Background: Non-alcoholic fatty liver disease comprises a spectrum of diseases ranging from simple steatosis to non-alcoholic steatohepatitis, fibrosis, and cirrhosis. Probiotics have been proposed as a treatment option because of their modulating effect on the gut flora that could influence the gut-liver axis.
Objectives: To evaluate the beneficial and harmful effects of probiotics for non-alcoholic fatty liver disease and/or steatohepatitis.
Search strategy: We searched The Cochrane Hepato-Biliary Group Controlled Trials Register (July 2006), the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 2, 2006), MEDLINE (1966 to May 2006), and EMBASE (1980 to May 2006). No language restrictions were applied.
Selection criteria: Randomised clinical trials evaluating probiotic treatment in any dose, duration, and route of administration versus no intervention, placebo, or other interventions in patients with non-alcoholic fatty liver disease. The diagnosis was made by history of minimal or no alcohol intake, imaging techniques showing hepatic steatosis and/or histological evidence of hepatic damage, and by exclusion of other causes of hepatic steatosis.
Data collection and analysis: We had planned to extract data in duplicate and analyse results by intention-to-treat.
Main results: No randomised clinical trials were identified. Preliminary data from two pilot non-randomised studies suggest that probiotics may be well tolerated, may improve conventional liver function tests, and may decrease markers of lipid peroxidation.
Authors' conclusions: The lack of randomised clinical trials makes it impossible to support or refute probiotics for patients with non-alcoholic fatty liver disease and non-alcoholic steatohepatitis.