Relationship of Breast Milk Leptin with Maternal and Infant Adiposity

INTRODUCTION: Leptin the product of the obese gene (ob) is synthesized by adipose tissue and contributes to the regulation of energy homeostasis and food intake. Recently, immunoreactive leptin was reported to be present in human milk. The aim of this study was to determine any possible link between breast milk leptin concentrations and adiposity in exclusively breast-fed infants. METHODS: 130 healthy, exclusively breast-fed infants beyond neonatal period and their mothers were included in the study. Infants whose weight for age was above the 75th, and between 25th and 75th percentiles were defined as obese (n=65) and non-obese (n=65), respectively. Anthropometric measurements of infants and mothers were also made and breast milk samples were analyzed for leptin. RESULTS: There was no significant difference between breast milk leptin concentrations of mothers of obese and non-obese infants. Breast milk leptin concentrations significantly correlated with mothers' body mass index (r=0.54, P<0.001) and weight (r=0.46, P<0.001). There was no significant correlation between breast milk leptin concentration and weight of infants. CONCLUSIONS: Leptin concentrations of human milk are not different in the mothers of obese and non-obese infants. Our findings suggest that milk-borne leptin has no significant effect on adiposity during infancy.