Historically, it was assumed that dietary deficiencies were the major reason of developing liver disease in alcoholics. However, due to the overall improvement of nutrition of the population, more stress is given on secondary malnutrition. Evidences demonstrate hepatotoxic effects of ethanol which are attributed to redox changes produced by reduced nicotinamide adenine dinucleotide (NADH) generated through the alcohol dehydrogenase (ADH) pathway. Besides, ethanol can also be oxidized by a microsomal ethanol oxidizing system (MEOS) including cytochrome P-450; this novel discovered ethanol-inducible cytochrome P-450 (P-450IIE1) is implicated in ethanol metabolism, tolerance, energy, and the selective hepatic perivenular toxicity of numerous xenobiotics. However, induction of P-450 also causes reduction and increased toxicity of nutritional factors such as vitamin A. It has been reported that alcoholics have a very low hepatic concentration of vitamin A, even at the early fatty-liver stage. While conducting experimental studies, ethanol administration depressed hepatic levels of vitamin A which did not improved even after administration  with diets containing large amounts of the vitamin, suggestive of accelerated microsomal degradation via newly discovered microsomal pathways of retinol metabolism, induced by either ethanol or drug administration.  Moreover, when ethanol are co-administered with other drugs, hepatic reduction of vitamin A got worsened causing common clinical manifestations. Additionally, an interrelationship existed between hepatic retinoid depletion, lysosomal lesions and decreased detoxification of chemical carcinogens. 

Therefore, alcoholics with liver disease should be supplemented with vitamin A to prevent these deleterious effects as well as to rectify night blindness and sexual inadequacies. However, excessive amount of vitamin A can be hepatotoxic, an effect aggravated by long-term ethanol consumption. These adverse effects can cause prominent morphologic and functional modification in the mitochondria with leakage of mitochondrial enzymes, hepatic necrosis, and fibrosis. Thus, although vitamin A therapy and other nutritional factors including proteins has positive effects, it should be carefully supplemented in alcoholics who have increased demand for such nutrients and increased susceptibility to their adverse effects. 

Source: Lieber CS. Alcohol, liver, and nutrition. J Am Coll Nutr. 1991 Dec;10(6):602-32.