Nutritional assessment using stable isotope ratios of carbon and nitrogen in the scalp hair of geriatric patients who received enteral and parenteral nutrition formulas.

BACKGROUND & AIMS: The δ13 C and δ15 N values in the scalp hair of geriatric patients in Japan who received the enteral or parenteral nutrition formula were measured to assess nutritional status.

METHODS: The relations among δ13 C, δ15 N, calorie intake, BMI, albumin concentration, total cholesterol (T-CHO) and geriatric nutritional risk index (GNRI) in the patients were investigated. Furthermore, the enrichment of δ13 C and δ15 N from the nutrients to the hair was investigated.

RESULTS: The δ13 C values in the hair of patients who received enteral nutrition decreased with decreases in the calories received, while the δ15 N values increased, suggesting malnutrition in some patients with a low calorie intake due to a negative nitrogen balance. The distribution of patients with a low calorie intake (below 20 kcal/kg/day) when δ13 C was plotted against δ15 N differed from that of control subjects, but the distribution of patients with a high calorie intake (above 20 kcal/kg/day) was similar to that of control subjects. No significant differences were observed in BMI, albumin concentration, T-CHO or GNRI between the low and high calorie groups. The enrichment of δ13 C and δ15 N from the enteral nutrients to the hair were inversely correlated with the δ13 C and δ15 N in the enteral nutrients. The enrichment levels of δ13 C and δ15 N tended to be higher and lower, respectively, in the high calorie group. On the other hand, the δ13 C and δ15 N values in the hair of patients who received parenteral nutrition were higher and lower than those in the control subjects and in the patients who received enteral nutrition, respectively, reflecting the higher δ13 C and lower δ15 N contents of the parenteral nutrients.

CONCLUSIONS: The δ13 C and δ15 N values in the hair of patients who received enteral nutrition may be effective indicators for evaluating the long-term nutritional status of geriatric patients. A calorie intake of 20 kcal/kg/day may be a cut-off value for malnutrition in Japanese geriatric patients receiving enteral nutrition. However, caution is necessary when dealing with patients switching from parental nutrition as parenteral nutrition resulted in different changes in δ13 C and δ15 N. The enrichment levels of δ13 C and δ15 N from the enteral nutrients to the hair may be inversely correlated with the δ13 C and δ15 N values of enteral nutrients and vary according to the calorie intake.