Endocrine and Metabolic Biomarkers Predicting Early Childhood Obesity Risk.

There is growing evidence of long-term effects of early dietary intervention in infancy on later obesity risk. Many studies showed reduced risk of obesity with breastfeeding in infancy, which could be related to the reduced protein intake with human milk compared to infant formula. In a randomized controlled trial (Childhood Obesity Project), we were able to show that infant formula with reduced protein content results in lower BMI both at 2 and 6 years. These effects seem to be mediated mainly by branched-chain amino acids which stimulate the insulin-like growth factor (IGF)-1 axis and insulin release. In this trial, we also showed an influence of high-protein diet on larger kidney size, which seems to be partly explained by a significant effect of free IGF-1 on kidney volume. The IGF-1 axis was shown to regulate early growth, adipose tissue differentiation and early adipogenesis in animals and in humans. Leptin and adiponectin can also be regarded as important endocrine regulators of obesity. These markers were tested in observational studies. Leptin seems to be closely correlated with BMI but changes in adiponectin require further exploration. Still, there is a lack of good data or some results are contradictory to indicate the role of either leptin or adiponectin in infancy for determining later obesity risk.