Nf. Butte et al., HIGHER TOTAL-ENERGY EXPENDITURE CONTRIBUTES TO GROWTH FALTERING IN BREAST-FED INFANTS LIVING IN RURAL MEXICO, The Journal of nutrition, 123(6), 1993, pp. 1028-1035
To investigate the energy requirements of infants living under unfavor
able environmental conditions in rural Mexico, we measured the total e
nergy expenditure (TEE) of 40 Otomi infants at approximately 4 or appr
oximately 6 mo of age. Total energy expenditure was estimated by the d
oubly labeled water method: 100 mg (H2O)-H-2/kg and 250 mg O-18/kg wer
e administered orally, after which urine was collected serially for 7
or 10 d. Isotopic enrichment of urine samples was analyzed by gas-isot
ope-ratio mass spectrometry. Weight and length were measured monthly f
rom birth to 6 mo. Fat free mass was estimated from O-18 dilution spac
es. Total energy expenditures (mean +/- SD) were 310 +/- 58 and 318 +/
- 29 kJ.kg-1.d-1 at approximately 4 and approximately 6 mo, respective
ly. Total energy expenditure was higher than that previously observed
for breast-fed infants reared under more protected environments (268 /- 29 kJ.kg-1.d-1). Weight, length and weight gain were 5.9 +/- 0.8 kg
, 60 +/- 2 cm and 2.9 +/- 2.4 g.kg-1d-1 at 4.25 mo and 7.1 +/- 0.8 kg,
65 +/- 2 cm and 1.0 +/- 1.2 g.kg-1.d-1 at 6.27 mo. Growth faltering w
as evident at 6 mo by clinically significant declines in growth veloci
ties and National Center for Health Statistics Z-scores. Body fat of t
he Otomi infants averaged 21 +/- 6 and 18 +/- 5 g/100 g at approximate
ly 4 and approximately 6 mo, respectively. Higher rates of TEE narrowe
d the margin of energy available for growth and thereby contributed to
growth faltering in the Otomi infants.