Nutritional Risk Factors in the Pathogenesis of Parenteral Nutrition-Associated Liver Disease

Purpose of Review: Parenteral nutrition has been a lifesaving therapy for individuals who cannot sustain adequate oral or enteral nutrient intake to maintain fluid, electrolyte, and nutrient balance. Nonetheless, parenteral nutrition can lead to an increased risk of complications, such as parenteral nutrition-associated liver disease (PNALD). The pathogenesis of PNALD has been associated with multiple risk factors, such as longer duration, reduced small bowel length, decreased enteral intake, and bacterial infections. Nutritional risk factors also play an important role in the development of PNALD. This review presents several nutrient deficiencies and excesses that have been associated with PNALD. Recent Findings: Deficiencies in certain nutrients (amino acids, essential fatty acids, enteral intake), excesses of certain nutrients (calories, carbohydrates, lipids), types of lipid emulsions, and mineral toxicities (aluminum, copper, manganese) have been associated with PNALD. Strategies to address PNALD require correction of these risk factors. The use of newer mixed lipid emulsions (including soybean, medium-chain triglycerides, olive oil, and fish oil) may also have less hepatotoxicity than traditional soybean oil-based lipid emulsions. Summary: Knowledge of nutritional risk factors for PNALD will help the clinician in the systematic evaluation and treatment of these specific risk factors. Moreover, an understanding of their effects guides the balance between addressing the patient’s nutritional needs and reducing the risk of PNALD.