Long-term abuse of a high-carbohydrate diet is as harmful as a high-fat diet for development and progression of liver injury in a mouse model of NAFLD/NASH

Objectives: Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disease globally. It is caused by a complex network of factors, including diet. The hallmark of NAFLD is the benign accumulation of triacylglycerols, however, this condition may worsen into non-alcoholic steatohepatitis (NASH), a more severe form associated with inflammation and fibrosis. Currently, no therapies are available, and diet modifications are the only strategy. Although there is increasing evidence emerging about how an abuse of carbohydrates could be involved in the progression of liver injury, a comprehensive understanding of the damage induced by an enriched carbohydrate diet is still far from complete. The aim of this study was to investigate and compare the effects of a low-fat/high-carbohydrate diet (LF-HCD) with high-fat (HFD) and standard (SD) diets in a nutritional mouse model of NAFLD/NASH. Methods: Histologic, real-time polymerase chain reaction, and immunohistochemical evaluations were performed. Results: The results showed that the prolonged abuse of both LF-HCDs and HFDs induced a significant increase in hepatic steatosis, inflammation, and fibrosis scores compared with SD. At the same time, both LF-HCDs and HFDs led to significant increases in the expression of the molecules involved in the progression of NAFLD that we assessed (perilipin, CD68, TGF-β1, CTGF, leptin, leptin receptor, and α-SMA). Conclusions: The present study highlighted that the simple substitution of fats with carbohydrates is not a proper strategy to prevent or mitigate the progression of NAFLD/NASH. Further studies are required to define the best nutritional strategy to prevent NAFLD and its related metabolic syndrome.