Elimination and metabolism of a fat emulsion containing medium chain triglycerides (lipofundin MCT 10%)

Medium chain triglycerides (MCT) are supposed to be advantageous on account of rapid energy supply in parental nutrition. However, data on the elimination rate of MCT-containing emulsions during an intravenous fat-tolerance test (IVFTT) are scarce. We performed this test (0.1 g lipid/kg body weight) in 18 young healthy volunteers (nine females and nine males) using Lipofundin MCT 10% (50% MCT; egg phospholipids as emulsifier). Our results indicate that both elimination and metabolization of the emulsion are fast: a prompt decrease of light-scattering index and of triglyceride concentrations in serum, an immediate appearance of post-load fatty acids and of beta-hydroxybutyrate were observed. This was in good agreement with the findings obtained during 6-hr infusions in the same probands. Fractional elimination rates k2 obtained from light-scattering indices are 7.29 +/- 2.73%/min in males and 11.59 +/- 3.38%/min in females, indicating a higher removal capacity in women. In the same subjects, the corresponding k2 values for Lipofundin S 10% (containing only long chain triglycerides) were higher, reflecting an elimination rate that is faster due to the use of soya bean phospholipids as emulsifier. In comparison, k2 values based on the course of the triglyceride concentrations are generally lower.