Stable isotope ratios of carbon, nitrogen and selenium concentration in the scalp hair of Crohn's disease patients who ingested the elemental diet Elental®

Rationale Elental((R)) is an elemental diet widely used as a nutritional supplement for Crohn's disease (CD) patients in Japan. Elental((R)) contains amino acids as nitrogen sources and does not contain selenium (Se), and the delta C-13 and delta N-15 values of Elental((R)) are markedly higher and lower, respectively, than those of a normal diet. Methods We compared the delta C-13 and delta N-15 values and Se concentration in the scalp hair of CD patients with those of control subjects who ate a regular diet, and estimated the amount of Elental((R)) ingested as a supplement. The delta C-13 and delta N-15 values and the Se concentrations were quantified using isotope ratio mass spectrometry (IRMS) and inductively coupled plasma mass spectrometry (ICP-MS), respectively. Results An increase in Elental((R)) ingestion increased the delta C-13 value in the hair of CD patients (p <0.05), while it reduced the delta N-15 value (p <0.05) and tended to reduce the Se concentration in female patients. Conclusions The amount of Elental((R)) ingested could be estimated by the delta C-13 and delta N-15 values in the hair of CD patients. Furthermore, the Se deficiency in female patients may be predicted from the delta C-13 and delta N-15 values.