Factors influencing essential fatty acid requirement in total parenteral nutrition (TPN).

Twenty patients, after major injuries or elective abdominal surgery, were studied with respect to essential fatty acids in total serum and lipoprotein fractions. The regimen of total parenteral nutrition was altered in its content of energy, carbohydrates or fat. In all patients the linoleic acid levels decreased and the 20:3/20:4 ratio increased. Serum low density lipoproteins developed remarkable alterations of the biochemical composition and of morphology by electronmicroscopy. The degree of these alterations depended on the kind of illness, the amount of carbohydrates infused, special hormonal situation due to surgery and linoleic acid supply. As a consequence of these results, the supply of a sufficient amount of linoleic acid should be considered in every case of total parenteral nutrition.