Plasma beta-endorphin and insulin concentrations in relation to body fat and nutritional parameters in overweight and obese prepubertal children

OBJECTIVE: To investigate the relationship between plasma beta-endorphin (beta-end) and insulin concentrations and 1) body fat, and 2) nutritional parameters in overweight or obese prepubertal children. DESIGN: Cross-sectional study on plasma beta-end and insulin concentrations, body fat, indirect parameters of appetite namely daily energy and macronutrient intake. SUBJECTS: 143 (67 boys and 76 girls) overweight or obese children (group I) and 48 (27 boys and 21 girls) healthy children with normal parameters of somatic development (group II). Age: 5.8-9.6 y. MEASUREMENTS: Weight, height and subcutaneous skinfold thicknesses, plasma beta-end and insulin concentrations, diet history for energy and macronutrient intake. RESULTS: Group I was characterised by significantly higher average concentrations of beta-end and insulin in comparison to the control group. The analysis of these concentrations in the subgroups in relation to the percentage of body fat indicates that beta-end concentrations increased more than insulin concentrations with increasing fatness. A significantly positive correlation between beta-end and insulin levels was only noted in group 1. Also, only in this group was there a significant positive correlation between beta-end levels and energy and macronutrient intake. In both groups the percentage of energy intake which was fat, correlated positively with beta-end concentrations. Furthermore energy and fat intakes showed a significant positive correlation with insulin levels in both groups. CONCLUSIONS: beta-endorphin and insulin concentrations in overweight and obese prepubertal children are not only higher than in non-obese children but also are positively correlated with each other and with the percentage of body fat. The relationship between plasma beta-end levels and food intake shows that the beta-end lever may be able to be used as an indicator of appetite in overweight and obese prepubertal children whose food intake is not restricted.