Effects of long-term continuous use of immune-enhancing enteral formula on nutritional and immunologic status in non-surgical patients

Objective: Although the perioperative use of immune-enhancing enteral formula (IEEF) effectively reduces the rate of infectious complications, whether chronic use of IEEF is beneficial is unknown. A prospective randomized clinical trial was performed to examine the safety and effectiveness of long-term IEEF on nutritional and immunologic status in non-surgical patients receiving total enteral nutrition through the gastrostomy access route. Methods: A total of 30 patients were randomly assigned to two groups in which they received total enteral nutrition, an IEEF (n = 15) or a regular polymeric enteral formula (control group; n = 15) for 12 wk. Nutritional and immunologic variables were periodically examined. Results: Serum concentrations of insulin-like growth factor-I increased significantly for the IEEF group throughout the study. Although serum concentrations of dihomo-γ-linoleic acid decreased significantly in the IEEF group, serum concentrations of eicosapentaenoic acid and docosahexaenoic acid increased significantly, as did concentrations of serum arginine and ornithine. The CD4/CD8 ratio and natural killer cell activity also increased for the IEEF group, but the differences were not significant. The B-cell fraction increased and the T-cell fraction of peripheral lymphocytes decreased for the IEEF group. Neither infectious nor non-infectious complications occurred during the study period in either group, except for a significant increase in serum urea nitrogen and uric acid concentrations for the IEEF group. Conclusion: Long-term use of IEEF is safe in non-surgical patients and results in a significant increase in serum insulin-like growth factor-I concentrations in association with increased humoral immunity.