Nonalcoholic Fatty Liver Disease (NAFLD) is the hepatic manifestation of metabolic syndrome, and its rising prevalence parallels the rise in obesity and diabetes. Historically thought to result from overnutrition and sedentary lifestyle, recent evidence suggests that diets high in sugar (from sucrose and/or high fructose corn syrup (HFCS)) not only increases the risk for NAFLD, but also, nonalcoholic steatohepatitis (NASH).
Here we review the experimental and clinical evidence that fructose precipitates fat accumulation in the liver, due to both increased lipogenesis and impaired fat oxidation. Recent evidence suggests that the predisposition to fatty liver is linked with metabolism of fructose by fructokinase C, resulting in ATP consumption, nucleotide turnover and uric acid generation that mediate fat accumulation.
Alterations in gut permeability, microbiome, and associated endotoxemia contributes to the risk of NAFLD and NASH. Early clinical studies suggest that reducing sugary beverages and total fructose intake, especially from added sugars, may have a significant benefit on reducing hepatic fat accumulation.