Effects of Extra-Carbohydrate Supplementation in the Late Evening on Energy Expenditure and Substrate Oxidation in Patients With Liver Cirrhosis

Abstract

Background: The purpose of this study was to demonstrate the effects of extra-carbohydrate supplementation before bedtime on energy metabolism and substrate oxidation in patients with liver cirrhosis. Methods: Sixteen cirrhotic patients and eight control subjects were included in this study. To compare the effect of energy metabolism and substrate oxidation with or without a bedtime snack, indirect calorimetry was assessed at 7 to 8 AM after overnight fasting, following either dinner (6 PM) or a bedtime snack (11 PM) the evening before. The bedtime snack contained about 50 g of carbohydrate. The energy expenditure and substrate oxidation were calculated from the indirect calorimetry measurement and 24-hour urinary nitrogen excretion. Results: In those who fasted since dinner, the respiratory quotient (RQ) was significantly lower in cirrhotic patients than in control subjects. Also, the energy utilized by cirrhotic patients was derived primarily from fat oxidation (58%), whereas the main energy source for controls was carbohydrate (55%). An extra-carbohydrate supplement before bedtime did not influence the indirect calorimetry measurement in the controls, but there were significant increases in both RQ and carbon dioxide production (VCO₂) in cirrhotic patients. The extra-carbohydrate supplementation did not significantly change the absolute resting energy expenditure utilization in control subjects; however, the utilization of carbohydrate significantly increased with a decrease in fat and protein oxidation in the cirrhotic patients. Conclusions: These preliminary data suggest that extra-carbohydrate supplementation before bedtime can shorten nocturnal fasting with a more economic fuel utilization and effectively diminish fat and protein oxidation in cirrhotic patients. (Journal of Parenteral and Enteral Nutrition 21:96-99, 1997)