Biologic substances present in human colostrums demonstrate the evolution of this essential nutrient for growth and development: Insulin-like growth factor-I and prolactin

The aim of the present study was to see whether the level of both insulin-like growth factor-I (IGF-I) and prolactin (PRL) present in the colostrums of women coming from fairly different environmental conditions showed any significant difference. To this end, the IGF-I and PRL levels of African and Italian women still living in their countries of origin were determined. The IGF-I levels of African women turned out to be lower than those of Italian women (11.53 ± 8.67 vs 29.16 ± 14.39 ng/mL) and, in addition, decreased significantly and progressively within the first 3 days after delivery. The IGF-I levels in the colostrums of Italian women who delivered by cesarean delivery were comparable to that of African women who delivered by spontaneous delivery. However, because the colostrum volume and the IGF-I level of African women are larger and lower, respectively, than those typical of Italian women, Italian and African newborns end up receiving roughly the same amount of IGF-I on day 1 after birth. Prolactin levels in Italian and African women were comparable (85.16 ± 29.14 and 74.88 ± 27.97 ng/mL) and were significantly reduced in 10 Italian women 2 days after the cesarean delivery (59.22 ± 12.96 ng/mL). The progressive decrease of IGF-I level detected in the first 3 days of life demonstrates the crucial role of IGF-I in the development of both gastrointestinal and immune systems. In addition, the stability of PRL levels in the first 3 days of life underlines the essential role of this hormone in the switching on of lactation as well as in the regulation of immune response.