[Clinical studies with fat emulsions containing LCT and MCT]

In an effort to supply energy carriers with a high utilization rate specifically in parenteral nutrition during postaggression metabolism, fat emulsions were developed containing long- and medium-chained triglycerides in a 1:1 ratio. The special advantage of the medium-chained fatty acids is, among other things, their low rate of accumulation and high oxidation rate in the organism. Using a graduated schedule, intensive-care patients who were being parenterally fed exclusively were administered either an MCT/LCT mixture or an LCT emulsion alone as a bolus injection and later continuously. Among other things, the behavior of the triglyceride concentrate and the individual fatty acids in serum and of individual lipid fractions, as well as the effect on various parameters of carbohydrate and fat metabolism, were measured. In addition, the oxidation rate of an MCT/LCT emulsion labelled with 13C was measured. The results of the comparative lipid studies were compared. The expected result-that the oxidation rate of medium-chained triglycerides exceeds that of long-chained triglycerides-was confirmed. It was surprising that the median oxidation rate with a continuous fat supply within a complete nutrition program was only 32 +/- 6.8%. Why some patients showed higher triglyceride levels with the MCT/LCT emulsion than with the supply of LCT alone is still unclear. It remains to be investigated whether the rapid splitting of medium-chained triglycerides leads to a temporary loss of activity of the lipoprotein lipase accompanied by a rise in triglycerides in serum. More research will be necessary before we know what role MCT/LCT emulsions will play in future. Such an emulsion would possibly be suitable in severely injured patients, whereby the MCT portion could preferentially supply the organism with energy carriers and the long-chained triglycerides structural components.