Serum fatty acid concentrations in patients on postoperative parenteral nutrition with and without fat.

To examine changes in fatty acid composition of serum lipids, sixteen patients with gastric cancer were maintained on total parenteral nutrition (TPN) or intravenous feeding immediately after total gastrectomy. Subjects receiving no fat showed decreases in linoleic acid, linolenic acid and arachidonic acid and increases in palmitoleic acid and oleic acid, whereas those receiving fat emulsion showed no detectable changes. Decrease in the linoleic acid content was greater in subjects on a higher carbohydrate intake, but less in those on a higher fat intake. Multiple regression analysis of the relationships among carbohydrate intake (X1) and fat intake (X2) and changes in the linoleic acid percentage of total serum fatty acids (Y) in each case yielded an equation: Y =-4.75 X1 + 69.0 X2 - 27.9 (R = 0.885, p less than 0.05). Approximately 1 g/kg/day of fat provided in 40-50 kcal/kg/day of nonprotein energy intake was estimated to prevent decrease in the linoleic acid content in the serum fatty acid pattern during the postoperative catabolic stage.