title: Minimum protein requirements in liver cirrhosis determined by nitrogen balance measurements at three levels of protein intake.
abstract: Nitrogen balance at three levels of protein intake was measured in eight patients with cirrhosis of the liver; moreover, at each level of protein intake, the effects on nitrogen balance of branched-chain amino-acid enriched protein and natural protein were compared. From these nitrogen balance data, minimum protein requirements were calculated by linear regression analysis. The patients were in a negative nitrogen balance on a 40 g protein diet (-0.75 +/- 0.15 gN.), and in positive nitrogen balance on 60 g (+1.23 +/- 0.22 gN.) or 80 g of protein per day (+2.77 +/- 0.20 g N.). Their mean minimum protein requirement (48 +/- 5 g of protein/day or 0.75 g/kg/day) is higher than expected in healthy people; the safe level of protein intake (mean + 2 sd) is 58 g per day or 1.2 g/kg/day. Nitrogen balances and protein requirements were not different on branched-chain amino-acid enriched diets. The physical condition of the patients improved when they came into positive nitrogen balance; the higher rates of protein intake were well tolerated without onset of encephalopathy. We conclude that protein requirements are elevated in cirrhosis of the liver; diets supplying less than 60 g of protein per day should not be prescribed in long term treatment of cirrhotic patients.
authors.affiliation: Department of Internal Medicine II, University Hospital Rotterdam-Dijkzigt D419, 3015 GD Rotterdam, The Netherlands.
authors.forename: G R
authors.initials: GR
authors.lastname: Swart
authors.forename: J W
authors.initials: JW
authors.lastname: van den Berg
authors.forename: J K
authors.initials: JK
authors.lastname: van Vuure
authors.forename: T
authors.initials: T
authors.lastname: Rietveld
authors.forename: D L
authors.initials: DL
authors.lastname: Wattimena
authors.forename: M
authors.initials: M
authors.lastname: Frenkel