Background: About 25% of the global population suffers from non-alcoholic fatty liver disease (NAFLD), making it the most prevalent form of liver disease. One form of NAFLD, nonalcoholic steatohepatitis (NASH), can ultimately lead to cirrhosis, hepatocellular carcinoma (HCC), and mortality. The most common causes of fatty liver disease are being overweight or obese, having insulin resistance, leading an inactive lifestyle, consuming a high-fat diet and having a family history of the condition. The pathogenesis of NAFLD is associated with a weaker intestinal barrier caused by an altered gut microbiota, which exposes the host to bacterial components and triggers immunological defense and inflammation pathways via toll-like receptor signalling, ultimately leading to the development of NASH. The objective of the present review article is to discuss the risk factors and pathophysiological pathways that lead to NAFLD. Development: PubMed, Google scholar and Science direct were searched using the following keywords: Steatohepatitis, Steatosis, Hepatocellular carcinoma, Metabolic syndrome, Dysbiosis and Non-alcoholic fatty liver disease. The authors also screened references from the relevant literature, including all the identified studies and reviews, only the most recent or complete study was included between December 2002 and April 2021. Documents in a language apart from English have been excluded as sources for interpretation was not found. Papers apart from main scientific studies had been excluded: documents unavailable as total written text, conversation, conference abstract papers and dissertations.
Conclusion: Globally, NAFLD is the most prevalent form of chronic liver disease. The pathophysiology of NAFLD is complex and requires the interaction of multiple factors. Metabolic syndrome, insulin resistance, unhealthy dietary habits and gut microbiota play major roles for the development of NAFLD.