Effect of Breastfeeding on Serum Osteoprotegerin and Soluble Receptor Activator of Nuclear Factor-Kappa B Ligand in Full Term Neonates

BACKGROUND Human breast milk, the sole source of nutrition during the early neonatal period, is rich in nutrients, hormones, growth factors, and immunoactive molecules, which influence the growth, development, and immune status of the newborn infant. It had long been thought that breast milk is an adequate source of anthracitic activity for the newborns and growing child. OBJECTIVE Human milk is a complex biologic fluid which contains nutritional and protective factors such as Osteoprotegerin (OPG), at levels 1000-fold higher than normal human serum. Since OPG and Receptor activator of nuclear factor-kappa B ligand (RANKL) system are tightly involved in bone remodeling and immune activity, the study was designated to evaluate the effect of breastfeeding on serum soluble receptor activator of nuclear factor-kappa B ligand (sRANKL) /OPG ratio in full term neonates in comparison with those of formula feeding full term neonates. MATERIALS AND METHODS In this cross-sectional study serum levels of OPG and sRANKL in 45 breastfed infants were compared to those of 44 formula-fed full term infants. The levels of serum OPG, sRANKL, and Tumor necrosis factor alpha (TNFα) were determined by standard techniques using enzyme-linked immunosorbent assay kits. RESULTS The serum levels of OPG were significantly higher (P < 0.001), and the concentrations of TNFα was markedly lower (P = 0.024) in breastfed infants than those of formula-fed infants. No marked differences were observed between the serum levels of sRANKL in the two study groups (P = 0.8). CONCLUSIONS High OPG and low TNFα levels in serum of breastfed infants are important factors involved in remodeling of bone, and immune activity may prove superiority of breastfeeding over formula feeding during infancy.