Believe it or not, many aspects and functions of the milk that we take from our mothers’ breast at birth are still unknown. A Spanish study published in the American Journal of Clinical Nutrition has thoroughly examined the bacterial flora of breast milk and has discovered that there is a great microbial diversity, with more than 700 different organisms.
Breast milk plays a fundamental role in the baby’s bacterial flora and therefore in the future protection of the child and its digestive system. However, the exact composition of it and the amount of bacteria that compose it was not known. To analyze it, the authors of the research, belonging to the Institute of Agrochemistry and Food Technology (IATA-CSIC) and the Higher Center for Research in Public Health (CSISP-GVA), used a massive DNA sequencing technique, pyrosequencing . Thanks to it, they have discovered that in breast milk there are more than 700 different types of bacteria, many more than previously believed.
The bacterial genera most present in the colostrum secreted by the mother after childbirth are the bacteria Leuconostoc, Staphylococcus, Streptococcus and Lactococcus . However, between the first and the sixth month after delivery, the appearance of bacteria typical of the oral cavity, such as Veillonella, Leptotrichia and Prevotella, was observed. However this appearance is still a mystery. As the researchers point out to the SINC Scientific News and Information Service, “it has not yet been possible to determine whether these bacteria colonize the baby’s mouth or whether the bacteria from the infant’s mouth enter breast milk by changing its composition.
How does the weight of the mother or the type of delivery affect?
In addition, the study has analyzed how the weight of the mother or the type of delivery affects the amount and diversity of bacteria. According to research, women who gain more weight than recommended during pregnancy have less biodiversity in the milk they produce . Similarly, mothers who give birth with a scheduled cesarean section give milk that is poorer in microorganisms than if the delivery was vaginal.
In the words of the principal researchers María Carmen Collado and Alex Mira to the SINC agency, ” The lack of physiological stress signals, as well as the hormonal signals typical of labor, could influence the composition and microbial diversity of breast milk “.
The knowledge of the bacterial composition of milk will serve for future studies on the development of the baby’s immune system , helping to reduce the risk of allergies and certain autoimmune diseases. For now, the researchers will try to determine in the coming months the role of bacteria in the baby to know if it has a metabolic function (to improve the digestion of milk by the newborn) or an immune function (to distinguish pathogenic organisms).
