SOYBEAN OIL, BLACK-CURRANT SEED OIL, MEDIUM-CHAIN TRIGLYCERIDES, AND PLASMA PHOSPHOLIPID FATTY-ACIDS OF STRESSED PATIENTS

Thirty-six adult severe head injury and cerebral stroke patients in fo ur intensive-care units were randomized to receive one of three entera l diets for 21 days. These diets, which supplied 45% of calories from fat, differed only in lipid composition. Diet A was comprised of 100% soybean oil, diet B contained a 50:50 (wt/wt) mixture of soybean oil a nd medium-chain triglycerides (MCTs), and diet C contained 42.5% MCT, 50% soybean oil, and 7.5% blackcurrant seed oils. Plasma phosphatidylc holine and fatty acid composition of plasma total phospholipids were d etermined before initiating treatment (day 0) and weekly throughout th e study. Results indicated that at the start of the study, all patient s had low linoleic acid (18:2omega6) levels compared with healthy subj ects. Emulsion A disturbed the balance between several fatty acids of the omega6 series, as exemplified by the significant increase in 18:2o mega6 proportions. In contrast, both emulsions B and C introduced a le ss-pronounced rise in 18:2omega6 associated for emulsion C with a sign ificant increase in dihomo-gamma-linolenic acid (20:3omega6) and docos apentaenoic acid (22:5omega3) in plasma phospholipids. Furthermore, 18 :3omega6 change was significantly different between groups A and C and that of 20:3omega6 between group A and both groups B and C. Throughou t the study, arachidonic acid (20:4omega6) exhibited remarkable steady -state levels regardless of the diet. This study shows that providing the injured body with high amounts of 18:2omega6 does not lead to high levels of its upper derivatives in plasma phospholipids. Dividing the soybean oil supply by 50% through an addition of MCT and supplementat ion with gamma-linolenic (18:3omega6) and stearidonic (18:4omega3) aci ds modifies the balance of some eicosanoid precursors in a way that ma y be more suited to stressed patients.