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Energetic and metabolic cost of growth in Gambian infants
N Stettler1, Y Schutz, J L Micheli
1Institute of Physiology, Faculty of Medicine, University of Lausanne, Switzerland.
Insights
Energy expenditure for growth in breast-fed Gambian infants was measured. Sleeping energy expenditure correlated with weight gain, indicating lower growth efficiency compared to preterm infants.
Area of Science:
- Pediatrics
- Human Nutrition
- Infant Metabolism
Background:
- Assessing energy utilization for growth is crucial for understanding infant development.
- Breast-feeding is the primary nutrition source for many infants globally.
- Limited data exists on energy expenditure for growth in healthy, full-term, breast-fed infants in developing countries.
Purpose of the Study:
- To quantify the energy expenditure associated with growth in healthy, full-term, breast-fed Gambian infants.
- To determine the relationship between sleeping energy expenditure and weight gain.
- To estimate the energy cost of new tissue synthesis.
Main Methods:
- 14 healthy, full-term, breast-fed Gambian infants (mean age 17 days) were studied over 2 weeks.
- Energy intake (EI) was measured via breast milk analysis.
- Sleeping energy expenditure (SEE) and respiratory quotient (RQ) were measured five times over 24 hours.
Main Results:
- Average EI was 502 kJ/kg/day and SEE was 230 kJ/kg/day.
- Energy available for physical activity and growth was 272 kJ/kg/day.
- SEE showed a significant correlation with weight gain (r=0.747, P<0.005), with an estimated energy cost of 5.5 kJ/g for new tissue synthesis.
Conclusions:
- The energy cost of growth in these infants was estimated.
- The efficiency of weight gain (67%) was lower than reported for preterm infants or recovering malnourished children.
- Findings highlight potential differences in energy utilization for growth in diverse infant populations.
Abstract:
The aim of the study was to measure the energy used for growth of healthy fullterm and breast-fed Gambian infants. The weight gain (WG) of 14 infants (mean age +/- SEM 17 +/- 1 d, weight 3.581 +/- 0.105 kg) was measured over a 2-week period; the energy intake (EI) from breast milk was assessed for 24 h in the middle of the study period by weighing the infant before and after each breast-feed. On the same day, sleeping energy expenditure (SEE) and respiratory quotient (RQ) were measured for 30 min on five occasions through the 24-h period. EI averaged 502 +/- 25 kJ/kg.d, and SEE 230 +/- 6 kJ/kg.d; thus, an average of 272 kJ/kg.d were available for physical activity and the energy stored for growth. The total energy spent by infants while sleeping and for periods of physical activity was calculated to be 1.7 x SEE. The mean RQ measured on five occasions averaged 0.879 +/- 0.009. SEE was correlated with WG (r = 0.747, P less than 0.005), with a slope of the regression line of 5.5 kJ/g; this value can be considered as an estimate of the energy spent for new tissue synthesis in the resting infant. The efficiency of weight gain was lower in this study (67%) than in studies conducted on fast-growing preterm infants or children recovering from malnutrition.