Ghrelin--an indicator for fat oxidation in obese children and adolescents during a weight reduction program.
The aim of this study was to investigate the effect of short-term energy restriction combined with physical activity on changes in substrate oxidation and changes in plasma concentrations of ghrelin. We designed a longitudinal intervention study of 4.2 MJ (= 1,000 kcal) daily with exercise. Eighteen obese children and adolescents (age: 13.1 +/- 1.6 years, 13 girls, 5 boys, 17 White, 1 Black) participated. We measured body mass index (BMI), plasma ghrelin, resting energy expenditure (REE), VCO2, VO2 and respiratory quotient (RQ) at baseline and after 10 days. There was a significant decrease of BMI during the 10 day program (28.6 +/- 4.3 vs 27.5 +/- 4.2; p < 0.001). Ghrelin and RQ showed a tendency to increase, but the difference did not reach significance (ghrelin: 83.4 +/- 37.1 vs 99.5 +/- 41.2, p = 0067; RQ: 0.83 +/- 0.06 vs 0.85 +/- 0.08, p = 0.433). The changes in RQ were significantly and independently correlated with the changes in plasma ghrelin (p = 0.029). The increase in RQ suggests a shift from fat oxidation towards carbohydrate oxidation. Ghrelin reflects the same sensitivity as RQ to changes in energy balance. Therefore, ghrelin seems to be a sensitive indicator for changes in substrate oxidation.
Department of Pediatrics, University of Graz, Austria. hildegard.nitsche@meduni-graz.at
Hildegard
H
Nitsche
Marianne
M
Nitsche
Karl
K
Sudi
Matthias
M
Tschop
Heinz
H
Zotter
Gudrun
G
Weinhand
Elke
E
Froehlich-Reiterer
Siegfried
S
Gallistl
Martina
M
Pirker
Martin
M
Borkenstein
D000293:Adolescent; D015415:Biomarkers / Q000097:blood*; D015992:Body Mass Index; D002648:Child; D004041:Dietary Fats / Q000493:pharmacokinetics*; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D054439:Ghrelin; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009043:Motor Activity; D009765:Obesity / Q000097:blood* / Q000178:diet therapy* / Q000453:epidemiology; D010101:Oxygen Consumption / Q000502:physiology; D036361:Peptide Hormones / Q000097:blood*; D010809:Physical Fitness; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D015431:Weight Loss / Q000502:physiology*
D015415:Biomarkers; D004041:Dietary Fats; D054439:Ghrelin; D036361:Peptide Hormones