Patients with chronic liver disease have a high risk to malnutrition. Proper nutrition should be provided through a proper nutritional assessment. Enteral nutrition is recommended as a nutritional supplement because it maintains the intestinal mucosa, reduces infectious complications, is less costly than parenteral nutrition, and is more physiological to use intestine. The purpose of this review is to define the nutritional deficiencies of patients with liver disease and to show the indications for enteral nutrition and to validate the efficacy of enteral nutrition. According to the various guidelines and researches, enteral nutrition is used as a solution to the nutritional problems caused by patients with liver disease. The optimal enteral formula will be selected on the nutritional problems. It is expected that the enteral nutrition will reduce especially postoperative complications, intraperitoneal complications, pneumonia, and wound infection. The enteral nutrition for patients with chronic liver disease should be actively implemented.

Liver disease and nutritional status are known to affect each other. When liver disease is severe, patients become more malnourished and have a worse prognosis. Adequate nutritional support for patients with liver diseases can improve a patient’s condition and prognosis. In acute liver failure, malnutrition is uncommon, and the disease prognosis is determined within a short time. Patients with acute liver failure may survive and recover if they receive a transplant. Considerations should be given to the management of glucose intolerance and hyperammonemia. However, well-designed clinical trials are still lacking until now. In the case of liver cirrhosis, malnutrition may occur due to a variety of causes, and as in other diseases, oral or enteral nutrition is preferred to parenteral nutrition. Even if esophageal varices are present, it is possible to install a feeding tube. However, in the presence of ascites, PEG (percutaneous endoscopic gastrostomy) becomes contraindicated due to risk of complications. Calorie intake of 30~35 Kcal/kg/day and protein intake of 1.2 to 1.5 g/kg/day are appropriate. Protein restriction should not be necessary unless hepatic encephalopathy is severe. Late evening snacking and intake of branched chain amino acids can be helpful.

Lipids are structural components of cellular membrane and functional components exerting an important role in different metabolic pathways through regulation of cell signaling and metabolic homeostasis. Although the human body can synthesize some fatty acids, essential fatty acids (EFA) should be exogenously provided. Parenteral nutrition (PN) can be utilized to provide EFA for patients without normal gastrointestinal functions and those at risk of malnutrition. Parenteral lipids provide more energy-dense nutrition in a reduced volume and prevent EFA deficiency. However, prolonged PN with lipid emulsions is associated with metabolic complications including PN-associated liver disease. Currently available parenteral lipid emulsions provide various combinations of soybean oil, fish oil, olive oil and medium-chain triglycerides. The effects of parenteral lipid emulsions on the lipid nutrition status and PN-associated complications vary depending on the type and dosages of main oil sources used in parenteral lipid solutions. Therefore, understanding the composition, metabolism, and functional effects of lipids can be helpful in considering their clinical applications in PN.