Effects of enteral carbohydrates on de novo lipogenesis in critically ill patients.
BACKGROUND
Conversion of glucose into lipid (de novo lipogenesis; DNL) is a possible fate of carbohydrate administered during nutritional support. It cannot be detected by conventional methods such as indirect calorimetry if it does not exceed lipid oxidation.


OBJECTIVE
The objective was to evaluate the effects of carbohydrate administered as part of continuous enteral nutrition in critically ill patients.


METHODS
This was a prospective, open study including 25 patients nonconsecutively admitted to a medicosurgical intensive care unit. Glucose metabolism and hepatic DNL were measured in the fasting state or after 3 d of continuous isoenergetic enteral feeding providing 28%, 53%, or 75% carbohydrate.


RESULTS
DNL increased with increasing carbohydrate intake (f1.gif" BORDER="0"> +/- SEM: 7.5 +/- 1.2% with 28% carbohydrate, 9.2 +/- 1.5% with 53% carbohydrate, and 19.4 +/- 3.8% with 75% carbohydrate) and was nearly zero in a group of patients who had fasted for an average of 28 h (1.0 +/- 0.2%). In multiple regression analysis, DNL was correlated with carbohydrate intake, but not with body weight or plasma insulin concentrations. Endogenous glucose production, assessed with a dual-isotope technique, was not significantly different between the 3 groups of patients (13.7-15.3 micromol * kg(-1) * min(-1)), indicating impaired suppression by carbohydrate feeding. Gluconeogenesis was measured with [(13)C]bicarbonate, and increased as the carbohydrate intake increased (from 2.1 +/- 0.5 micromol * kg(-1) * min(-1) with 28% carbohydrate intake to 3.7 +/- 0.3 micromol * kg(-1) * min(-1) with 75% carbohydrate intake, P: < 0. 05).


CONCLUSIONS
Carbohydrate feeding fails to suppress endogenous glucose production and gluconeogenesis, but stimulates DNL in critically ill patients.
Schwarz
J M
JM
Department of Nutritional Sciences, University of California, Berkeley.
Chioléro
R
R
Revelly
J P
JP
Cayeux
C
C
Schneiter
P
P
Jéquier
E
E
Chen
T
T
Tappy
L
L
D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000032:analysis; D002153:Calorimetry, Indirect; D050260:Carbohydrate Metabolism; D002241:Carbohydrates / Q000008:administration & dosage; D002851:Chromatography, High Pressure Liquid; D003422:Critical Care / Q000379:methods; D004750:Enteral Nutrition / Q000379:methods*; D005227:Fatty Acids / Q000097:blood; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D005934:Glucagon / Q000097:blood; D005943:Gluconeogenesis; D005947:Glucose / Q000096:biosynthesis / Q000378:metabolism; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000032:analysis; D007700:Kinetics; D008055:Lipids / Q000096:biosynthesis*; D008099:Liver / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011446:Prospective Studies; D011863:Radioimmunoassay; D011897:Random Allocation; D012044:Regression Analysis; D014280:Triglycerides / Q000097:blood
D001786:Blood Glucose; D002241:Carbohydrates; D005227:Fatty Acids; D007328:Insulin; D008055:Lipids; D014280:Triglycerides; D005934:Glucagon; D005947:Glucose; D006854:Hydrocortisone