Effect of Vitamin A and Calcium in Patients With Non-alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease (NAFLD) has become the most common liver disease at a global scale and is strongly associated with the obesity and metabolic syndrome . It is recognized as a hepatic manifestation of the metabolic syndrome, and characterized by lipid infiltration in the hepatocytes. NAFLD comprises a range of diseases from simple steatosis to non-alcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and may progress to hepatocellular carcinoma (HCC) .

The worldwide prevalence of NAFLD is estimated to be 24% while it is reported to have much higher incidence in patients with metabolic syndrome and type 2 diabetes (T2D) (5). The mortality rate and the number of liver transplantations owing to NAFLD and NASH are increasing, making it the second leading cause of liver transplant in the United States .

Tow significant metabolic abnormalities commonly linked to NAFLD are insulin resistance (IR) and increased supply of fatty acids to the liver . Chronic liver diseases (CLD), including NAFLD, are commonly associated with nutrient and vitamins deficiencies such as those of vitamins D and A (8,9).

Almost all studies documenting vitamin A status in metabolic syndrome (MetS) report reductions in serum retinol, retinoic acid, and/or β-carotene that are inversely correlated with MetS features, including obesity, insulin resistance, glucose intolerance, and hypertriglyceridemia . In line with these observations, inadequate serum retinol levels (<1.05 μmol/L) were found in 11-36% of morbidly obese adults with ultrasonography-proven NAFLD, and a significant association between low retinol levels and insulin resistance (IR) was found . Moreover, serum retinol levels were inversely associated with body mass and serum transaminases in patients with NAFLD, suggesting a link between retinol inadequacy and development of disease.

The liver plays a critical role in lipid metabolism by taking up serum free fatty acids (FFA) that are involved in the synthesis, storage, and transport of lipid metabolites. The accumulation of excess triacylglycerol (TG) within the liver due to the entry of excess FFA from the obese adipose tissue due to increased lipolysis leads to the development of non-alcoholic fatty liver diseases (NAFLD) .