CORRECTION FOR ENVIRONMENTAL WATER INFLUX IN MEASUREMENT OF MILK VOLUME INTAKE BY DEUTERIUM TURNOVER IN INFANTS

Measurement of milk volume intake (MVI) in infants is a useful tool fo r assessing nutritional intake. Current measurement techniques include test-weighing, weighing formula-bottles, and calculation of MVI from water turnover estimated isotopically. Test-weighing of breast-fed inf ants may disturb normal feeding behaviour and thus influence intake. C alculation of MVI from water turnover is a non-invasive measurement me thod and can be applied to all infants whether breast-fed or formula-f ed. The method requires correction for environmental water influx (EWI ) which constitutes non-oral water intake. EWI has previously been inv estigated only in premature or malnourished infants. The correction fa ctor for EWI was calculated by comparing MVI obtained from weighing fo rmula-bottles and measured isotopically in 21 formula-fed infants at 1 2 weeks of age. The mean correction factor, by which total water intak e should be adjusted to obtain oral water intake, was 0.937 (S.E. 0.01 7). The proportion of water intake derived from non-oral sources was t herefore 6.3%.