[Future perspectives in parenteral nutrition]

Some of the future perspectives of parenteral nutrition will most likely be related to the possibilities of improving the infusion solutions used. There are studies indicating that intravenous amino acid mixtures may produce better biochemical and clinical effects either by increasing the content of histidin, arginine, tyrosine, cysteine/cystine and branched chain amino acids or by adding glutamine, ornithin, ornithin-ketoglutaric acid, taurine and glutathion. Several possibilities of improving the intravenous fat emulsions have been studied and discussed. The use of medium chain fatty acid glycerides (MCT) instead of long chain fatty acid glycerides (LCT) may be of some value. Physical mixtures of LCT and MCT have been studied. Glycerides of both medium chain and long chain fatty acids of the same glycerol molecule ('structured lipids') have also been investigated. The omega-3-fatty acids (alfalinolenic, eicosapentaenoic and docosahexaenoic acid) have unique biochemical properties which may be beneficial in various clinical situations when parenteral nutrition is indicated. Intravenous fat emulsions containing triglycerides of these fatty acids are now being extensively investigated. The omega-3-fatty acids will change the pattern of eicosanoids formed, reduce the tendency to platelet aggregation, increase the resistance to endotoxins, and reduce the viscosity of the blood. Triglycerides of gamma linolenic acid have been considered to be of value in situations when there may be a reduced activity of delta-6-desaturase to transform linoleic acid to arachidonic acid. Many other known (carnitine, non-protein sources, vitamins and trace elements) or unknown nutrients may be found to be useful in order to improve the infusion solutions used in parenteral nutrition.(ABSTRACT TRUNCATED AT 250 WORDS)