow an energy-balanced diet and physical activity recommendations.

Results: At the end of the study, the alanine aminotransferase (ALT) concentration decreased in both groups; this reduction was significantly greater in the synbiotic group. At the end of the study, the following significant differences [means (95% CIs)] were seen between the synbiotic and placebo groups, respectively: ALT [-25.1 (-26.2, -24) compared with -7.29 (-9.5, -5.1) IU/L; P < 0.001], aspartate aminotransferase [-31.33 (-32.1, -30.5) compared with -7.94 (-11.1, -4.8) IU/L; P < 0.001], γ-glutamyltransferase [-15.08 (-15.5, -14.7) compared with -5.21 (-6.6, -3.9) IU/L; P < 0.001], high-sensitivity C-reactive protein [-2.3 (-3, -1.5) compared with -1.04 (-1.5, -0.6) mmol/L; P < 0.05], tumor necrosis factor-α [-1.4 (-1.7, -1.1) compared with -0.59 (-0.8, -0.3) mmol/L; P < 0.001], total nuclear factor κ-B p65 [-0.016 (-0.022, -0.011) compared with 0.001 (-0.004, -0.007) mmol/L; P < 0.001], and fibrosis score as determined by transient elastography [- 2.98 (-3.6, -2.37) compared with -0.77 (-1.32, -0.22) kPa; P < 0.001].

Conclusions: Synbiotic supplementation in addition to lifestyle modification is superior to lifestyle modification alone for the treatment of NAFLD, at least partially through attenuation of inflammatory markers in the body. Whether these effects will be sustained with longer treatment durations remains to be determined.