Protein-energy status and 15N-glycine kinetic study of child a cirrhotic patients fed low- to high-protein energy diets

In five male cirrhotic patients (Child A) and in four age- and sex-matched healthy control subjects, whole-body protein turnover was measured using a single oral dose of 15N-glycine as a tracer and urinary ammonia as end product. Subjects were studied in the fasting and feeding state, with different levels of protein and energy intake. The patients were underweight and presented lower plasma transthyretin and retinol-binding protein levels. When compared with controls, the kinetic studies showed patients to be hypometabolic in the fasting (D0) state and with the control diet [D1 = (0.85 g of protein/154 kJ) · kg−1 · day−1]. However, when corrected by body weight, the kinetic differences between groups disappeared, whereas the N-retention in the feeding state showed better results for the patients due mainly to their efficient breakdown decrease. When fed high-level protein or energy diets [D2 = (0.9 g protein/195 kJ) and D3 = (1.56 g protein/158 kJ) · kg−1 · day−1], the patients showed D0 = D1 = D2 < D3 for N-flux and (D0 = D1) < D3 (D2 is intermediary) for protein synthesis. Thus, the present data suggest that the remaining mass of the undernourished mild cirrhotic patients has fairly good protein synthesis activity and also that protein, rather than energy intake, would be the limiting factor for increasing their whole-body protein synthesis.