Concentration of ghrelin and leptin in serum and human milk in nursing mothers according to the type of feeding.

Objective: we assessed the relationship between serum and human foremilk and hindmilk concentrations of ghrelin and leptin in nursing mothers according to the type of feeding. Methods: this cohort design was carried out on 131 mother-newborn dyads admitted to a physiological puerperium ward. The independent variables were the type of feeding, full breastfeeding (FBF, 56.5%) and partial breastfeeding (PBF, 43.5%). The dependent variables were the concentration of total ghrelin (pg/ml) and leptin (ng/ml) in serum, foremilk and hindmilk at eight and 16 weeks. Fasting blood samples were obtained from the nursing mothers at four months for serum assays. Unpaired Student's t-test, Mann-Whitney U test, Pearson's correlation tests, coefficient of determination and linear regression were used. Results: the concentration of ghrelin and leptin in hindmilk was higher than that of foremilk in both groups at eight and 16 weeks. The concentration of ghrelin and leptin was higher in serum than in foremilk in both groups. These values showed a direct and significant linear correlation with the exception of ghrelin in the FBF group. The serum concentration of leptin in mothers explained 32% of the variance of its concentration in foremilk in the FBF and 13% in the PBF groups. Conclusion: the hindmilk/foremilk gradient suggests an intake regulating mechanism during the fed. The concentration of ghrelin and leptin was higher in the serum than in foremilk and its correlation and determination coefficients could suggest plasma-milk transfer in addition to synthesis regulation by the mammary gland, adipose tissue or other organs.