[Randomized study comparing long-chain (LCT) and medium-chain (MCT) triglycerides as caloric carriers in...

The aim of the study was to investigate the effect of a new 20% fat emulsion, containing 50% MCT and 50% LCT in comparison to a 20% fat emulsion containing only LCT, in the postoperative period. The possible influence on nitrogen loss, protein synthesis and fat metabolism was estimated. 20 patients after elective colon surgery were included in the trial. Parenteral nutrition was carried out for 5 days with two isonitrogenic and isocaloric nutritional regimens including either MCT/LCT or only LCT fat emulsions. Fat emulsions were administered over a period of 12 h with a total fat supply rate of 0.12 g/kg B.W./h. Blood samples for determination of protein synthesis, triglyceride and ketone bodies were taken under fat infusion as well as before and after infusion. 24-h urine samples were taken to measure nitrogen balance. Our results showed no difference in protein levels between the MCT- and LCT group. The 5-day nitrogen balance showed a significant increase in the MCT group (p less than 0.05, Mann-Whitney U-test). At the end of the infusion period triglyceride levels in the MCT group (mean value 244 +/- 15 mg%) differed significantly compared to the LCT group (m = 190 +/- 24 mg%). 2 h later triglycerides in both groups fell to basal levels. beta-Hydroxybutyrate (beta-HB) and aceto acetate (Ac-ac) concentrations showed significant differences between both groups. After 12 h infusion the MCT group had a mean level of 210 mumol/l beta-HB and 180 mumol/l Ac-ac vs. 90 mumol/l beta-HB and 120 mumol/l Ac-ac in the LCT group.(ABSTRACT TRUNCATED AT 250 WORDS)