Fatty Liver: It is not just about fat - Nutritional impact on non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) has become a worldwide epidemic, which is associated with obesity, diabetes mellitus and cardiovascular disease. NAFLD covers a broad spectrum of disorders that range from simple lipid accumulation in the liver (steatosis) to oxidative stress and inflammation (steatohepatitis). There is currently no approved treatment for this disease. Chronic consumption of high energy diets (i.e. diet rich in fat content) promotes the development of NAFLD. Dietary supplementation of vitamins or phenolic compounds has been suggested to be a beneficial strategy for NAFLD management. Folic acid is a water soluble B vitamin that has been demonstrated to have lipid-lowering and anti-oxidant effects. Tyrosol is one of the major phenolic compounds in olive oil and wine which are two unique dietary staples in diet. We investigated the impact of dietary intervention on hepatic metabolism and oxidative stress in a rodent model with NAFLD. Male C57BL/6 mice were fed a low-fat diet (10% kcal of fat) or a high fat diet (60% kcal of fat) for 5-12 weeks. Feeding mice with a high-fat diet stimulated rapid body weight gain and induced NAFLD phenotype with hepatic lipid accumulation, hyperglycaemia, increased oxidative stress and proinflammatory cytokine expression. Supplementation of folic acid and natural compounds (i.e. tyrosol) could alleviate high-fat diet induced hepatic lipotoxicity. The beneficial effects of dietary intervention were mediated through regulation of endogenous lipid biosynthesis, homocysteine-hydrogen sulphide metabolism as well as restoration of redox balance. Dietary interventions may have important
clinical implications in NAFLD management.