Published online May 18, 2017. doi: 10.4254/wjh.v9.i14.667
Peer-review started: October 31, 2016
First decision: December 1, 2016
Revised: February 21, 2017
Accepted: April 23, 2017
Article in press: April 24, 2017
Published online: May 18, 2017
To investigate the plasma amino acid response and tolerance to normal or high protein meals in patients with cirrhosis.
The plasma amino acid response to a 20 g mixed protein meal was compared in 8 biopsy-proven compensated cirrhotic patients and 6 healthy subjects. In addition the response to a high protein meal (1 g/kg body weight) was studied in 6 decompensated biopsy-proven cirrhotics in order to evaluate their protein tolerance and the likelihood of developing hepatic encephalopathy (HE) following a porto-caval shunt procedure. To test for covert HE, the “number connection test” (NCT) was done on all patients, and an electroencephalogram was recorded in patients considered to be at Child-Pugh C stage.
The changes in plasma amino acids after a 20 g protein meal were similar in healthy subjects and in cirrhotics except for a significantly greater increase (P < 0.05) in isoleucine, leucine and tyrosine concentrations in the cirrhotics. The baseline branched chain amino acids/aromatic amino acids (BCAA/AAA) ratio was higher in the healthy persons and remained stable-but it decreased significantly after the meal in the cirrhotic group. After the high protein meal there was a marked increase in the levels of most amino acids, but only small changes occurred in the levels of taurine, citrulline, cysteine and histidine.The BCAA/AAA ratio was significantly higher 180 and 240 min after the meal. Slightly elevated basal plasma ammonia levels showed no particular pattern. Overt HE was not observed in any patients.
Patients with stable liver disease tolerate natural mixed meals with a standard protein content. The response to a high protein meal in decompensated cirrhotics suggests accumulation of some amino acids but it did not precipitate HE. These results support current nutritional guidelines that recommend a protein intake of 1.2-1.5 g/kg body weight/day for patients with cirrhosis.
Core tip: In this study we investigated the plasma amino acid response to standard and high protein meals in patients with liver cirrhosis and looked for evidence of protein intolerance by testing for the presence of either covert or overt hepatic encephalopathy. We sought to improve on previous methodology by selecting a more homogeneous group of patients with biopsy proven cirrhosis, and by using natural mixed protein meals at two protein levels: A standard (20 g) meal and a high (1 g/kg per body weight) protein meal. We found small differences in the plasma amino acid changes after the standard protein meal but there were marked increments in most amino acids after the high protein meal. Noteworthy no patient showed overt clinical sings of encephalopathy and minor electroencephalo-graph changes were seen in only one patient after the high protein meal. These results present experimental evidence to support current nutritional guidelines for patients with cirrhosis.