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Energy metabolism in healthy black Kenyan children
1Department of Paediatrics, Sheffield University, Sheffield Children's Hospital.
Insights
In Kenyan children, a high-carbohydrate diet may increase energy cost for fat synthesis. Short-term fat storage appears normal in children
Area of Science:
- Pediatric Nutrition
- Human Metabolism
- Energy Balance
Background:
- Understanding energy expenditure and substrate utilization in children is crucial for growth and development.
- Dietary composition significantly influences metabolic processes and energy storage.
- Limited data exists on the metabolic responses of healthy African children to dietary intake.
Purpose of the Study:
- To investigate energy expenditure (EE) and substrate utilization in healthy Kenyan children.
- To assess the relationship between dietary intake, particularly carbohydrate, and metabolic rate.
- To evaluate body weight as a predictor of resting metabolic rate in this population.
Main Methods:
- Indirect calorimetry was used to measure oxygen consumption and carbon dioxide production over 24 hours.
- Metabolizable energy intake was quantified in a subset of participants.
- Anthropometric measurements were taken to estimate body composition and size.
Main Results:
- Postprandial energy expenditure was significantly higher than resting energy expenditure.
- A respiratory quotient (RQ) above 1.0 was observed in 33% of resting measurements, suggesting short-term fat synthesis.
- High carbohydrate intake was associated with an increased energy cost of fat synthesis.
Conclusions:
- Short-term fat storage is likely a normal metabolic process in children.
- High-carbohydrate diets may enhance the energy cost of fat synthesis in pediatric populations.
- Body weight is a reliable estimator of metabolic size in young children with varied body composition.
Abstract:
1. Twenty-four healthy black Kenyan children, mean age 29 (SD 19) months, were studied over a 24 h period. Energy expenditure (EE) was determined using a ventilated-hood indirect calorimeter; measuring oxygen consumption and carbon dioxide production. Metabolizable energy intake was measured in twenty children. Anthropometric measurements were used to estimate surface area and lean body-weight. 2. The mean daily intake of metabolizable energy was 338.4 (SE 28.4) kJ/kg; 70% of gross dietary energy being provided by carbohydrate. The level of postprandial EE was significantly (P less than 0.05) higher than the resting level (12.6 (SE 0.47) and 11.38 (SE 0.37) kJ/kg per h respectively) while the level of the postprandial respiratory quotient (RQ) was similar to the resting level (0.94 (SE 0.02) and 0.98 (SE 0.03 respectively). In 33% of total observations of the resting RQ the value was more than 1.0. These findings suggest that short-term fat storage may be a normal feature of metabolism in children, and also that the energy cost of (postprandial) fat synthesis is increased by a high-carbohydrate diet. 3. Values for the resting metabolic rate and various estimators of body size were compared using regression analysis. It was evident that, in these young children with considerable variation in body composition, body-weight remained a satisfactory metabolic-size estimator.