Structured versus long-chain triglycerides: A safety, tolerance, and efficacy randomized study in colorectal surgical patients

Background: After trauma or surgery, researchers have suggested that medium-chain triglycerides have metabolic advantages, although they are toxic in large doses. To try to reduce this potential toxicity, structured lipids, which provide a higher oxidation rate, faster clearance from blood, improved nitrogen balance, and less accumulation in the reticuloendothelial system, could be used. Therefore, we evaluated, through a blind randomized study, the safety, tolerance, and efficacy of structured triglycerides, compared with long-chain triglycerides (LCT), in patients undergoing colorectal surgery. Methods: Nineteen patients were randomized to receive long-chain or structured triglycerides as a lipid source. They received the same amount of calories (27.2/kg/d), glucose (4 g/kg/d), protein (0.2 g/kg/d), and lipids (11.2 kcal/kg/d). Patients were evaluated during and after the treatment for clinical and laboratory variables, daily and cumulative nitrogen balance, urinary excretion of 3-methylhistidine, and urinary 3-methylhistidine/creatinine ratio. Results: No adverse effect that required the interruption of the treatment was observed. Triglyceride levels and clinical and laboratory variables were similar in the two groups. A predominantly positive nitrogen balance was observed from day 2 until day 5 in the LCT group and from day 1 until day 4 in the structured triglycerides group. The cumulative nitrogen balance (in grams) for days 1 to 3 was 9.7 +/- 5.2 in the experimental group and 4.4 +/- 11.8 in the control group (p = .2). For days 1 to 5 it was 10.7 +/- 10.5 and 6.5 +/- 17.9 (p = .05), respectively. The excretion of S-methylhistidine was higher in the control group but decreased in the following days and was similar to the experimental group on day 5. Conclusions: This study represents the first report in which structured triglycerides are administered in postoperative patients to evaluate safety, tolerance, and efficacy. It suggests that Fe73403 is safe, well tolerated, and efficacious in terms of nitrogen balance when compared with LCT emulsion.