Effect of dietary protein against excess vitamin A induced hepatotoxicity in rats

Abstract

Vitamin A deficiency is a serious nutritional deficiency disease. In most cases vitamin A deficiency is associated with protein malnutrition. Excess vitamin A cannot be transported for want of transport protein. We aimed to investigate the quantity of protein required in diet to protect excess vitamin A fed hepatotoxicity in rats. Normal and excess amount of vitamin A (4000 IU/kg and 40000 IU/kg)) with three different levels of dietary protein (6%, 18% and 30%) were administered orally for 30 consecutive days in rats. In low protein diet vitamin A level significantly increased in liver and decreased in plasma and, lipids level were found to be high in liver. Administration of excessive doses of vitamin A resulted in significant decrease in the levels of serum and liver RBP. Excess vitamin A in low protein state significantly induced oxidative stress in the liver, leading to increased serum levels of liver enzyme markers aminotransferases, total and direct bilirubin. Lipid remains in liver for want of transport protein and aggravates the formation of fatty liver. Both lipids and lipoprotein levels are also measured to assess the liver function in hypervitaminosis; a state where abnormally high storage levels of vitamins can lead to toxic symptoms.