Therapeutic Efficacy of an Elemental Diet for Patients with Crohn's Disease and its Association with Amino Acid Metabolism

BACKGROUND/AIM: We investigated the association between blood amino acid concentration changes caused by elemental diet (ED) and their relationship to its therapeutic effect. PATIENTS AND METHODS: Patients with active Crohn's disease (CD) followed ED for 12 weeks. Patients not previously treated with ED were defined as new ED, and those with previous ED therapy (≥900 kcal/day) were defined as previous ED. Disease activity markers [Crohn's disease activity index (CDAI) and C-reactive protein (CRP) level], blood biochemistry test results, and plasma amino acid concentrations were measured before and after the treatment. RESULTS: Histidine (His), tryptophan (Trp), valine (Val), and methionine (Met) increased after the treatment in the 17 patients with clinical remission, however, no increase occurred in plasma amino acid concentrations in the 8 patients without remission. The multivariate index using AminoIndex(™) technology (MIAI) was correlated with the CDAI (r = 0.475, P < 0.001), and it decreased as patients' conditions improved during the treatment. All patients in the new ED group (n = 11) exhibited increases in the nutritional indices, albumin level, and body mass index after treatment, as well as increased levels of His, Trp, Val, and phenylalanine. None of these changes were observed in the previous ED group (n = 14). CONCLUSIONS: Plasma amino acid concentrations and MIAI may provide useful noninvasive markers for evaluating disease activity and response to treatment. ED was effective in improving disease activity, nutritional status, and plasma amino acid levels, and thus it may be particularly effective for poorly nourished patients with CD who have not previously undergone this treatment.