Why are nutritionally stunted children at increased risk of obesity? Studies of metabolic rate and fat oxidation in shantytown children from São Paulo, Brazil.
BACKGROUND
Previous research suggested that nutritionally stunted children may have increased risk of obesity, but little is known about potential underlying mechanisms.


OBJECTIVE
We sought to test the hypothesis that stunted children have a low metabolic rate and impaired fat oxidation relative to nonstunted children.


METHODS
The subjects were 58 prepubertal boys and girls aged 8-11 y from the shantytowns of São Paulo, Brazil. Twenty-eight were stunted (height-for-age z score <-1.5) and 30 had similar weight-for-height but normal height (height-for-age z score >-1.5). Parents of children in the 2 groups had equivalent height and body mass index values. Fasting and postprandial energy expenditure, respiratory quotient (RQ), and substrate oxidation were measured with indirect calorimetry in a 3-d resident study in which all food was provided and body composition was measured with dual-energy X-ray absorptiometry.


RESULTS
Stunted children had normal resting energy expenditure relative to body composition compared with control children (4559 +/- 90 and 4755 +/- 86 kJ/d, respectively; P: = 0.14) and had normal postprandial thermogenesis (2.4 +/- 0.3% and 2.0 +/- 0.3% of meal load, respectively; P: = 0.42). However, fasting RQ was significantly higher in the stunted group (0.92 +/- 0.009 compared with 0.89 +/- 0.007; P: = 0.04) and consequently, fasting fat oxidation was significantly lower (25 +/- 2% compared with 34 +/- 2% of energy expenditure; P: < 0.01).


CONCLUSIONS
Childhood nutritional stunting is associated with impaired fat oxidation, a factor that predicted obesity in other at-risk populations. This finding may help explain recent increases in body fatness and the prevalence of obesity among stunted adults and adolescents in developing countries.
Hoffman
D J
DJ
Federal University of São Paulo, Escola Paulista de Medicina, São Paulo, Brazil.
Sawaya
A L
AL
Verreschi
I
I
Tucker
K L
KL
Roberts
S B
SB
D001823:Body Composition; D001827:Body Height; D001938:Brazil; D002648:Child; D002658:Developmental Disabilities / Q000209:etiology* / Q000378:metabolism / Q000473:pathology*; D004041:Dietary Fats / Q000378:metabolism; D004734:Energy Metabolism; D005215:Fasting / Q000502:physiology; D006801:Humans; D009748:Nutrition Disorders / Q000150:complications* / Q000378:metabolism / Q000473:pathology*; D009765:Obesity / Q000209:etiology*; D010084:Oxidation-Reduction; D011204:Poverty Areas; D012119:Respiration; D012307:Risk Factors
D004041:Dietary Fats