The study of breast milk IGF-1, leptin, ghrelin and adiponectin levels as possible reasons of high weight gain in breast-fed infants.

BACKGROUND

Excessive consumption of protein that leads to increased blood levels of insulin-like growth factor-1 (IGF-1) is an important risk factor for high growth velocity and obesity in formula-fed infants. However, it is not clear whether these factors can explain the high growth velocity in breast-fed infants.

AIM: To study the possible links between the growth velocity in breast-fed infants and the levels of protein, IGF-1 and other hormones, which regulate energy homeostasis, in mothers' breast milk.

METHODS

We studied 103 mother-infant pairs. Their daily breast milk intake and level of IGF-1, leptin, ghrelin, adiponectin, protein and fat in breast milk were measured at 1, 2 and 3 months of lactation. The infant group was divided into three subgroups of low, normal and high weight gain tertiles.

RESULTS

The breast milk consumed by the infants with high weight gain contained higher levels of IGF-1 than that consumed by those with low weight gain at all periods studied (p = 0.032 at 3 months of lactation), and ghrelin levels were higher at 1 and 2 months and leptin levels at 2 and 3 months of lactation (p < 0.05). A positive correlation was observed between the breast milk IGF-1 level and infant weight gain (r = 0.294, p = 0.043). Total daily breast milk, fat and hormone intake was also higher in the high weight gain group compared to the low weight gain group.

CONCLUSION

One of the reasons for the high growth velocity in breast-fed infants may be the enhanced levels of the studied hormones in breast milk.