Hepatic encephalopathy is a syndrome of impaired mental status and abnormal neuromuscular function which results from major failure of liver function. Important factors contributing to it are the degree of hepatocellular failure, portosystemic shunting, and exogenous factors such as sepsis and variceal bleeding.3 The pathogenesis of the syndrome is still uncertain, although current hypotheses include impaired hepatic detoxification of ammonia absorbed from the gut4 and an increase in aromatic amines, which are precursors for false transmitters in the brain.
Protein restriction in symptomatic patients with hepatic encephalopathy has been the cornerstone of treatment since the 1950s,2 yet there is no evidence that it has any clinical benefit.
This practice continues despite evidence showing that patients with stable cirrhosis have a higher protein requirement than normal, around 1.2 g/kg dry body weight to remain in positive balance.7
Protein energy malnutrition, defined by anthropometric criteria, may occur in 20-60% of patients with cirrhosis depending on the severity of the liver disease.8 It is a common finding, with causative factors which include anorexia, nausea, malabsorption, and a hypermetabolic state. Intake may be further reduced by use of unpalatable low protein diets, already restricted in sodium and fluid.
In 1997 the European Society for Parenteral and Enteral Nutrition published consensus guidelines recommending that the daily protein intake in patients with liver disease should, if possible, bearound 1.0- 1.5 g/kg depending on the degree of hepatic decompensation.7 The guidelines also recommended that in patients who were intolerant of dietary protein 0.5 g protein/kg should be used transiently and that the remainder of theirrequirements should be achieved by giving branched chain amino acids.9 Furthermore, aggressive enteral nutritional support of patients with alcoholic liver disease accelerates improvement without exacerbating hepatic encephalopathy.11 Taking smaller meals more often and eating a late evening meal also improve nitrogen balance without exacerbating hepatic encephalopathy.12 This may also be achieved with vegetable protein as opposed to animal proteins.13
