Preferential use of branched-chain amino acids as an energy substrate in patients with liver cirrhosis.

We analyzed basal energy metabolism in 20 healthy volunteers and 41 cirrhotic patients by indirect calorimetry. Subjects were then given either glucose, branched-chain amino acids (BCAA) or fatty acids as an energy substrate. Resting energy expenditure (REE), nonprotein respiratory quotient (npRQ), and oxidation rates of glucose (% CHO), protein (% PRO) and fat (% FAT) were analyzed. REE and %FAT were significantly higher and % CHO and %PRO were significantly lower in cirrhosis than in controls. These changes correlated with disease severity. Glucose and BCAA were utilized efficiently as energy substrates and reduced %FAT in cirrhosis. Energy efficacy (increased energy expenditure/energy equivalent of the supplemented nutrient) was significantly higher in BCAA (96 +/- 16%) than in glucose (41 +/- 8%) (p<0.01) and fatty acids (27 +/- 13%) (p<0.05). Patients with cirrhosis have an increased energy requirement. BCAA seems to be the preferred substrate to meet this demand, because its energy efficacy is higher than glucose or fatty acids in cirrhosis.