Validation of a field method for measuring breastmtlk intake using deuterium oxide and infrared spectroscopy

Deuterium dilution is a well-established method for measuring breast milk intake However, analysis by isotope ratio mass spectrometry (IRMS) is expensive. The present study evaluated the feasibility of using a protocol adapted to field conditions and measuring deuterium oxide by infrared (IR) spectroscopy. Rural Indonesian lactating mothers received a 30 g oral dose of D₂O. Four maternal milk samples and 9 infant urine samples were collected during the 14 days following the D₂O dose Isotopic enrichment was determined for 12 subject pairs by both IR spectroscopy and IRMS, and compartmental modeling was used to predict infant milk intake. The compartmental model produced good fits to the enrichment data for all subjects. The mean predicted milk intakes were 575 mL for IR and 581 mL for IRMS. A paired t test was performed to compare predicted milk intakes from the IR and IRMS analyses, and the predicted milk intakes for the two methods were not significantly different (p<0.001). In conclusion, deuterium dilution in combination with IR spectroscopy offers a feasible and inexpensive method for determining milk intake in field laboratories.