The impact of refeeding on blood fatty acids and amino acid profiles in elderly patients: A metabolomic analysis

Background: Refeeding of elderly frail patients after food deprivation is commonly associated with a high mortality rate. Objective: To evaluate the effect of refeeding on metabolite fluctuation of blood carnitine fatty acids (15 compounds) and free amino acids (14 compounds). Methods: Metabolite fluctuation was followed up in an exploratory, cohort, and noninterventional study in elderly and frail patients (84.5 ± 5 years) after a long period of food deprivation. Patients in the study group were refed by enteral nutrition (EN) and were followed up during 7 days for blood metabolites (n = 27). Patients in the control group (n = 26) had been fed by EN for more than 3 months. Refeeding was initiated with 10 kcal/kg/d and gradual increases of 200 kcal/d for 3 days afterwards. Blood metabolites were assayed in a sample of 25 μL. Results: On food deprivation, the concentrations of all even monocarboxylic carnitine fatty acids were much higher in the study group than in the EN control group (P <.01). Upon refeeding, a remarkable decrease in all carnitine fatty acids was observed. In addition, significant daily fluctuations were observed for most metabolites in the study group of the refed patients as compared with the EN control group (P <.01). The highest fluctuations were observed following refeeding in the 7 patients who later died. Conclusion: A significant metabolic instability is observed on refeeding even with a slow refeeding schedule of 10 kcal/kg/d. Measurement of metabolomics parameters may be used for the evaluation of malnutrition, refeeding status, and optimization of the enteral formula.