Restricting Protein Intake not Beneficial

The Diagnosis and Treatment of Minimal Hepatic Encephalopathy by Dr. med. Tianzuo Zhan, Prof. Dr. med. Dr. h.c. med. Wolfgang Stremmel in volume 10/2012

Zhan and Stremmel correctly draw attention to minimal hepatic encephalopathy (MHE), a frequently unrecognized complication of cirrhosis. They highlight the dilemma that restriction of dietary protein intake further reduces muscle mass in patients who are already severely malnourished. In the section on nutritional therapy, however, the authors fail to make clear statements. The European Society for Clinical Nutrition and Metabolism (Europäische Gesellschaft für Stoffwechselforschung und klinische Ernährung, ESPEN) guideline recommending a protein rich diet is based on evidence from randomized controlled trials (1) and should not be dismissed. Even in patients with recurrent encephalopathy, protein restriction—as previously recommended—is not beneficial (2). The often reiterated recommendation of protein restriction is based on a collection of cases reported by Sherlock and colleagues in 1954. Here they described a selected subgroup of five patients with cirrhosis and encephalopathy, four of whom suffered from portal vein thrombosis and two of whom were treated with ammonium chloride as a diuretic. „Meat intoxication“ as a precipitating factor of hepatic encephalopathy is a rare event nowadays and listing excessive protein intake as item number 2 in the box showing precipitating factors is not appropriate. Infections are far more important in that respect and should be systematically and rapidly sought for and treated; indeed, infections should be at the top of the list.

Furthermore, an effect of lactulose on ammonia generation from the glutamine metabolism of the small intestinal mucosa can only be exerted by small bowel evacuation but not by a specific effect on glutamine uptake (3). The work of Egberts and Schomerus on the effect of branched-chain amino acids on driving capacity seems to have escaped the authors’ attention when compiling the list of randomized controlled trials.

DOI: 10.3238/arztebl.2012.0502a

Prof. Dr. med. Mathias Plauth

Städtisches Klinikum Dessau

Conflict of interest statement

The authors has received honoraria for acting as an expert adviser from Baxter Advisory Board, lecture honoraria from Falk Foundation, Nestlé, Baxter, Roche, and Ardeypharm, and honoraria for conducting several clinical phase II/III trials.

References

1. Kearns P, Young H, Garcia G, et al.: Accelerated improvement of alcoholic liver disease with enteral nutrition. Gastroenterology 1992; 102: 200–5.

2. Córdoba J, López-Hellín J, Planas M, et al.: Normal protein for episodic hepatic encephalopathy: results of a randomized trial. J Hepatol 2004; 41: 38–43.

3. Plauth M, Raible A, Graser TA, et al.: Lactulose or paromomycin do not affect ammonia generation in the isolated perfused rat small intestine. Z Gastroenterol 1994; 32: 141–5.

4. Zhan T, Stremmel W: The diagnosis and treatment of minimal hepatic encephalopathy. Dtsch Arztebl Int 2012; 109(10): 180–7.