Temporal Changes in Insulin-Like Growth Factors I and II and in Insulin-Like Growth Factor Binding Proteins 1, 2, and 3 in Human Milk

Abstract

Aim: To evaluate the postpartum time course of changes in insulin-like growth factors (IGFs) and their binding proteins (IGFBPs). Methods: Breast milk IGF-I and IGF-II and IGFBP-1, IGFBP-2, and IGFBP-3 levels were determined in 23 women with babies born at term, from day 4 until up to 9 months after birth. Results: The IGFBP-3 levels were highest from day 4 to day 6 and then decreased by days 10–12. In contrast, IGF-I and IGF-II and IGFBP-1 and IGFBP-2 showed little change over the first 2 weeks after birth. Subsequently, all the IGF components showed a moderate decline over approximately the first 1–3 months and then stable levels up to 9 months after birth. Conclusion: Although the possibility cannot be excluded that these changes in levels of IGFs and their binding proteins in human milk represent passive loss from the mammary gland, we speculate that higher early levels of the human milk IGF system contribute to maturation of the infant gut.

The Study of Breast Milk IGF-1, Leptin, Ghrelin and Adiponectin Levels as Possible Reasons of High Weight Gain in Breast-Fed Infants

“…Our data are consistent with the data of other researchers [7,12,14,22,24,29], who also demonstrated the presence of IGF-1, leptin, ghrelin and adiponectin in breast milk and confirm their hypothesis that these breast milk proteins can play a role in the regulation of feeding behavior and energy homeostasis of breast-fed infants. Indeed, in our study, the infants in the high weight gain group, who were fed with breast milk with high hormone levels, consumed significantly more breast milk than the infants with low weight gain and had the highest growth rate.…”

“…Data on human milk IGF-1 levels were reported in many previous studies [12,13,14,15,16]. Milson et al [12] and Blum and Baumrucker [16] speculated that high early levels of the human milk IGF system contribute to the maturation of the infant gut. The majority of authors consider that breast milk IGF-1 can influence regulatory functions and growth of neonatal tissues in a direct or indirect way [12,14,16].…”

“…Milson et al [12] and Blum and Baumrucker [16] speculated that high early levels of the human milk IGF system contribute to the maturation of the infant gut. The majority of authors consider that breast milk IGF-1 can influence regulatory functions and growth of neonatal tissues in a direct or indirect way [12,14,16]. In our study, we also observed a positive correlation between the breast milk IGF-1 level and infant growth velocity.…”

Human Milk Composition

“…52-54 Levels are highest in colostrum, and steadily decline over the course of lactation. 55,56 There are no significant differences between preterm and term milk, with the exception of IGF binding protein-2, which is higher in preterm milk. 52,57 In rodents, administration of human IGF-I during surgical stress/total parental nutrition causes increased tissue growth, 58 and attenuates intestinal atrophy, 59 though no human trial has been conducted.…”

Insulin-Like Growth Factor 2/H19 Methylation at Birth and Risk of Overweight and Obesity in Children

“…It is possible that infants with H19 DMR hypermethylation at birth also are more likely to have metabolic dysregulation, which, together with infant formula, may increase the risk of obesity or overweight status. Also, breast milk contains not only IGF2 , but also IGF1 and IGF binding proteins (51). The early protein hypothesis posits that the higher levels of protein in infant formula exceed metabolic requirements, and that the metabolic products of excess protein may stimulate secretion of excess insulin and IGF1 , leading to increased weight gain in early life (52).…”